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LTE Radio Access, Rel. RL40,

Operating Documention

Recommended Configurations forSingleRAN Transport Sharing

DN09123915Issue 03

Approval Date 2013-01-23

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Recommended Configuration for SingleRAN TransportSharing

Table of contentsThis document has 72 pages.

Summary of changes ...................................................................................................... 6List of figures ................................................................................................................... 7List of tables .................................................................................................................... 81 Introduction ....................................................................................................... 91.1 Purpose ............................................................................................................ 91.2 Overview on the network reference configuration ............................................ 91.3 Release information ......................................................................................... 91.4 Feature interdependencies overview ............................................................... 91.4.1 GSM ................................................................................................................. 91.4.2 WCDMA ......................................................................................................... 101.4.3 LTE ................................................................................................................. 111.5 Input traffic models ......................................................................................... 121.5.1 GSM ............................................................................................................... 12

1.5.2 WCDMA ......................................................................................................... 121.5.3 LTE ................................................................................................................. 152 Common aspects ........................................................................................... 162.1 Hardware ........................................................................................................ 162.1.1 Base Transceiver Station ............................................................................... 162.1.2 Radio controllers ............................................................................................ 162.1.3 Miscellaneous ................................................................................................. 162.2 IP-based BTS connection .............................................................................. 172.2.1 GSM Packet Abis ........................................................................................... 172.2.2 WCDMA IP-based Iub .................................................................................... 172.2.3 LTE IP-based S1/X2....................................................................................... 172.3 Mobile Backhaul Network ............................................................................... 172.4 Quality of Service ........................................................................................... 20

2.4.1 Traffic Marking with DSCP ............................................................................. 212.4.1.1 DSCP marking for GSM ................................................................................. 222.4.1.2 DSCP marking for WCDMA ........................................................................... 222.4.1.3 DSCP marking for LTE ................................................................................... 232.4.2 Traffic Marking with PCP ................................................................................ 242.4.3 Ingress Rate Limiting in BTS internal switch .................................................. 242.4.4 Uplink Shaping and Scheduling ..................................................................... 252.4.5 Controlling Downlink Traffic ........................................................................... 262.5 Congestion Control Mechanisms ................................................................... 262.5.1 Packet Abis Congestion Control .................................................................... 262.5.2 WCDMA internal flow control ......................................................................... 282.5.3 HSDPA congestion control ............................................................................. 282.5.4 HSUPA congestion control ............................................................................. 29

2.5.5 TCP congestion control for LTE ..................................................................... 302.6 RF sharing ...................................................................................................... 302.7 Physical connectivity at BTS site ................................................................... 302.8 Synchronization on BTS site .......................................................................... 302.9 IP addressing ................................................................................................. 312.9.1 VLAN usage at BTS site ................................................................................ 312.9.2 Routing configuration in MBH ........................................................................ 312.9.2.1 Routing configuration with BFD-triggered static routes .................................. 312.9.2.2 Routing configuration with HSRP/VRRP ........................................................ 342.9.3 IP address for SSE ......................................................................................... 36




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2.9.4 Controller site ................................................................................................. 362.10 Traffic Aggregation on BTS site ..................................................................... 372.11 Security .......................................................................................................... 382.12 Auto-configuration .......................................................................................... 38

2.12.1 Measurements ................................................................................................ 382.12.1.1 GSM measurements ...................................................................................... 382.12.1.2 WCDMA measurements................................................................................. 392.12.1.3 LTE measurements ........................................................................................ 393 GSM and WCDMA ......................................................................................... 413.1 Recommended network configuration description ......................................... 413.1.1 General configuration ..................................................................................... 413.1.2 Feature usage ................................................................................................ 433.1.2.1 GSM ............................................................................................................... 433.1.2.2 WCDMA ......................................................................................................... 433.2 RAN parameters for the configuration ............................................................ 443.2.1 General ........................................................................................................... 443.2.2 Shaping .......................................................................................................... 44

3.2.3 Synchronization .............................................................................................. 473.2.4 BTS site 1 (standalone site) ........................................................................... 483.2.5 BTS site 2 (hub site) ....................................................................................... 483.2.6 BTS site 3 (leaf site) ....................................................................................... 493.2.7 BTS IP configuration ...................................................................................... 493.2.8 Controller site ................................................................................................. 494 GSM and LTE ................................................................................................. 504.1 Recommended Network Configuration Description ....................................... 504.1.1 General configuration ..................................................................................... 504.1.2 Feature usage ................................................................................................ 514.1.2.1 GSM ............................................................................................................... 514.1.2.2 LTE ................................................................................................................. 524.2 RAN parameters for the configuration ............................................................ 52

4.2.1 General ........................................................................................................... 524.2.2 Shaping .......................................................................................................... 524.2.3 VLAN Filtering ................................................................................................ 544.2.4 Synchronization .............................................................................................. 554.2.5 BTS site 1 (standalone site) ........................................................................... 554.2.6 BTS site 2 (hub site) ....................................................................................... 564.2.7 BTS site 3 (leaf site) ....................................................................................... 574.2.8 BTS IP configuration ...................................................................................... 574.2.9 Controller site ................................................................................................. 585 WCDMA and LTE ........................................................................................... 595.1 Recommended Network Configuration Description ....................................... 595.1.1 General configuration ..................................................................................... 595.1.2 Feature usage ................................................................................................ 61

5.1.2.1 WCDMA ......................................................................................................... 615.1.2.2 LTE ................................................................................................................. 615.2 RAN parameters for the configuration ............................................................ 625.2.1 General ........................................................................................................... 625.2.2 Shaping .......................................................................................................... 625.2.3 VLAN Filtering ................................................................................................ 635.2.4 Synchronization .............................................................................................. 645.2.5 BTS site 1 (standalone site) ........................................................................... 655.2.6 BTS site 2 (hub site) ....................................................................................... 665.2.7 BTS site 3 (leaf site) ....................................................................................... 68




5.2.8 BTS IP configuration ...................................................................................... 685.2.9 Controller site ................................................................................................. 686 Other notes ..................................................................................................... 72




DN09123915Issue 03

Summary of changes

Changes between document issues are cumulative. Therefore, the latestdocument issue contains all changes made to previous issues.

Changes between issues 02 (2013-01-10, WCDMA RAN, RU40) and 03(2013-01-23, LTE Radio Access, RL40)

• Editorial revisions.

Changes between issues 01C (2013-01-10, WCDMA RAN, RU30) and 02(2013-01-10, WCDMA RAN, RU40)


Changes between issues 01B (2013-01-10, LTE Radio Access RL30) and01C (2013-01-10, WCDMA RAN, RU30)


Changes between issues 01A (2012-11-23, WCDMA RAN RU30) and 01B(2013-01-15, LTE Radio Access, RL30)

• Table 40: VLAN filtering in WCDMA+LTE configuration has beenupdated

• Chapter 5.2.3: VLAN filtering has been updated. • Editorial revisions.

Changes between issues 01 (2012-08-14, WCDMA RAN RU30) and 01A(2012-11-23, WCDMA RAN RU30)

• I-HSPA rebranding.• Editorial revisions.




List of figuresFigure 1: Logical model of Ethernet service ................................................................ 18 Figure 2: Common MBH topology ............................................................................... 20 Figure 3: Shaping functionalities in BTS ..................................................................... 25 Figure 4: Routing configuration for BFD-triggered static routes.................................. 32 Figure 5: Routing configuration for HSRP ................................................................... 34 Figure 6: Accedian Metronode as measurement device for LTE ................................ 40 Figure 7: Several Ethernet services with single performance class ........................... 42 Figure 8: Shaping for GSM and WCDMA ................................................................... 46 Figure 9: Synchronization overview for GSM and WCDMA co-location ..................... 47 Figure 10: GSM + WCDMA BTS site 1 (standalone site) ........................................... 48 Figure 11: GSM + WCDMA BTS site 2 (hub site) ....................................................... 49 Figure 12: Two Ethernet services with single performance class ............................... 51 Figure 13: Shaping for GSM + LTE configuration ....................................................... 54 Figure 14: VLAN IDs used in GSM+LTE configuration ............................................... 54 Figure 15: GSM and LTE synchronization .................................................................. 55 Figure 16: GSM + LTE BTS site 1 (standalone site)configuration .............................. 56 Figure 17: GSM+LTE BTS site 2 (hub site) ................................................................ 56 Figure 18: GSM+LTE BTS site 3 (leaf site) ................................................................. 57 Figure 19: Several Ethernet services with single performance class ......................... 60 Figure 20: Shaping for WCDMA + LTE configuration ................................................. 63 Figure 21: VLAN IDs used in WCDMA+LTE configuration ......................................... 64 Figure 22: Synchronization overview for WCDMA and LTE co-location ..................... 65 Figure 23: WCDMA + LTE BTS site 1 (standalone site) ............................................. 65 Figure 24: WCDMA + LTE BTS site 2 (hub site) ......................................................... 66 Figure 25: WCDMA + LTE BTS site 3 (leaf site) ......................................................... 68




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List of tablesTable 1: Average traffic per GSM BTS ........................................................................ 12 Table 2: Average user traffic per WCDMA BTS .......................................................... 13 Table 3: Traffic demand on Iub per single BTS .......................................................... 14 Table 4: LTE traffic model ........................................................................................... 15 Table 5: BTS transport interfaces ............................................................................... 16 Table 6: GSM multiplexing .......................................................................................... 17 Table 7: Attributes of performance classes ................................................................. 19 Table 8: RAT service classes to TA/FC/DSCP mapping ............................................ 22 Table 9: DSCP marking for GSM ................................................................................ 22 Table 10: DSCP marking for WCDMA user plane ...................................................... 23 Table 11: DSCP marking for WCDMA non-user plane traffic ..................................... 23 Table 12: DSCP marking for LTE ................................................................................ 24 Table 13: PCP marking ............................................................................................... 24 Table 14: 1SP+5WFQ scheduler ................................................................................ 25 Table 15: Packet Abis Congestion Control Parameters .............................................. 27 Table 16: Queue weights in RNC ................................................................................ 28 Table 17: WCDMA SPI definitions .............................................................................. 29 Table 18: HSUPA congestion control threshold parameters ...................................... 29 Table 19: Synchronization roles for RF sharing .......................................................... 30 Table 20: Static route configuration for downlink traffic .............................................. 33 Table 21: WCDMA BTS uplink route configuration ..................................................... 33 Table 22: WCDMA BTS BFD session parameters ..................................................... 34 Table 23: VLAN and IP address overview .................................................................. 35 Table 24: HSRP configuration ..................................................................................... 36 Table 25: VLAN IDs ..................................................................................................... 38 Table 26: WCDMA IP measurements ......................................................................... 39 Table 27: LTE IP measurements ................................................................................ 40 Table 28: GSM and WCDMA traffic amount ............................................................... 43 Table 29: GSM / WCDMA information rates ............................................................... 43 Table 30: IP based route configuration ....................................................................... 45 Table 31: GSM BTS uplink shaping parameters ......................................................... 45 Table 32: WCDMA BTS uplink shaping parameters ................................................... 46 Table 33: GSM BTS as IEEE1588 slave ..................................................................... 47 Table 34: WCDMA BTS as SyncE slave ..................................................................... 48 Table 35: LTE BTS uplink shaping parameters .......................................................... 53 Table 36: VLAN filtering in GSM+LTE configuration ................................................... 55 Table 37: LTE and W CDMA traffic amount ................................................................. 60 Table 38: WCDMA+LTE information rates .................................................................. 61 Table 39: Uplink shaping for WCDMA and LTE configuration .................................... 63 Table 40: VLAN filtering in WCDMA+LTE configuration ............................................. 64 Table 41: WCDMA BTS as IEEE1588 slave and Master on E1 ................................. 66 Table 42: WCDMA BTS as IEEE1588 slave and SyncE master ................................ 67




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BSS21502 Cisco 76xx as Flexi BSC site router

BSS30395 Packet Abis Delay Measurement

BSS30450 Packet Abis Synchronous Ethernet

Other features used in the reference configurations:

BSS09006 GPRS System Feature Description

BSS10091 EDGE System Feature Description

BSS21520 RF Sharing GSM-LTE

1.4.2 WCDMAThe WCDMA transport related features are:

RAN74 IP-based Iub

RAN1016 Flexi BTS Multimode System Module

RAN1155 Flexi WCDMA BTS Eth+E1/T1/JT1 Sub-Module 'FTIB' with Timingover Packet

RAN1159 IP Address & Port based Filtering for BTS LMPs

RAN1254 Timing over Packet for BTS Application SW

RAN1708 BTS Synchronous Ethernet

RAN1709 VLAN traffic differentiation

RAN1749 BTS Firewall

RAN1769 QoS aware Ethernet switching

RAN1819 Transport sub-module FTLB for Flexi Multimode BTS

RAN1848 Flexi BTS Multimode System Module - FSME

RAN1884 Cisco 76xx as RNC Site Router

RAN1886 Efficient Transport for small IP packets

RAN1900 IP Transport Network Measurement

RAN2071 Synchronous Ethernet Generation 1

RAN2382 Flexi BTS Multimode System Module - FSMC

RAN2440 Fast IP Rerouting

Other features used in the reference configurations:

RAN992 HSUPA Congestion Control

RAN1004 Streaming QoS for HSPA (streaming over HSPA)

RAN1110 HSDPA Congestion Control

RAN1201 Fractional DPCH (SRB over HSPA)

1 RAN2071 Synchronous Ethernet Generation uses the same license key asRAN1708 BTS Synchronous Ethernet




RAN1262 QoS aware HSPA scheduling (streaming over HSPA)

RAN1298 BTS Auto Connection

RAN1299 BTS Auto Configuration

RAN1470 HSUPA 2ms TTI (SRB over HSPA)

RAN1638 Flexible RLC (DL)

RAN1643 HSDPA 64QAM (21.1Mbps peak rate)

RAN1645 HSUPA 16QAM (11.5Mbps peak rate)

RAN1906 Dual-Cell HSDPA 42Mbps (together with RAN1643)

RAN1910 Flexible RLC in uplink

RAN1912 MIMO 42 Mbps

RAN2067 LTE Interworking

RAN2123 Flexi BTS Gigabit Baseband

1.4.3 LTEThe LTE transport related feature s are as follows:

LTE74 Flexi System Module FSMD

LTE82 High Capacity Flexi System Module FSME

LTE118 Fast Ethernet (FE) / Gigabit Ethernet (GE) electrical interface

LTE119 Gigabit Ethernet (GE) optical interface

LTE129 Traffic prioritization on Ethernet layer

LTE131 Traffic prioritization on IP layer (Diffserv)

LTE132 VLAN based traffic differentiation

LTE134 Timing over Packet

LTE138 Traffic shaping (UL)

LTE144 Transport admission control

LTE504 Cisco76xx as Edge Router and Security Gateway

LTE574 IP Transport Network Measurement

LTE592 Link Supervision with BFD

LTE649 QoS aware Ethernet switching

LTE664 LTE transport protocol stack

LTE713 Synchronous Ethernet

LTE800 Flexi Transport sub-module FTLB

LTE866 Fast IP Rerouting

LTE871 Transport Support Site Support Equipment

LTE875 Different IP addresses for U/C/M/S-plane




demands for the different traffic types are based on average values, while thebandwidth demand for HSPA interactive/background traffic is based on the peakbandwidth of a single user because this peak bandwidth is larger than the averagebandwidth.

The following service types are assumed to be supported for the defined transportnetwork configurations:

RT-DCH (incl. AMR voice, CS64)

NRT DCH (interactive/background traffic over DCH)

HSPA streaming with guaranteed bit rate

HSPA interactive/background with nominal bit rate

HSPA interactive/background without nominal bit rate

HSPA interactive/background traffic with and without nominal bit rate are consideredseparately because they are distinguished in air interface scheduling, although there

is no difference in transport.Service Type (RAB) Service bit rate

on Iub in DLAverage DL traffic per

BTS (MBH)

CS AMR 12.2 voice (over DCH) 12.2 kbps 23.9 Erl

CS Voice over HSPA 13.2 kbps 1.5 ErlCS 64 UDI Video 64 kbps 0.24 ErlHSPA Streaming (VoIP) GBR: 29.4 kbps 1.0 ErlPS I/B64/64 64 kbps 185 kbpsPS I/B 64/128 128 kbps 22 kbps

PS I/B 64/384 384 kbps 147 kbps

I/B HSPA Max. 42.2 Mbps 2500 kbpsTable 2: Average user traffic per WCDMA BTS

In general, traffic model values are defined per subscriber. It is assumed that eachsubscriber is using all accounted services in parallel with the assumed traffic demandper service. The average traffic values in MBH per BTS are calculated, assuming1200 subscribers per BTS, as given in Table 2: Average user traffic per WCDMA BTS.

Using RAN1004 Streaming QoS for HSPA (and RAN1262 QoS aware HSPAscheduling), voice calls via VoIP are assumed to be mapped to an HS-DSCH/E-DCHbearer with a guaranteed bit rate of 29.4 kbps (using AMR codec). Voice service splitbetween traditional CS AMR Voice, CS Voice over HSPA and VoIP users is assumedas 90:6:4 respectively.

The average user traffic demand for PS services relate to the offered traffic indownlink. To reflect the asymmetric nature of PS data services, the following UL/DLasymmetry ratio applies to the offered traffic:

Release 99 (UL/DL): 1/5.8

HSxPA Rel.6 (HSUPA/HSDPA): 1/3.9

The resulting bandwidth demand per single logical Iub (for the assumed traffic modelpresented in Table 2: Average user traffic per WCDMA BTS) is calculated using thedimensioning rules given in Dimensioning WCDMA RAN document, in Nokia SiemensNetworks WCDMA RAN, Rel. RU30 and presented in Table 3: Traffic demand on Iub




1.5.3 LTEThe average traffic of an LTE BTS that is used in this document is described in LTE

Access Dimensioning Guideline, RL 30 . The throughput is derived as the maximum ofthe average traffic of a 3 cell LTE BTS and the peak capacity of a single cell. The

bandwidth per carrier is 10 MHz in this example. The overall user plane traffic is 70Mbps in downlink, of which 2 Mbps is assumed to be VoIP with QCI-1. Within thetimeframe of this document, it is assumed that most voice calls are still handled viaGSM and/or WCDMA. The bandwidth requirements on S1 and X2, measured onEthernet level, are summarized in Table 4: LTE traffic model. The relation between S1and X2 traffic is not relevant within the scope of this document. Management planetraffic will be on average in the order of 64 kbps. 1000 kbps is provided to supportoptional tracing.

Traffic Type Bandwidth [kbps]VoIP (QCI1) 2000User plane without GBR 68000Control plane 1000IEEE1588 16Management plane 1000Total 72016Table 4: LTE traffic model

The user plane traffic in uplink, especially user plane without GBR, is considered to besmaller than in downlink.




Cisco 76xx as RNC Site Router, in Nokia Siemens Networks WCDMA RAN, SystemLibrary .

A single IEEE1588 master is deployed on the controller site.

Stand-alone OMS for WCDMA is also used. Whether this is deployed on the controllersite or in a remote network operations center is out of the scope of this document.

The iOMS for LTE is not expected to be deployed on the controller site. It is assumedto be deployed in some network operations center.

2.2 IP-based BTS connection All recommended configurations in this document are based on IP over Ethernetconnectivity for all base stations.

2.2.1 GSM Packet AbisThe GSM feature BSS21454: Packet Abis over Ethernet provides the backhaulconnectivity for the GSM BTS that is CESoPSN is not used.

Several voice user plane IP packets are multiplexed. Corresponding parameters tocontrol the amount of multiplexing are configured as defined in Table 6: GSMmultiplexing. User plane traffic for data calls is not multiplexed.

Parameter Value Comment

8 rtsl Maximum amount ofmultiplexing: 8 rtsl = 4.616 ms

4 ms -

300 bytes sufficient to multiplex 10 calls

Table 6: GSM multiplexing

2.2.2 WCDMA IP-based IubRAN74 IP-based Iub is use to connect the WCDMA BTS. In some configurations inthis document, the WCDMA voice traffic is carried separately from the HSPA NRTtraffic and subject to another bandwidth profile. As such, RAN1886 Efficient Transportfor small packets is used to reduce the bandwidth requirements for voice traffic andother user plane traffic with the same DSCP. Default parameter values for controllingthe amount of multiplexing are used; that is, in BTS, packets are buffered at most 2msbefore sent as multiplex packet and no more than 30 packets are multiplexedtogether. Packets with the same DSCP as voice are subject to multiplexing, that isDSCP 46, see Table 10: DSCP marking for WCDMA user plane.

Note: Load sharing among multiple IP addresses in the RNC is not use. All packets formultiplexing will be exchanged with the same IP addresses at BTS and RNC, allowing

the largest possible efficiency gain by multiplexing.2.2.3 LTE IP-based S1/X2

LTE traffic for both S1 and X2 interfaces is carried over IP/Ethernet.

2.3 Mobile Backhaul NetworkMultiple RATs are deployed over existing infrastructure. Therefore, the NEconfiguration has to adapt to this infrastructure. The network reference configurationsas described in this document are supported over different types and topologies oftransport networks.




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Nevertheless, in the different cases some assumptions about the transport networkhave to be made. In this document, Ethernet services are used as a commonabstraction of the network. In case of BTS chains, Ethernet services terminate beforethe first BTS in the chain. That is the connection between chained BTSs does not

belong to an Ethernet service. The connection between chained BTSs could be amicrowave link owned and operated by the mobile network owner.

The L2 network provides Ethernet connectivity among several attachment points (AP).Each attachment point can be an endpoint of several Ethernet services (ES). EachEthernet service is identified by one or several VLAN IDs. The Ethernet services thatterminate at a single attachment point must be identified by different VLAN IDs.

If an Ethernet service terminates at more than 2 attachment points, it correspondslogically to a bridged network. See Figure 1: Logical model of Ethernet service.

AP APL2

network

APES

AP AP

AP

EScorresponds

to

Figure 1: Logical model of Ethernet service

An Ethernet service may be provided with different quality guarantees regardingpacket delay, packet delay variation, and packet loss rate. Such quality attributes arenegotiated between a service provider and service user in a service level agreement(SLA).

Ethernet frames within an Ethernet service are treated similarly. Each Ethernet serviceimplements one performance class (PC). Two different performance classes areconsidered: High and Low. Within the configurations, GSM and LTE usesperformance class High, and part of the WCDMA traffic uses performance class Low.Usage of each performance class is explained in the specific configurations.The quality attributes are listed in Table 7: Attributes of performance classes. For thesake of simplicity within this document the most stringent values of all 3 radiotechnologies are used as quality attributes for performance class High.

Performanceclass name

Packetdelay[ms]

Packetdelay

variation[ms]

Packet lossrate [%]

Comment

IEEE1588 100 ms 5 ms 2% See Impact of TransportNetwork Impairments onWCDMA NetworkPerformance

GSM 15 ms 5 ms 0.001%(10 -5)

Most stringent values fromdocument TransportNetwork Solutions for BSS,RG20

WCDMA w/oHSPA NRT

10 ms -- -- No more than 10%degradation of KPIs, see indocument Impact ofTransport NetworkImpairments on WCDMA

HSPA NRT 20 ms 7 ms 0.5%




Performanceclass name

Packetdelay[ms]

Packetdelay

variation[ms]

Packet lossrate [%]

Comment

Network Performance

LTE 20 ms 5 ms 0.00001%(10 -7)

Most stringent values fromConfiguring LTE RL20 RANTransport, RL 30

High 10 ms 5 ms 0.00001%(10 -7)

Most stringent values ofIEEE1588, GSM, WCDMA,and LTE

Low 20 ms 7 ms 0.5% Same as HSPA NRTTable 7: Attributes of performance classes

The amount of data carried by an Ethernet service is limited by a bandwidth profileenforced at each attachment point of service. Same bandwidth profile is used at eachattachment point of an Ethernet service. That is, the Ethernet service provides thesame bandwidth in uplink and downlink directions of the mobile backhaul. Thebandwidth profile is defined as a peak bandwidth (PBw), guaranteed bandwidth(GBw), and burst size (BS). In this document, the burst size corresponds to 100 ms oftraffic with peak bandwidth. As an example, if the peak bandwidth is 20 Mbps, thenthe burst size is 2 Mbit. The bandwidths can be configured with a granularity of1Mbps.

Guaranteed bandwidth of the Ethernet service is always present, while peakbandwidth is provided only during normal operation. During network failure, peakbandwidth is not available. However it might be possible to provide capacity becauseof statistical multiplexing.

The bandwidth profile is enforced in each attachment point. Traffic exceeding peakbandwidth and burst size is discarded QoS unaware. That is all frames within a givenEthernet service are treated equally independent of their DSCP or PCP marking.

The PCP marking is preserved by the Ethernet service.

The Ethernet service allows carrying Ethernet jumbo frames up to 2000 bytes;therefore, no IP fragmentation is needed for LTE S1 and X2 traffic because oflimitations of the MBH network as long as the end users do not send IP packets largerthan 1500 bytes. Note that there might be other reasons causing smaller MTUs andthereby IP fragmentation.

Ethernet services terminate at a pair of routers at the controller site. As aconsequence, radio controllers and core network elements on one side and BTSs onthe other side are in different broadcast domains. There is no direct L2 connectionamong these types of elements. This pair of routers terminates the MBH network forLTE on one side and the core network for 3 radio technologies on the other side. EachEthernet service has two attachment points at the controller site. Regarding the BTS,only a single BTS site or a chain of sites are connected to one Ethernet service;therefore, each Ethernet service has three attachment points, two on the controllersite and one on the BTS.

Network reference configurations comprise three BTS sites. Two of the sites form ashort chain. Each site has two co-located BTSs with different radio technologies.Ethernet services are used to connect the BTS sites/chains and the controller site.




DN09123915Issue 03

The selection for which BTS is used as a hub for another co-located BTS is explainedin more detail in the individual configurations. See Figure 2: Common MBH topologyusing GSM BTS in each site.

RNC

APToP

master

BTS

site 3

GSMBTS

BSC

WCDMABTS

BTS

site 2

WCDMABTS

GSMBTS

BTSsite 1

WCDMABTS

GSMBTS

APL2

network

A/Iu/S1

Figure 2: Common MBH topology

Each of the radio technologies can provide voice service, but there is one radiotechnology considered for providing the majority of voice services in each of theconfigurations in this document. Usually, this radio technology is GSM. In theWCDMA+LTE configuration it is WCDMA. In the configurations, traffic of the mainvoice service is carried in a dedicated Ethernet service separate from the traffic of theother radio technology. Using separate Ethernet services eases operability andmaintainability. The voice service could use an Ethernet service with a higheravailability. At least two Ethernet services are used per BTS site or chain. The BTS ofthe same radio technology in the BTS chain can use the same Ethernet service,increasing statistical multiplexing gain and reducing the number of Ethernet services.

GSM and LTE BTS use a single VLAN for user plane traffic. A single Ethernet serviceis used for user plane traffic of a GSM or LTE BTS. This single Ethernet service has toprovide performance class High, satisfying the most stringent requirements. Also, thefull bandwidth provides GBw. In contrast, WCDMA BTS allow separating the userplane traffic into two VLANs, allowing two Ethernet services with different performanceclass. The Ethernet service with performance class Low it is possible to provide lessguaranteed bandwidth than the peak bandwidth. CAPEX/OPEX increases with thenumber of Ethernet services, whereas providing the majority of bandwidth withperformance class Low and the ability to provide less guaranteed bandwidth than thepeak bandwidth might decrease OPEX. Such traffic separation is used in theGSM+WCDMA configuration.

2.4 Quality of ServiceThe QoS for a connection through transport network is defined by packet delay,packet delay variation, packet loss rate, bandwidth and the availability that thetransport network provides. In leased line networks, these characteristics are definedin the SLA. The corresponding configuration and implementation of the SLAs in the L2cloud is out of scope of this document.

Traffic marking via DSCP or PCP is important in network elements outside of the L2network. In both uplink and downlink directions, traffic has to be shaped to match thepoliced bandwidth at the attachment point of each Ethernet service. Exceeding thepoliced bandwidth causes packet drop of arbitrary packets as the ingress policers are




assumed to operate QoS unaware. Traffic is marked according to type andimportance, the shapers and schedulers can make use of this information such thatthe requirements for the different traffic types are met.

2.4.1 Traffic Marking with DSCPThe traffic of the different radio technologies has different requirements for delay and

jitter. Different treatment aggregates and forwarding classes are defined for thedifferent traffic types in Backhaul Sharing QoS Guideline . This document defines acommon DSCP marking for all 3 radio technologies considered, see Table 8: RATservice classes to TA/FC/DSCP mapping.

TreatmentAggregate

Forwarding Class Radio AccessTechnology

Service Class DSCP(dec)

Network Control Network Control LTE synchronization plane 48

Network Control Network Control LTE Network control plane (BFD) 48

Network Control Network Control WCDMA synchronization plane 48

Network Control Network Control WCDMA Network control plane (BFD) 48

Network Control Network Control GSM synchronization plane 48

Real-Time Conversational GSM CS voice 46

Real-Time Conversational GSM control plane 46

Real-Time Conversational LTE Conversational voice (QCI-1) 46

Real-Time Conversational WCDMA CS voice (WB-AMR, AMR), CSdata (DCH RT)

46

Real-Time Conversational WCDMA Signaling Radio Bearers(SRB)

46

Real-Time Conversational WCDMA Common Transport Channels(CTrCH)

46

Assured Elastic Streaming GSM PS-data 34

Assured Elastic Streaming G SM management plane 34

Assured Elastic Streaming WCDMA control plane 26

Assured Elastic Streaming LTE control plane 26

Assured Elastic Streaming LTE IMS signaling (QCI-5) 26

Assured Elastic Streaming WCDMA PS data (DCH NRT) 26

Assured Elastic Streaming WCDMA HSPA, DCH Streaming 26

Assured Elastic Streaming WCDMA Frame Protocol Control

PDUs

26

Elastic I/B (HSPA) LTE management plane 20

Elastic I/B (HSPA) WCDMA management plane 20

Elastic I/B (HSPA) WCDMA HSPA NRT 18

Elastic I/B LTE Video live streaming (QCI-7) 12

Elastic I/B LTE Video buffered streaming(QCI-6)

10

Elastic I/B LTE Premium TCP-based data 0




DN09123915Issue 03

TreatmentAggregate

Forwarding Class Radio AccessTechnology

Service Class DSCP(dec)

(QCI-8)

Elastic I/B LTE TCP-based data (QCI-9) 0Table 8: RAT service classes to TA/FC/DSCP mapping

Due to the different congestion control mechanisms for WCDMA HSPA NRT and LTENRT traffic, the corresponding traffic has to be mapped to separate forwardingclasses. For further details, see Backhaul Sharing QoS Guideline .

2.4.1.1 DSCP marking for GSMGSM BTS does not support marking with DSCP 48, therefore uplink synchronizationplane traffic of GSM is marked with DSCP 46.

DSCP for CS and PS user plane is configured in ETP-E. DSCP for control andmanagement plane is configured in BCSU. The BSC configures the GSM BTSsaccordingly; no DSCP marking has to be configured in the GSM BTSs. Thecorresponding parameters belong to the BSC radio network managed object, seeTable 9: DSCP marking for GSM.

Parameter Service class Value

CS voice 46

PS data 34

Management plane 34

Control plane 46

Synchronization plane 46

Table 9: DSCP marking for GSM

CS voice and PS data have to be marked with different DSCPs and mapped todifferent queues in the BTS, see Backhaul Sharing QoS Guideline .

Note that ICMP traffic from BSC as well as from GSM BTS is always marked withDSCP 0.

2.4.1.2 DSCP marking for WCDMADSCP marking for the user plane is configured in the RNC. The chosen DSCP valuefor each bearer is signaled to the BTS and does not have to be configured separatelyin the BTS. The values configured in WBTS objects in the RNC are shown in Table

10: DSCP marking for WCDMA user place. is configured to 0, as the featureRAN1253 Transport QoS is not used.


0

CS voice (WB-AMR, AMR), CS data(DCH-RT), common transport channels(CTrCH), Signaling Radio Bearers

46




DN09123915Issue 03


Control plane 26

10

Management plane 20

Synchronization plane 48

Network control (BFD) 48

Site Support Equipment, see alsoChapter 2.9.3.

0

Table 12: DSCP marking for LTE

2.4.2 Traffic Marking with PCPThe ARP packets are marked with PCP 7 by the BTS of each RAT, this value is notconfigurable. IP packets are marked in BTSs according to Table 13: PCP marking.

__________________________________________________________________

NOTE

In WCDMA BTS, PCP is derived from the PHB, while in GSM and LTE, PCP isderived from the DSCP. Both DSCP 46 and 48 are mapped to the same PCP, whichis 5.

_____________________________________________________________________

DSCP PHB p-bit

ARP -- 7

46, 48 EF 5

34 AF4 4

26, 28 AF3 3

18, 20 AF2 2

10, 12 AF1 1

0 BE 0

Table 13: PCP marking

The downlink PCP marking for IP packets is provided by the edge routers according to

Table 13: PCP marking.

2.4.3 Ingress Rate Limiting in BTS internal switchThe BTS internal switch functionality provides the possibility to limit the ingress ratefor each individual port, independent of whether this is used to connect to the mobilebackhaul, to a co-located BTS, or to a chained BTS site. The FIQB transport moduleaccepts very small bursts only; therefore the ingress rate limiting functionality of theFIQB will not be used in configurations presented here. BTSs limit their own uplinktraffic. The detailed configuration is presented for the specific configurations.




2.4.4 Uplink Shaping and SchedulingBTS uplink shaping configuration depends on the network configuration. Shaping ofegress traffic takes place at two locations in the BTS. First, the BTS ’s own egresstraffic is shaped before it enters the BTS integrated switch. Then, at each physical

Ethernet interface, the aggregated egress traffic of the Ethernet switch is shaped.

Shaping

Figure 3: Shaping functionalities in BTS

Each BTS in the configurations in this document shapes its own egress traffic. TheBTS integrated switch is not used in the leaf BTS in the configurations, shaping by theBTS integrated switch is applied in hub BTSs only.

All the BTSs use a 1SP + 5WFQ scheduler when shaping its own egress user planetraffic. The DSCP to queue mapping is shown in Table 14: 1SP+5WFQ scheduler. Inthe configurations, control and management plane, traffic is handled by the sameschedulers. In GSM BTS, the same scheduler is used, whereas in WCDMA and LTE

BTS, a separate scheduler is used. The separate scheduler for WCDMA and LTEBTS uses a single FIFO queue.

The mappings from DSCP to queues are defined in Backhaul Sharing QoS Guideline .

TreatmentAggregate

Forwarding Class DSCP (dec) Queue

Network Control Network Control CS6 (48) SP

Real-Time Conversational EF (46)

Assured Elastic Streaming AF41 (34) WQ1

Assured Elastic Streaming AF31 (26) WQ2

Elastic I/B (HSPA) AF22 (20) WQ3

AF21 (18)

Elastic I/B AF12 (12) WQ4

AF11 (10)

Elastic I/B BE (0) WQ5

Table 14: 1SP+5WFQ scheduler




DN09123915Issue 03

The weights for WQ1 and WQ2 must be sufficiently large for the dimensioned amountof traffic. The weights for WQ3, WQ4, and WQ5 should correspond to the targetedbandwidth ratio among the forwarding classes when the link is fully utilized. Theweights 1:1:1 are used, providing equal bandwidth to each of the forwarding classes

and preventing starvation of any of them.The GSM BTS shapes its aggregated egress traffic per interface, independent of theVLANs used. The WCDMA and LTE BTS can either shape the aggregated egresstraffic or the traffic per VLAN.

The GSM and WCDMA BTS apply tail drop to each queue. The LTE BTS appliesweighted tail drop for the AF PHBs, where packets with higher drop precedence isdiscarded before packets with lower drop precedence.

Shaping of the aggregated traffic is described in Chapter 2.10.

2.4.5 Controlling Downlink TrafficDownlink traffic per GSM BTS can be controlled by using the Packet Abis congestioncontrol functionality, see Chapter 2.5.1: Packet Abis Congestion Control.

Downlink shaping per IP-based route in the RNC is based on internal flow control(IFC), see Chapter 2.5.2: WCDMA internal flow control.

Although an LTE SAE-GW can shape the traffic of a single bearer, it cannotshape the aggregate traffic of one LTE BTS. Note that several SAE-GWs as well asneighboring LTE BTSs might send traffic towards a single LTE BTS. Wherenecessary, downlink shaping for LTE is provided by the edge routers.

Downlink shaping and scheduling in the edge routers is configured similarly as theuplink shaping and scheduling in the BTSs For mapping of DSCPs to queues and forqueue weights see Table 14: 1SP+5WFQ scheduler. The shaping rates are describedin the specific configurations.

2.5 Congestion Control MechanismsThe radio technologies have different mechanisms to react on congestion and tocontrol the resulting amount of traffic.

2.5.1 Packet Abis Congestion ControlDifferent codecs can be applied for different GSM calls. Packet Abis congestioncontrol monitors throughput and detects packet loss and in turn, reduces the amountof traffic sent. Packet Abis congestion detection is applied in the BTS separately forboth uplink and downlink traffic. The observed congestion status is signaled from theBTS to the BSC, which reduces codec rates and the bandwidth of data calls if needed.

The threshold parameters define when congestion or a severe congestion is detected,as well as the durations of the congestion has to be present or absent before the BTStriggers action. The packet drop period values indicate how long the correspondinguplink packets may be buffered in the BTS. In case they are buffered for a longerperiod, they will already be discarded in the BTS, as they would arrive too late in theBSC and would likewise be discarded there.

Parameter abbreviation

Object Value Comment

BCF enabled




Parameter abbreviation

Object Value Comment

BCF

BCF 5000 kbps guaranteed bandwidth ofcorresponding Ethernetservice

BCF 1522 bytes

BCF 5000 kbps guaranteed bandwidth ofcorresponding Ethernetservice

BCF 92%

BCF 97%

BCF 5 5*10E-4

BCF 19 10*10E-3

BSC 4 sec 4 sec of congestion beforedeclaring congestion

BSC 10 sec 10 sec without congestionbefore declaring end ofcongestion

BSC 10 sec 10 sec of packet loss beforedeclaring this

BSC 100 sec 100 sec without packet lossbefore declaring this

BSC 25 ms

BSC 25 ms

BSC 0 ms Infinite period, no such trafficis discarded

BSC 0 ms

Table 15: Packet Abis Congestion Control Parameters




QoSPriorityMapping QoSPriority(HSPA SPI)

BTS SchedulingWeight

15 014 012 4013 013 013 011 357 153 610 306 102 59 255 91 28 204 80 10 1

Table 17: WCDMA SPI definitions

In the downlink direction, HSDPA congestion control is used to adapt the bit rate ofthe NRT HSPA bearers in case less than peak bandwidth is available in an Ethernetservice used for HSDPA NRT.

The congestion control policy in the BTS is set to ON for SPIs 0 to 11. For SPIs 12 to15 the congestion control policy is set to OFF. Congestion control will not be appliedto conversational, streaming, nor signaling bearers on HSDPA. The congestion controlpolicy for streaming bearers is set to OFF instead of controlling to GBR, otherwise theaverage delay of streaming and NRT traffic will be used in the congestion control.However, streaming and NRT traffic are mapped to different PHBs and queues inMBH and are expected to experience much lower delay. The average delay would notprovide useful information anymore.

HSDPA congestion control is operated with default value for the threshold parametersthat is a value of 50 ms for Thmin and 250 ms for Thmax.

2.5.4 HSUPA congestion controlHSUPA congestion control is used in uplink with default values, see Table 18: HSUPA

congestion threshold parameters.Parameter Value

50 ms

70 ms

100 ms

Table 18: HSUPA congestion control threshold parameters




DN09123915Issue 03

2.5.5 TCP congestion control for LTECongestion of LTE traffic is handled by the end user TCP congestion control. Notethat traffic carried via UDP and without congestion control mechanisms will not beaffected. There is no subscriber differentiation, bearers with both QCI8 and QCI9 are

marked with DSCP 0 and will be mapped to the same queues. Therefore, thesepackets are treated identically in the transport network.

2.6 RF sharingRF sharing allows using the same RF module for two system modules of differentradio technologies. When RF sharing is used, the two system modules aresynchronized via RP3-01. No additional synchronization via the transport interfacesmust be done.

The system module of one specific radio technology is always acting as clock master.In Table 19: Synchronization roles for RF sharing, the roles clock slave and clockmaster are indicated for the different RAT combinations.

RAT combination Clock master Clock slave

GSM+WCDMA WCDMA GSM

GSM+LTE LTE GSM

WCDMA+LTE not supported currently

Table 19: Synchronization roles for RF sharing

Although RF sharing provides CAPEX and OPEX reductions for a single RANdeployment, it is not a prerequisite from a shared transport perspective. RF sharingwill be used exemplarily in this document in the GSM+LTE configuration to show theimpact on synchronization. Note that this configuration could also be deployed withoutRF sharing, and the GSM+WCDMA configuration could also be deployed with RF

sharing.2.7 Physical connectivity at BTS site

Optical Ethernet is used to connect the hub BTS on each site to the backhaul network.

For co-located BTSs and for chaining another BTS site, electrical Ethernet is used. Tokeep configurations as homogenous as possible, 1000Base-T is used, even if onsome interface 100Base-T would be sufficient regarding the traffic volume. AllEthernet interfaces are configured to detect speed and duplex automatically. GSMBTS i s also configured to advertise 1000 Mbps on electrical interfaces.

2.8 Synchronization on BTS siteIn general, the hub BTS on each site acts as IEEE1588 slave, providingsynchronization to a co-located BTS via Synchronous Ethernet (preferred) or via anE1 line without traffic. WCDMA FTIB transport module cannot regenerateSynchronous Ethernet, so an additional E1 line is deployed. Alternatively, a dedicatedIEEE1588 slave per BTS can be used.

In case RF sharing is used, the synchronization on a BTS site is distributed via theRP3 interface instead of Synchronous Ethernet.




DN09123915Issue 03

The route between the primary router and the BTS is bound to a BFD session. In casethe BFD session is down, the traffic is redirected via the other router. On the WCDMAand LTE BTS, the features RAN2440 and LTE866 Fast IP Rerouting are used,respectively.

The management planes are separated from the other traffic. Therefore, on each site,2 VLANs are used for the WCDMA traffic.

AP

BTSsite1

LTEBTS

WCDMABTS

AP

L2network

10.3.2.1/2910.3.1.1/29

10.3.2.2/2910.3.1.2/29

10.0.1.2/30

10.0.1.1/3010.3.2.6/2910.3.1.6/29

Router1

Router2

B F D20.3.1.6/29

Figure 4: Routing configuration for BFD-triggered static routes

The site routers are connected to an additional VLAN. This connection is used toreroute traffic via the other site router in case the direct connection between routerand BTS is broken.

One of the routers is considered as primary router for this BTS site. In this example,this is Router1. The primary router might be different for different sites to distribute theload in normal operation.

As indicated in Figure 4: Routing configuration for BFD-triggered static routes, a BFDsession is configured between the primary router and the BTS site. More specifically,the BFD session is configured to the VLAN for WCDMA user, control, andsynchronization planes. High-priority traffic is carried here and correspondingly, goodperformance objectives are required from the underlying Ethernet service. Hencethere should be no congestion impacting the BFD session.

A corresponding configuration is done for the LTE BTS, with the BFD sessionconfigured on the VLAN for LTE user and control plane. The following explanations forWCDMA apply for the routing configuration of the LTE BTSs as well.

In Router1, the static routes towards the WCDMA BTS are bound to a BFD group.The BFD session on the VLAN for WCDMA user, control plane and synchronizationplane is an active session. The other BFD sessions are passive ones.

Both routers exchange the status of their routes towards the BTS via OSPF, therebyavoiding an additional BFD session between the BTS and Router2 as well as potentialrouting loops. The interfaces on the two routers used for the interconnection are

configured to the same OSPF area. The static routes towards the BTS areredistributed to the OSPF area on both routers. OSPF convergence times do notimpact the switchover times, as OSPF is used only to reinstall routes after recoveryfrom a failure. No other routers are connected to this OSPF area in the configurationsin this document.

On Router1, the static routes need to have preference over the routes learned viaOSPF, whereas on Router2 the routes learned via OSPF have preference. Therefore,the administrative distance of the static routes in Router1 is set to 1 and Router2 is setto 120. The administrative distance of OSPF is globally set in both routers to 110. Theadministrative distances for static routes in Router1 and for OSPF are the default




settings; hence, no explicit configuration is needed. On Router2, the administrativedistance has to be set explicitly for each of the routes; the static routes becomefloating static routes .

An overview of the downlink routes is provided in Table 20: Static route configurationfor downlink traffic. Traffic for WCDMA BTS OAM subnet – 20.3.1.0/29 – is routed viathe corresponding transport management plane address – 10.3.1.6.

Router Destinationaddress

Next-hopaddress

Administrativedistance

BFD group Status inBFD group

Router1 20.3.1.0/29 10.3.1.6 1 “Site1” Passive

10.3.2.6/32 10.3.2.6 1 “Site1” ActiveRouter2 20.3.1.0/29 10.3.1.6 120 - -

10.3.2.6/32 10.3.2.6 120 - -Table 20: Static route configuration for downlink traffic

In the WCDMA BTS, a BFD session is configured for the VLAN for user, control, andsynchronization plane. This session is used on all traffic planes to define a static routetowards Router 1; static routes with lower preference are configured towards Router 2.

A default route is configured on the management plane VLAN towards Router 2. Thisis used as a last resort. In case of misconfigurations, the BTS can still be managed viathis route and the configuration can be corrected. Preference of this route does notmatter as it is the least preferred route due to the prior longest prefix matching. Theparameters in the WCDMA BTS are summarized in Table 21: WCDMA BTS uplinkroute configuration.

Traffic plane Destination address Next-hopgateway

Preference BFDsession

BTS OAM Netact, OMS, OMU 10.3.1.1 5 1

0.0.0.0/0 10.3.1.2 1 -WCDMA user,control,synchronizationplane

RNC user plane address,RNC control planeaddress, IEEE1588master

10.3.2.1 5 1

RNC user plane address,RNC control planeaddress, IEEE1588master

10.3.2.2 10 -

Table 21: WCDMA BTS uplink route configuration

The BFD session is configured with parameters as shown in Table 22: WCDMA BTSBFD session parameters. Corresponding parameters have to be configured in

Router1, especially the intervals and the amount of packets lost before the sessionsare considered down should match the values in the BTS.

Parameter Value comment10.3.2.1 Router13 0.9 seconds to recognize

route interruptionEmpty Not needed1 -10.3.2.6 -




DN09123915Issue 03

Parameter Value comment3784 Default

-300ms -

Default300ms -

Table 22: WCDMA BTS BFD session parameters

2.9.2.2 Routing configuration with HSRP/VRRPWhen using HSRP/VRRP to provide a single virtual IP address as next-hop gatewayto the GSM BTS, one of the site routers is considered the primary router (HSRP isconfigured such that this router is also the HSRP master in normal operation). TheHSRP messages are exchanged via the MBH network. A router failure, a link break atthe attachment point or a connectivity break inside the L2 network between these twocontroller site attachment points will trigger the HSRP slave to become HSRP master.

In the case of a router failure or a link break, the corresponding router will not continueto send downlink traffic to the BTS. A connectivity failure inside the L2 backhaulnetwork might not be recognized by the routing engine, even if the HSRP role haschanged. In this case, the router will continue to send downlink traffic to the BTS, andtraffic will be lost. The most common error cases are router or link breaks at theattachment points, which will be handled correctly. The risk of lost downlink traffic dueto unrecognized connectivity breaks can be mitigated by different technical meanssuch as tearing down interfaces in case of a connectivity break in an Ethernet service.Such means are vendor specific and are therefore not described in this document.

AP

BTSsite1

GSMBTS

WCDMABTS

APL2

network10.2.1.2/2910.2.2.2/29

10.3.3.2/2910.3.2.2/2910.3.1.2/29

10.2.1.3/2910.2.2.3/29

10.3.3.3/2910.3.2.3/2910.3.1.3/29

10.2.2.6/2910.2.1.6/29

10.2.2.1/2910.2.1.1/29

10.3.2.6/2910.3.3.6/29

10.3.1.6/29

Router1

Router2

HSRP

20.3.1.6/29

10.3.3.1/2910.3.2.1/2910.3.1.1/29

Figure 5: Routing configuration for HSRP

This setup is explained in more detail subsequently for co-located GSM and WCDMABTS. Routing in an LTE BTS can be configured similarly to a WCDMA BTS, exceptthat there is just one VLAN for user plane traffic.

IP addresses examples for this configuration are summarized in Table 23: VLAN andIP address overview.

Traffic plane VLANId

BTS IPaddress

Router1 IPaddress

Router2 IPaddress

Virtualrouter IPaddress

GSM management plane 501 10.2.1.6/29 10.2.1.2/29 10.2.1.3/29 10.2.1.1/29




Traffic plane VLANId

BTS IPaddress

Router1 IPaddress

Router2 IPaddress

Virtualrouter IPaddress

GSM user, control,synchronization plane 1001 10.2.2.6/29 10.2.2.2/29 10.2.2.3/29 10.2.2.1/29

WCDMA managementplane (trsp)

1501 10.3.1.6/29 10.3.1.2/29 10.3.1.3/29 10.3.1.1/29

WCDMA OAM subnet n/a 20.3.1.5/29 3 20.3.1.6/29 4

n/a n/a n/a

WCDMA high-priority user,control, synchronizationplane

2001 10.3.2.6/29 10.3.2.2/29 10.3.2.3/29 10.3.2.1/29

WCDMA low-priority userplane

2501 10.3.3.6/29 10.3.3.2/29 10.3.3.3/29 10.3.3.1/29

Table 23: VLAN and IP address overview

Two HSRP groups 5 are configured per GSM BTS, one for each VLAN. Additionalgroups are configured for the WCDMA or LTE BTS. The primary router is the HSRPmaster under normal conditions. HSRP preempt is used to move the master role fromthe secondary to the primary router if this becomes available again after failure.

Table 24: HSRP configuration summarizes the HSRP configuration of Router1 andRouter2 regarding the GSM BTS on site1. A similar configuration has to be replicatedfor each GSM BTS. In case the traffic shall be shared among both routers in normaloperation, the master role should be on Router1 for half of the BTS sites and on

Router2 for the other half of the BTS sites.Router VLAN

IDTraffic plane IP address HSRP

Group Priority Virtual Router IP

Router1 501 GSMmanagementplane

10.2.1.2/29 1 110 10.2.1.1/29

1001 GSM user,control,synchronizationplane

10.2.2.2/29 2 110 10.2.2.1/29

Router2 501 GSMmanagement

10.2.1.3/29 1 90 10.2.1.1/29

3 mPlaneIpAddress 4 ftmIpAddr 5 One of the two HSRP groups can be configured as master and the other HSRPgroup to follow the state of the master group. This optimization has not beenexplained in detail for the sake of readability.




DN09123915Issue 03

Router VLAN Traffic plane IP address HSRP

plane

1001 GSM user,control,synchronizationplane

10.2.2.3/29 2 90 10.2.2.1/29

Table 24: HSRP configuration

2.9.3 IP address for SSE As a typical example of site support equipment, NSN Green Energy Controller isinstalled on each BTS site. This device allows monitoring and controlling additionalequipment to provide energy on a BTS site. This controller can be reached via asingle IPv4 address from a management system such as Netact. In a WCDMA BTS,this address can be taken from the OAM subnet of the BTS. In this document, a /29subnet has been used and six IP addresses are available in this subnet. In an LTE

BTS, a dedicated OAM subnet has to be defined, which would then contain the IPaddresses for the management plane application as well as for SSE. Thecorresponding traffic will be carried together with the management plane traffic of theBTS to which the Green Energy Controller is connected.

The Green Energy Controller does not use VLAN tags, but as the traffic is routedthrough the BTS there is no problem to use a VLAN towards the backhaul withouthaving to use VLANs for the directly connected SSE. The traffic volume is considerednegligible.

The Green Energy Controller is connected to the port labeled ‘BBU’ (battery backupunit) of the WCDMA or LTE system module. In the IP filtering rules, the restrictedmode for LMP is switched off. This adds an exception rule to the firewall, allowingtraffic from any address in the BTS OAM subnet to be received from any of the ports

for local management and site support equipment. A route is configured for themanagement system of the Green Energy Controller using the same next hop addressas other management plane traffic.

In a GSM BTS, the Green Energy Controller would be connected to one of thetransport ports; there is no BBU port as in the WCDMA and LTE BTS.

The LTE BTS allows remarking the DSCP of traffic from the SSE. Although the GreenEnergy Controller marks its egress traffic with DSCP 0, the LTE BTS ensures thisvalue by configuring the DSCP for the traffic type SSE to 0. In case the Green EnergyController is connected to a WCDMA, such marking cannot be enforced. Remarking ofdownlink SSE traffic is done in the edge routers.

In the WCDMA+LTE and GSM+LTE configuration, the SSE is connected to the hubBTS on a site. This has the slight benefit that connectivity of SSE depends on as fewBTSs as possible. In the GSM+WCDMA configuration, the GSM BTS is used as hubBTS, but on BTS site 2, all Ethernet ports are used already for transport purposes.Therefore in this configuration, the WCDMA BTS, that is the leaf BTS on each site areused to connect SSE.

2.9.4 Controller siteCisco76xx based controller site solutions are used. For radio technology specific IPconfigurations refer to:




GSM: BSC TRANSPORT SITE SOLUTION, RG20 Mother Document,Scenarios and Requirements and BSC TRANSPORT SITE SOLUTION RG20Daughter Document External L2/L3 Equipment

WCDMA: Configuring WCDMA and Flexi Direct Transport and RAN1884:Cisco 76xx as RNC Site Router, in Nokia Siemens Networks WCDMA RAN

LTE: Configuring LTE Transport

2.10 Traffic Aggregation on BTS siteThe traffic at the BTS site is aggregated by one of the BTSs by the BTS integratedEthernet switch. This hub BTS aggregates the traffic from both a co-located BTS aswell as from a chained BTS site (optional). Therefore, this hub BTS requires 3Ethernet interfaces. The details of the connectivity and aggregation are shown in thefollowing chapters.

The BTS integrated Ethernet switch of the GSM and LTE BTSs is able to switchEthernet frames of up to 1632 bytes. This allows configuring of an MTU of 1560 bytesfor LTE and thereby to avoid IP fragmentation. In the WCDMA BTS, Ethernet switchframes of up to 1522 bytes 6 can be handled. The MTU in co-located BTS must be setto 1500 bytes.

The egress traffic of the hub BTS itself should be shaped. This traffic together withother BTSs traffic, which is shaped individually at origin, is aggregated in the hubBTS's Ethernet switch.

At least two Ethernet services are used per BTS chain in the configurations in thisdocument. Therefore the BTS integrated switch cannot be used to shape the uplinktraffic, as it can shape the traffic per interface only. Traffic bursts, even when short,cause delay to high-priority packets. To avoid delay, the BTS integrated switches areconfigured to schedule the traffic at each of its interfaces in a QoS aware manner, thecorresponding shaping rate is line rate (1 Gbps). The prioritization of traffic is achieved

by classifying the traffic to queues based on PCPs and by using the default mappingof PCPs to queues.

Note that the BTS integrated switch functionality is not used in the leaf BTS on a site.

VLAN tags are preserved by the BTS integrated Ethernet switches. Filtering Ethernetframes at external ports based on VLAN IDs is switched on for the WCDMA and LTEBTSs acting as hub BTS. This limits broadcast storms. The integrated Ethernet switchin the GSM BTS does not support such filtering.

The exemplary VLAN IDs used in this document are shown in Table 25: VLAN IDs.

Site GSMmanagement

plane

GSM user,control,

synchronization plane

WCDMAmanagement

plane

WCDMA(high-

priority)user,

control,synchroniza

tion plane

WCDMAlow-priorityuser plane

LTEmanagement

plane

LTE user,control,


1 501 1001 1501 2001 2501 3001 3501

2 502 1002 1502 2002 2502 3002 3502

6 Switching of Ethernet frames of up to 1632 bytes will be supported in future releasesof WCDMA RAN.




DN09123915Issue 03

Site GSMmanagement

plane

GSM user,control,


WCDMAmanagement

plane

WCDMA(high-

priority)user,

control,


WCDMAlow-priorityuser plane

LTEmanagement

plane

LTE user,control,


3 503 1003 1503 2003 2503

Table 25: VLAN IDs

Note that VLAN filtering is applied in the GSM+LTE and in the WCDMA+LTEconfiguration. WCDMA (in WCDMA+LTE configuration) and LTE BTSs in the BTSchain with sites 2 and 3 are connected to the same VLANs. GSM BTSs always use adedicated VLAN.

2.11 SecurityIPsec is not considered in this release of the document. In case IPsec is used, a largeroverhead due to IPsec encapsulation has to be considered. Especially, shapingtowards bandwidth profiles at attachment points should be done after IPsecencapsulation such that the larger overhead is handled correctly and packet discard atthe attachment point is avoided. If IPSec would be used, it must be terminated in eachBTS individually. Hub BTSs cannot act as IPSec GW for a whole site.

For WCDMA and LTE BTS, the automatic firewall features are used. No specificconfiguration is needed.

2.12 Auto-configuration Auto-connection and auto-configuration can be used to deploy additional WCDMA andLTE BTS in the field. As the hub BTSs are configured as Ethernet switches, co-located or chained BTSs are connected via Ethernet with the edge routers. The edgerouters have to be configured as DHCP relay, relaying the DHCP requests to a

suitable OMS.2.12.1 Measurements

The BTSs are configured to monitor delay and delay variation of the transportnetwork.

For GSM, the packet Abis delay measurements are used (BSS30395: Packet AbisDelay Measurement), for WCDMA and LTE, TWAMP-light is in use(RAN1900/LTE574 IP Transport Network Measurement). TWAMP-light refers toRFC5357, appendix I.

The Cisco routers on the controller site do not provide sufficient support to act asreflectors for the measurements, see IP Transport Monitoring with StandaloneDevices . Therefore for WCDMA, the measurements are done between the BTS and

RNC and for LTE a dedicated device is used at the edge router site.The measurements are performed separately for the BTS of each technology, therebyallowing independent monitoring.

2.12.1.1 GSM measurementsWhen the measurements are activated in the BSC, the BTS sends a UDP packet tothe BSC every 5 seconds. These packets are reflected at the BSC and the BTSmeasures the round trip time. The BTS reports each measurement to the BSC, whichcan then derive minimum, average, and maximum round trip time and minimum andmaximum round trip time variations.




Except for starting the measurements on the BSC, there are no parameters to beconfigured. The BTS will send the UDP packets to the user plane IP address of theBSC and will use the corresponding DSCP marking.

2.12.1.2 WCDMA measurementsThe BTS is configured to send TWAMP messages (on top of UDP) to the RNC, whichare reflected there and the BTS can take the measurements. The BTS is configured totake the measurements separately for the high and low-priority user plane. Typicalmessage sizes for the different traffic planes are used; the destination port (dstPort) isthe one for UDP echo at the RNC. On the high-priority user plane, there are actuallytwo different DSCPs for voice and for DCH NRT traffic. Just one measurement is usedwith the DSCP corresponding to voice, allowing monitoring whether the requiredperformance objectives for voice are met.

For both user planes, two lost measurement packets will trigger an alarm. In 15-minute measurement interval, 450 measurements are done per measurement. Twolost packets correspond to a packet loss of 0.44%.

If the round trip time for the high priority user plane exceeds 20 ms (twice the delay asindicated in Table 7: Attributes of performance classes), the RTT alarm is raised. Thisalarm indicates that the performance objective for packet delay of the Ethernet servicehas been violated. For the low-priority user plane, the threshold is set to a valueslightly smaller than the threshold for HSDPA CC. Round trip time has to be largerthan the threshold for one minute to raise the alarm. Therefore sporadically exceedingthe bandwidth with a corresponding increase in the delay does not trigger the alarm.The threshold for HSDPA CC is 50 ms, for the round trip time alarm, a value of 45 msis used assuming that mostly one of the two directions experiences a delay. Thisalarm indicates that the backhaul link has been congested over an extended period oftime, indicating that the backhaul connection does not provide sufficient capacity.

In totality, 1 message per second is sent, meaning that there will be one message per2 seconds for each of the two measurements. The settings are summarized in Table26: WCDMA IP measurements.

Traffic plane messageSize

destPort

DSCP

plrAlarmThresho

ld

rttAlarmThresho

ld

twampSourcePo

rt

twampMessageR

ate

high-priorityuser plane

100bytes

7 46 0.44% 20 ms 49151 RATE_1(1msg persecond)

low-priorityuser plane

1000bytes

7 18 0.44% 45 ms

Table 26: WCDMA IP measurements

The IP addresses used are the corresponding user plane addresses on both BTS andRNC.

2.12.1.3 LTE measurementsThe LTE BTS is configured to send TWAMP messages (on top of UDP) to a dedicateddevice at the site of the edge routers. This device reflects the UDP messages and theBTS can take the measurements. The edge routers might have limitations in replyingto UDP echo; therefore, a dedicated device is used. Here, an Accedian Metronodedevice is used; see IP Transport Monitoring with Standalone Devices . It is connected




DN09123915Issue 03

to both edge routers in a redundant way. It is acting as UDP echo server only; it doesnot perform measurement itself. The setup is shown in Figure 6: Accedian Metronodeas measurement device for LTE .

AP

BTSsite1

LTEBTS

APL2

network

Router1

Router2

AccedianMetronode

TWAMP/UDP UDP echo

Figure 6: Accedian Metronode as measurement device for LTE

The configuration is similar to the one for WCDMA, see Chapter 2.12.1.2: WCDMAmeasurements. For the low-priority user plane, the threshold is based on the end toend delay budget for NRT traffic, which is 300 ms. Leaving some delay budget for airinterface scheduling, the alarm will be raised when the RTT exceeds 200 ms. It isassumed that only one of the two directions experiences a delay at a given time, seeTable 27: LTE IP measurements.

Trafficplane

Messagesize

destPort DSCP plrAlarmThreshold

rttAlarmThr eshold

twampSour cePort

twampMessageRate

high-priorityuser plane

100 bytes 7 46 0.44% 20 ms 49151 RATE_1(1msg persecond)

low-priorityuser plane

1000bytes

7 0 0.44% 200 ms

Table 27: LTE IP measurements

As the LTE BTS transmits all user plane traffic on a single VLAN, the measurementsfor both high-priority (QCI1) and low-priority (QCI6-9) traffic are performed on thesame VLAN and using the same IP addresses at each of the peers.




3 GSM and WCDMA3.1 Recommended network configuration description

This reference configuration describes a configuration for a GSM and a WCDMA RANover a shared mobile backhaul network. Both RATs use IP/Ethernet for backhaul

The main characteristics of the network considered in this case are as follows:

Backhaul network overview : The backhaul network provides L2 connectivitybetween controller site routers and BTS sites. Three Ethernet services areused per BTS site, one for high and one for low-priority WCDMA traffic andone for GSM traffic. The backhaul network is agnostic concerning theunderlying technology used to provide the L2 services. A typicalimplementation of such a transport service is VPLS using an MPLS basednetwork.

Backhaul network sharing : The network is shared by both GSM andWCDMA RAN. There might be additional services using the network, butthere is guaranteed capacity allocated to the mobile network. Thedimensioning of the guaranteed capacity should follow the mobile networkdimensioning.

Synchronization : An IEEE1588 master is located on the controller site. TheGSM BTS on each site is synchronized via IEEE1588 and synchronizes theco-located WCDMA BTS with SyncE.

Network redundancy : It is assumed that the transport network featuresinherent redundancy, transparently protecting the mobile traffic againstfailures inside the network.

Controller site redundancy: Controller site routers are doubled forredundancy. The radio controller connections to the network are redundant,

whereas for each BTS the traffic is carried over a single link in the last mile.The redundancy solution for the radio controllers is the usual, HSRP/VRRPbased one.

Backhaul network bandwidth: The backhaul network supports bandwidthprovisioning for the BTSs. The provisioned bandwidth is assumed to bealways sufficient for the WCDMA traffic subject to CAC and for the controlledamount of GSM traffic. The provisioning of bandwidth is transparent to themobile network; it is considered part of the network operation.

Backhaul network QoS: The backhaul network is able to prioritize trafficbased on VLAN p-bits.

VLAN usage: VLANs are deployed in the backhaul network to separate the

BTS broadcast domains and to facilitate mapping of traffic to Ethernetservices. At BTS, management plane is separated to its own VLAN. In thisconfiguration, VLANs are configured to RNC, BSC, and controller site routers.

3.1.1 General configurationIn this recommended configuration, three Ethernet services per BTS site are used;each Ethernet service providing a single performance class. For the BTS chain, twosets of Ethernet services terminate at the attachment point, thereby hiding the accessnetwork topology at the controller site. This is shown in Figure 7: Several Ethernetservices with single performance class .




DN09123915Issue 03

RNC

AP ToPmaster

BTSsite 3

WCDMABTS

GSMBTS

BSC

BTSsite 2

WCDMABTS

GSMBTS

BTSsite 1

GSMBTS

WCDMABTS

AP

L2network

A/Iu

Figure 7: Several Ethernet services with single performance class

GSM is considered the fallback network for voice services and uses a separateEthernet service. The GSM BTS is used as hub BTS on each of the sites, thus theavailability of the GSM BTS on a site does not depend on the availability of any other(aggregating) BTS.

Two of the Ethernet services per BTS site provide performance class High and theremaining one performance class Low. The Ethernet service with performance classLow is used for HSPA NRT traffic and for WCDMA management plane traffic. All theother traffic of a site is carried within the Ethernet services with performance classHigh. That is all GSM traffic including management plane in one Ethernet service withperformance class High and all WCDMA RT, DCH NRT, and control plane traffic inthe other Ethernet service with performance class High.

The Ethernet services with performance class Low are dimensioned such that the

average bit rate is provided as guaranteed bandwidth and the peak bit rate is providedas peak bandwidth. Some additional bit rate is provided for the management plane.For Ethernet services with performance class High the bandwidth is provided asguaranteed bandwidth equal to peak bandwidth, separately for WCDMA and GSMtraffic.

For the traffic amount for downlink, see Chapters 1.5.1 and 1.5.2.

Traffic type Average [kbps] Peak [kbps]

GSM CS user plane n/a 1500

GSM PS user plane n/a 2100

GSM control plane n/a 400

GSM management plane n/a 64

IEEE1588 16 16

WCDMA control plane 507 507

WCDMA user plane RT + DCH NRT 3701 3701

WCDMA CCH 66 66





WCDMA user plane HSPA NRT 4418 41200

WCDMA management plane 64 n/a

Table 28: GSM and WCDMA traffic amount

For GSM traffic, 1500 kbps + 2100 kbps + 400 kbps + 64 kbps + 16 kbps = 4080 kbpsare needed as guaranteed bandwidth on the Ethernet service with performance classHigh. For WCDMA, 507 kbps + 3701 kbps + 66 kbps = 4274 kbps are needed. For theWCDMA, Ethernet service with performance class High, using the 1 Mbps granularityfor bandwidth profiles, 5 Mbps of guaranteed bandwidth are used for these Ethernetservices.

For the Ethernet service with performance class Low, there is 4418 kbps + 64 kbps =4482 kbps average throughput, therefore 5 Mbps of guaranteed bandwidth is required.The peak throughput of the user plane is 41.2 Mbps; an overall capacity of 45 Mbpsleaves sufficient room for the peak user plane throughput and more than average

throughput for the management plane. The peak bandwidth is set to 45 Mbps.The guaranteed bandwidth and peak bandwidth values are summarized in Table 29: GSM/WCDMA information rates.

Ethernet service Performanceclass

Guaranteedbandwidth [Mbps]

Peak bandwidth[Mbps]

ES 1 High 5 5

ES 2 High 5 5

ES 3 Low 5 45

Table 29: GSM / WCDMA information rates

These specific rates are used to determine shaping rates and parameters for CAC.

3.1.2 Feature usageThe most relevant features for deploying GSM and WCDMA over a shared backhaulnetwork in this recommended network configuration are listed below:

3.1.2.1 GSM BSS101417 QoS aware Ethernet Switching

BSS21439 Packet Abis Sync. ToP IEEE1588v2

BSS101459 Full GE support for FIYB/FIQB

BSS21445 Packet Abis Congestion Reaction BSS21454 Packet Abis over Ethernet


BSS30450 Packet Abis Synchronous Ethernet

3.1.2.2 WCDMA RAN992 HSUPA Congestion Control

RAN1110 HSDPA Congestion Control




DN09123915Issue 03




RAN1886 Efficient Transport for small IP packets


3.2 RAN parameters for the configuration3.2.1 General

The available bandwidth is statically divided between GSM and WCDMA per site. Thetraffic of each of the radio technologies is shaped independently so as not to exceedEthernet service capacity. Only WCDMA traffic is carried on the Ethernet services withperformance class Low and is shaped separately. As a consequence, no shaping toEthernet service bandwidths is applied by the BTS internal Ethernet switch in theuplink direction. Within this configuration, there are no bottlenecks in downlinkdirection as seen from the hub BTS, therefore, there is also no shaping of the BTS indownlink direction to a rate smaller than line rate.

The burst size of the Ethernet services with performance class High is 500 kbit, of theEthernet services with performance class Low is 4.5 Mbit. As each Ethernet service isused by a BTS of one RAT only, the bursts can be controlled separately per RAT.

On BTS site 2, all three Ethernet interfaces of the GSM BTS acting as hub are used,leaving no possibility to connect SSE. Therefore, SSE is connected to the WCDMABTS and this is done consistently on all BTS sites.

3.2.2 ShapingThe capacity of the Ethernet services with performance class High is 5 Mbps andprovisioned as guaranteed bandwidth.

The downlink GSM and WCDMA traffic is controlled by BSC and RNC resp. The GSM traffic of both VLANs in total is monitored in the BTS and once the

threshold or packet loss thresholds are exceeded for a predefined time, thetraffic volume is reduced, see Chapter 2.5.1: Packet Abis Congestion Control.No shaping of GSM traffic in the edge router is needed.

The WCDMA high-priority user plane traffic including common channels doesnot exceed 3770 kbps on Ethernet level, corresponding to 3370 kbps on IPlevel. At least 435 kpbs are needed for signaling traffic, no reservation isneeded for management traffic for this BTS as the management plane trafficis carried together with the low-priority user plane. In total, at least 3805 kbpsof committed bandwidth is needed. The RNC shapes the traffic accordingly,as committed bandwidth of this IP based route is configured to 3900 kbps andby internal flow control (IFC) is activated. NPGE load sharing cannot be used,otherwise shaping via IFC would not be available.

The WCDMA low-priority traffic is shaped in the RNC by using IFC to 40000kbps on IP layer, corresponding to about 41000 kbps on Ethernet layer. Thisleaves 4 Mbps for management plane traffic. Note that the aggregate ofmanagement plane traffic and low-priority user-plane traffic is not shaped.HSPA congestion control is used to react in case the peak bandwidth of theEthernet service capacity is not available.




Two IP based routes for each WCDMA BTS are configured in the RNC as shown inTable 30: IP based route configuration. These values are configured on IP layer, seeTable 3: Traffic demand on Iub per single BTS.

Parameter name IPBR for highpriority traffic

IPBR for lowpriority traffic

Comment

3900 40000 Used for calladmission control

0 1000 Maximum valuepossible, but noimpact on shaping

435 0

ON ON

4500 41000Table 30: IP based route configuration

In uplink direction, the traffic is shaped to avoid packet drop by the policers at theattachment point.

The parameters below are measured on Ethernet level.

Each BTS shapes its own uplink traffic. The available line speed of the last mile(1Gbps) is larger than the sum of peak bandwidth values of the Ethernet services.The BTS integrated switch is used for traffic prioritization only see Chapter 2.10: Traffic Aggregation on BTS site.

The traffic is aggregated in the GSM BTS, which has limited buffer space for Ethernetframes in its integrated switch. To avoid packet drops, the BTS should not generatebursts in uplink direction.

The GSM BTS shapes all its uplink traffic on interface level. Uplink traffic shaping isswitched on by setting the parameter ULTS to shaping-committed (1). The parameterULCIR is set to 5000 kbps.

Parameter name Value Comment

1522 maximum size of a singleEthernet frame

5000 All traffic planes together

shaping-committed (1)

Table 31: GSM BTS uplink shaping parameters

The WCDMA BTS shapes its traffic per VLAN; there is no similar mechanism as theinternal flow control in the RNC to limit the amount of high-priority user plane traffic inthe uplink direction. The uplink management plane and low-priority user plane trafficare shaped separately. The shaping rate is set to the remaining capacity of theEthernet service after provisioning capacity for the user plane.




DN09123915Issue 03

Parametername

high-priorityuser, control,synchronizati

on plane

low-priority

userplane

managementplane

Comment

True (1) True (1) False (0) 6-queue schedulers forVLANs with user planetraffic, single queue formanagement plane

1522 1522 1522

5000 41000 4000

4000 41000 n/a Used for CAC: note that asmall reservation is neededfor frame protocol controlPDUs

Path Configured per BTS, shapingper VLAN

false(0) Ethernet overhead isconsidered

Table 32: WCDMA BTS uplink shaping parameters

The configured bandwidth and the location of the shapers are summarized in Figure 8: Shaping for GSM and WCDMA. The lower part of the diagram shows whether shapingis done per interface or VLAN in the BTS, the corresponding shaping rate, whichVLANs are mapped to which Ethernet service, the performance class, guaranteed andpeak bandwidth of the Ethernet services, and the shaping rates in the RNC. Thisconfiguration is used on each BTS site.

AP

BTSsite1

GSMBTS

WCDMABTS

AP

L2network

GSM U/C/SGSM M

WCDMA Uh/C/S

WCDMA UlWCDMA M

Router1

Router2

5Mbps bothVLANs

5Mbps bothVLANs

(PAbis CC)5Mbps

4Mbps

41Mbps

4.5MbpsIFC at RNC

Phys IF

VLAN

VLAN

VLAN

RNC

ToPmaster

BSC

ES3 PC Low5/45Mbps

E S 2 P C

H i g h

E S 1 P C

H i g h

ES2 PC High5/5Mbps

ES1 PC High5/5Mbps

41MbpsIFC at RNC

no shaping

E S 3 P C

L o w

Figure 8: Shaping for GSM and WCDMA




DN09123915Issue 03

4 GSM and LTEThis reference configuration describes a configuration for a GSM and an LTE RANover a shared mobile backhaul network. Both RATs use IP/Ethernet for backhaul.

The main characteristics of the network considered in this case are:

Backhaul network overview : The backhaul network provides L2 connectivitybetween controller site routers and BTS sites. Dedicated Ethernet servicesare used per RAT, and the same performance class is used for all traffic. Thebackhaul network is agnostic to the underlying technology used to provide theL2 services. A typical implementation of such transport service is VPLS usingan MPLS based network.

Backhaul network sharing : the network is shared by both GSM and LTERAN. There might be additional services using the network, but there isguaranteed capacity allocated to the mobile network. The dimensioning of theguaranteed capacity should follow the mobile network dimensioning.

Synchronization : An IEEE1588 master is located on the controller site. TheLTE BTS on each site is synchronized via IEEE1588. The LTE BTSsynchronizes the co-located GSM BTS via RP3-01.

Network redundancy : It is assumed that the transport network featuresinherent redundancy, transparently protecting the mobile traffic againstfailures inside the network.

Controller site redundancy: Controller site routers are doubled forredundancy. The BSC connections to the network are redundant, whereas foreach BTS the traffic is carried over a single link in the last mile. Theredundancy solution for the BSC is the usual, HSRP/VRRP based one.

Backhaul network bandwidth: The backhaul network supports bandwidthprovisioning for the BTSs. The provisioned bandwidth is assumed to bealways sufficient for the LTE traffic subject to TAC and for the controlledamount of GSM. The provisioning of bandwidth is transparent to the mobilenetwork and it is considered part of the network operation.

Backhaul network QoS: Within the backhaul network, all traffic is carried asone performance class. Edge Routers and BTSs are configured to prioritizetraffic based on the DSCP.

VLAN usage: VLANs are deployed in the backhaul network to separate theBTS broadcast domains and to facilitate mapping of traffic to Ethernetservices. At BTS, management plane is separated to its own VLAN. In thisconfiguration, VLANs are configured to the BSC and the site routers as well.

4.1 Recommended Network Configuration Description4.1.1 General configuration

In this recommended configuration, two or three Ethernet services per group of BTSsites are used, each Ethernet service providing the same performance class. OneEthernet service is used per GSM BTSs and the other is used for LTE. The traffic ofthe RATs is carried on separate Ethernet services to separate the GSM backhaul fromother traffic. The LTE BTS of BTS site 2 as well as of BTS site 3 uses the sameEthernet service to increase the possibilities for statistical multiplexing among thetraffic of these BTSs. GSM BTS use a dedicated Ethernet service each allowing toconfigure the Ethernet services for all GSM BTSs in the same way. For GSM BTS,




there would be no multiplexing gain by carrying the traffic of several BTSs on oneEthernet service. This configuration is shown in Figure 12: Two Ethernet services withsingle performance class.

APToP

master

BTS

site 3

LTEBTS

GSMBTS

BSC

BTS

site 2

LTEBTS

GSMBTS

BTSsite 1

GSMBTS

LTEBTS

AP

L2network

A/S1

Figure 12: Two Ethernet services with single performance class

Each Ethernet service provides a single performance class. This performance classmust be suited for the most stringent requirements from the different traffic types thatare the Ethernet services provide performance class High. As QoS unaware policersare used at the attachment points, no difference can be made between high- and low-priority traffic. Therefore all the capacity of the Ethernet service is provided asguaranteed bandwidth, the peak bandwidth is equal to guaranteed bandwidth.

According to Table 1: Average traffic per GSM BTS and Table 4: LTE traffic model,the traffic volumes for GSM and LTE are 4 Mbps and 72 Mbps respectively. As inChapter 3, the Ethernet service for GSM is configured with more bandwidth that is a

guaranteed bandwidth of 5 Mbps. 4 Mbps of the LTE traffic has to be considered ashigh-priority. For the Ethernet service of BTS site 1 a guaranteed bandwidth of 80Mbps is used, for the Ethernet service of BTS sites 2 and 3 a capacity of 100 Mbps isused, increasing the potential gain by statistical multiplexing. 100Mbps is based on themaximum of peak bandwidth of one BTS (72000 kbps) and the sum of averagebandwidth of both BTSs (2x41500 kbps) and rounded up to 100 Mbps.

For LTE, the amount of high-priority traffic is far below the available capacity of theEthernet services. LTE TAC is not needed and will not be used in this configuration.GSM Packet Abis congestion control will be used in the same way as in Chapter 3: GSM and WCDMA.

The MTU of the LTE BTS is configured to 1560 bytes. Note that Ethernet frames of upto 2000 bytes can be carried across the Ethernet service. This allows sending 1500byte end user packets across the LTE S1/X2 interfaces without causing IPfragmentation. The additional 60 bytes are needed for the GTP/UDP/IP overhead onthe S1 and X2 interface.

4.1.2 Feature usageThe most relevant features for deploying GSM and LTE over a shared backhaulnetwork in this recommended network configuration are listed below.

4.1.2.1 GSMThe GSM transport related features are listed as follows:




DN09123915Issue 03

BSS101459 Full GE support for FIYB/FIQB

BSS21445 Packet Abis Congestion Reaction

BSS21454 Packet Abis over Ethernet


Other features used in the reference configurations are listed below

BSS21520 RF Sharing GSM-LTE

4.1.2.2 LTEThe LTE transport related features are listed as follows:


LTE119 Gigabit Ethernet (GE) optical interface




LTE134 Timing over Packet



LTE649 QoS aware Ethernet switching

LTE931 Ethernet Jumbo Frames

Other features used in the reference configurations are listed as follows:

LTE447 SW support for RF sharing GSM-LTE

LTE746 IP based Filtering for BTS Site Support Equipment


The bandwidth on the Ethernet services for GSM is not shared with other traffic. Theamount of GSM traffic on each Ethernet service is controlled with Packet AbisCongestion Control. The uplink LTE traffic is shaped in each BTS to avoid bufferoverflows in the BTS integrated switch as well as to keep the traffic amount within theEthernet service bandwidths. This implies that the capacity of the LTE Ethernetservice for BTS sites 2 and 3 is shared statically in the uplink among the BTSs. Indownlink direction the bandwidth is shared dynamically by shaping the traffic of bothBTSs together in the edge routers.

The burst sizes of the Ethernet services are 0.5 Mbit for the GSM Ethernet services, 8Mbit for the LTE Ethernet service of the standalone site, and 11 Mbit for the LTEEthernet service of the BTS chain.

4.2.2 ShapingIn downlink direction, the traffic for each of the LTE Ethernet services is shaped in theedge routers to the Ethernet service bandwidth and burst size. The mapping ofDSCPs to queues is defined in Table 14: 1SP+5WFQ scheduler. The downlink GSM




traffic is controlled by Packet Abis congestion control, no shaping is needed in theedge routers.

In uplink direction, each GSM BTS shapes its own traffic in the same way as in theGSM+WCDMA configuration, see Chapter 3.2.2: Shaping.

The amount of LTE traffic with guaranteed bit rate is far less than the availablebandwidth. According to dimensioning 2 Mbps of traffic with QCI1 are expected,whereas at least 80Mbps are available for LTE traffic per BTS chain. Therefore trafficadmission control is not needed; the default values – 1000 Mbps – of the parameterstacLimitGbrNormal, tacLimitGbrHandover and tacLimitGbrEmergency are applied.

For the LTE BTSs, the traffic on the two VLANs is shaped to avoid packet drop at theattachment point. For the LTE BTSs on site 2 and 3, the bandwidth is split statically inthe uplink. The BTSs shape the traffic to a small burst size such that no large burstscan build up in uplink. Shaping takes layer 2 overheads into account.

Parametername

user, control,synchronization plane site1

user,control,synchronization planesite 2, 3

management plane

Comment

Yes Yes No

1560 1560 1522 prevent bursts

78000 49000 1000

Configured per BTS,shaping per VLAN

false(0) Ethernet overhead isconsidered.

Table 35: LTE BTS uplink shaping parameters

For BTS sites 2 and 3, three Ethernet services are defined. 2 VLANs are mapped toeach Ethernet service. Note that both LTE BTSs are connected to the same VLANs.Therefore, X2 traffic among the two LTE BTSs does not traverse the MBH network.

The guaranteed bandwidth at each attachment point for the LTE Ethernet service is100 Mbps. In downlink direction, the site routers have to shape the traffic of bothVLANs together to 100 Mbps. Downlink GSM traffic is controlled using Packet Abiscongestion control. In uplink direction, the GSM BTS shape their egress traffic perinterface, whereas the LTE BTSs shape the traffic per VLAN.




DN09123915Issue 03

APToP

master

BTSsite 3

LTEBTS

GSM

BTS

BSC

BTSsite 2

LTEBTS

GSM

BTS AP

L2network

LTE U/C/SLTE M

GSM U/CGSM M

1Mbps

Phys IF

E S 1 P C

H i g h

E S 3 P C

H i g h

E S 2 P C

H i g h

GSM U/CGSM M

ES1 PC High100Mbps

ES2 PC High5Mbps

ES3 PC High5Mbps

5Mbpsboth VLANs

5Mbpsboth VLANs

Phys IF5Mbps

both VLANs(PAbis CC)

5Mbpsboth VLANs(PAbis CC)

VLAN

VLAN

1Mbps

49Mbps49Mbps100Mbps

both VLANs

Figure 13: Shaping for GSM + LTE configuration

4.2.3 VLAN Filtering According to Table 25: VLAN ID in Chapter 2.10: Traffic Aggregation on BTS site, theVLAN IDs as shown in Figure 14: VLAN IDs used in GSM+LTE configuration are usedfor BTS sites 2 and 3.

APToP

master

BTSsite 3

LTEBTS

GSMBTS

BTSsite 2

LTEBTS

GSMBTS

AP

L2network

LTE U/C/S 3502LTE M 3002

GSM U/C 1003GSM M 503

GSM U/C 1002GSM M 502

35023002

1003503

1002502

1003503

35023002

1003503

1002502

1003503

35023002

Figure 14: VLAN IDs used in GSM+LTE configuration

VLAN filtering is applied on the ports used for co-location and chaining. On the portused for backhaul, each VLAN used by the hub or the leaf BTS itself is used again.Therefore, there is no gain in using VLAN filtering on this port.

The parameters in the LTE BTSs are configured as shown in Table 36: VLAN filteringin GSM+LTE configuration.

Parameter Backhaul port Co-locationport

Chainport

site 1, 2, 3VLAN_ID VLAN_ID

site 1, 2, 3n/a true(1) true(1)

site 1n/a 501, 1001 n/a




Parameter Backhaul port Co-locationport

Chainport

site 2n/a 502, 1002 503, 1003,

3002,3502

site 3n/a 503, 1003 n/a

Table 36: VLAN filtering in GSM+LTE configuration

Untagged frames are discarded on the ports where VLAN filtering is applied.

4.2.4 SynchronizationIn this configuration, RF sharing among GSM and LTE system modules is used. Thishas an impact on synchronization among the two BTSs on each site. With RF sharing,the LTE BTS has to be clock master; GSM BTS has to be clock slave. The RP3interface is used for synchronization.

The synchronization is summarized in Figure 15: GSM and LTE synchronization.

ToPmaster

BTSsite 3

LTEBTS

GSMBTS

BSC

BTSsite 2

LTEBTS

GSMBTS

BTSsite 1

GSMBTS

LTEBTS

L2network

IEEE1588RP3 RP3

RP3

Figure 15: GSM and LTE synchronization

Note that a reset of the LTE BTS will cause loss of synchronization for the GSM BTS,which will cause a traffic interruption on the GSM BTS.

4.2.5 BTS site 1 (standalone site)BTS site 1 is not part of a BTS chain. The LTE BTS is used to provide the hubfunctionality.




The QoS aware BTS integrated switch is not used in the GSM BTS, therefore ingressrate limiting is not applicable.

To protect the LTE BTS against the injection of too much traffic via the connectionbetween BTS sites 2 and 3, the ingress rate at this interface is limited to 60 Mbps.This is exactly the sum of dimensioned capacity 7. By limiting the traffic from BTS site3, there will always be some capacity left for the LTE BTS on site 2, allowing tomanage this BTS even in case of an attack. The BTSs on the leaf site generatealmost no bursts; therefore there is no problem with the burst size of the ingress ratelimiter. The parameter l2IngressRate of this interface is set to RT_60. It is assumedhere that it is not possible to inject traffic between the co-located GSM BTS and theLTE BTS nor in downlink between the attachment point and the LTE BTS, thereforeingress rate limiting would not provide a benefit and is not used on these interfaces.The parameter l2IngressRate is set to RT_LINE_RATE.

4.2.7 BTS site 3 (leaf site)BTS site 3 is a leaf site. The LTE BTS is used to provide the hub functionality.

AP

BTSsite 3

LTEBTS

GSMBTS

BTSsite 2

FTLB

FIQB

Figure 18: GSM+LTE BTS site 3 (leaf site)

Following the configuration of BTS site 2, see Chapter 4.2.6: BTS site 2 (hub site), theLTE BTS is connected via 1000Base-T to the hub BTS site as well as to the co-located GSM BTS.

The BTS integrated switch is not used in the GSM BTS, therefore ingress rate limitingis not applicable.

Ingress rate limiting is not used in the LTE BTS, because larger bursts (8.5 Mbit) arepossible in downlink than can be tolerated by the ingress rate limiter of the BTSintegrated switch (8 Mbit).

4.2.8 BTS IP configurationThe basic principles as described in Chapter 2.9.1: VLAN usage at BTS site, apply inthis configuration as well. Note that the LTE BTSs on BTS site 2 and BTS site 3 areconnected to the same VLANs, nevertheless /29 subnets provide a sufficient amountof IP addresses for the BTSs as well as the edge routers.

7 To avoid changes of this parameter in case of future capacity upgrades one couldalso use a larger value such as limiting the rate to 100 Mbit. This value must besmaller than the capacity of the Ethernet service for LTE.




DN09123915Issue 03

The Green Energy Controller is connected to the LTE BTS on each site as describedin Chapter 2.9.3: IP address for SSE.

4.2.9 Controller siteThe edge routers separate the BSC site solutions from the needs of the shared mobilebackhaul network.

There are no specific requirements for the BSC site solution. Recommended BSC sitesolutions are described in BSC TRANSPORT SITE SOLUTION, RG20 MotherDocument, Scenarios and Requirements and BSC TRANSPORT SITE SOLUTIONRG20 Daughter Document External L2/L3 Equipment .

The shaping of downlink traffic is described in Chapter 4.2.2: Shaping, the routing andHSRP configuration is shown in Chapter 2.9.2.2: Routing configuration withHSRP/VRRP.




DN09123915Issue 03

Ethernet service has a single performance class. It has to be performance class Highso that also the LTE voice service can be carried over this Ethernet service.

Additionally, the capacity of the Ethernet service has to be provided completely asguaranteed bandwidth that is equals peak bandwidth.

To keep the configurations similar for WCDMA and LTE, a single Ethernet service withperformance class High is used also for WCDMA. The potential gain of using anEthernet service with performance class Low for HSPA NRT traffic would be small;this traffic is less than half of the overall traffic volume.

The BTSs of one RAT in a chain use the same Ethernet service to reduce thebandwidth requirements for the Ethernet service.

RNC

AP ToPmaster

BTSsite 3

WCDMABTS

LTEBTS

BTSsite 2

WCDMABTS

LTEBTS

BTSsite 1

LTEBTS

WCDMABTS

AP

L2network

S1/Iu

Figure 19: Several Ethernet services with single performance class

The bandwidth of the Ethernet services is provided completely as guaranteedbandwidth. For the chain of BTS sites 2 and 3, the bandwidth is dimensionedcorresponding to the maximum of peak bandwidth of one BTS and the sum of averagebandwidth of both BTSs. The average number for LTE non-GBR user plane is derivedfrom user demand on the air interface.


LTE GBR user plane (VoIP, QCI1) n/a 2000

LTE non-GBR user plane 38000 68000

LTE control plane 200 1000

LTE management plane 64 1000

IEEE1588 16 16

WCDMA control plane 507 507

WCDMA user plane RT + DCH NRT 3701 3701

WCDMA CCH 66 66

WCDMA user plane HSPA NRT 4418 41200

WCDMA management plane 64 2000

Table 37: LTE and WCDMA traffic amount




The average amount of traffic of one LTE BTS is 41500 kbps; the peak amount is72000 kbps. For the chain of LTE BTSs on sites 2 and 3 the Ethernet service has toprovide at least 83000 kbps of guaranteed bandwidth, for BTS site 1 a guaranteedbandwidth of 72000 kbps is sufficient.

For a WCDMA BTS, there is 8772kbps average amount of traffic and 47490kbps peakamount of traffic. Both for the standalone BTS on site 1 as well as for the chain of BTSon sites 2 and 3, the Ethernet services have to provide a bandwidth of 47490 kbps.

The guaranteed bandwidth values are rounded up to provide some headroom forfuture traffic growth, see Table 38: WCDMA+LTE information rates.

Ethernetservice

Site RAT Performanceclass

guaranteed bandwidthequal to peak bandwidth

[Mbps]

ES1 1 WCDMA High 50

ES2 1 LTE High 80

ES3 2+3 WCDMA High 50

ES4 2+3 LTE High 100

Table 38: WCDMA+LTE information rates

5.1.2 Feature usageThe most relevant features for deploying WCDMA and LTE over a shared backhaulnetwork in this recommended network configuration are listed below.

5.1.2.1 WCDMA RAN992 HSUPA Congestion Control

RAN1110 HSDPA Congestion Control RAN1254 Timing over Packet for BTS Application SW




RAN1769 QoS aware Ethernet switching


RAN2071 Synchronous Ethernet Generation

RAN2440 Fast IP Rerouting

5.1.2.2 LTEThe LTE transport related features are listed below








DN09123915Issue 03



LTE592 Link Supervision with BFD

LTE713 Synchronous Ethernet

LTE866 Fast IP Rerouting


The bandwidth of an Ethernet service is shared only among BTSs of the same radiotechnology. Different approaches are used in downlink and uplink to share thebandwidth. In uplink, the bandwidth is shared statically among the BTSs and eachBTS shapes the traffic per VLAN to the corresponding limit. In downlink direction thebandwidth is shared dynamically; the edge routers shape the aggregated traffic forboth BTSs to the capacity of the corresponding Ethernet service.

The WCDMA downlink traffic is limited by the edge routers. There is no gain in usingthe internal flow control of the RNC in addition. Therefore IFC is switched off.

The complete bandwidth of the Ethernet services is provided as guaranteedbandwidth. Even for the Ethernet service used by two BTSs, there is more bandwidthavailable than needed for the GBR bearers of both BTSs. Therefore, CAC and TACare not used for WCDMA and LTE, respectively. Also, the gain for the WCDMAEthernet service of using RAN1886 Efficient Transport for small IP packets would berelatively small; therefore this feature is not used in this configuration.

In uplink direction the BTSs are configured to not generate bursty traffic such thatproblems with Ethernet switches with small buffers are avoided. In the downlinkdirection, the supported burst sizes of the Ethernet services are utilized. The BTSintegrated switch have to cope with large bursts, but as all interfaces used provide thesame line rate it is possible to forward the data as quickly as it arrives. Some smallamount of buffering might be needed due to the X2 traffic among the LTE BTSs in thechain. This traffic has to be aggregated with the downlink traffic for the LTE BTS onthe leaf BTS, due to the small amount of X2 and as the BTSs do not send burstytraffic themselves this aggregation does not cause problems.

The traffic is aggregated by the integrated switching functionality of the WCDMA BTS.This does not support switching of Ethernet frames larger than 1522 bytes, thereforethe support for jumbo frames for LTE cannot be used and IP fragmentation on the S1and X2 interfaces might occur.

5.2.2 ShapingUplink shaping is performed in the BTSs; the bandwidth is split statically among theBTS in a chain and among the different VLANs, see Table 39: Uplink shaping forWCDMA and LTE configuration.

Parameter BTS site 1 BTS site 2 BTS site 3 Comment

WCDMAuser, control,synchronization plane

48Mbps 23 Mbps 23 Mbps

1522 bytes 1522 bytes 1522 bytes preventbursts




DN09123915Issue 03

AP

BTSsite2

LTEBTS

WCDMABTS

APL2

network

LTE U/C/S 3502LTE M 3002

WCDMA U/C/S 2002WCDMA M 1502

Router1

Router2

RNC

ToPmaster

S1/Iu

BTSsite3

LTEBTS

WCDMABTS

15022002

35023002

35023002

35023002

35023002

35023002

15022002

15022002

Figure 21: VLAN IDs used in WCDMA+LTE configuration

VLAN filtering is applied on the ports used for co-location and chaining. On the portused for backhaul, each VLAN used by the hub or the leaf BTS itself is used again.Therefore there is no gain in using VLAN filtering on this port.

The parameters in the WCDMA BTSs are configured as shown in Table 40: VLANfiltering in WCDMA+LTE configuration.

Parameter Backhaul port port to co-locatedLTE BTS

Chain port

,site 1, 2, 3

ADMIT_TAGGED (1)

ADMIT_TAGGED(1)

ADMIT_TAGGED (1)

, site 1 2-4094 3001, 3501 n/a

, site 2 2-4094 3002, 3502 1502, 2002,3002, 3502

, site 3 2-4094 3002, 3502 n/a

Table 40: VLAN filtering in WCDMA+LTE configuration

Untagged frames are discarded on the ports. On the ports towards the backhaulnetwork, all VLAN IDs are allowed to ease configuration. The parameters

and are not relevant as they applyto untagged frames; nevertheless, the parameter is configuredto its default value of 1 and considered in the VLAN ID list for the backhaul port.

In the LTE BTS the BTS, integrated Ethernet switch is not used, therefore no VLANfiltering is used either.

5.2.4 SynchronizationWhere possible, the WCDMA hub BTS synchronizes the LTE leaf BTS withsynchronous Ethernet. A hub BTS with an FTIB transport module cannot regenerateSyncE; in this case an additional E1 line is used. An overview for the different sites isshown in Figure 22: Synchronization overview for WCDMA and LTE co-location.




RNC

AP ToPmaster

BTSsite 3

WCDMABTS

(FTIB)

LTEBTS

BTSsite 2

WCDMABTS

(FTLB)

LTEBTS

BTSsite 1

LTEBTS

WCDMABTS

(FTIB)

APL2

network

SyncE IEEE1588E1

E1

Figure 22: Synchronization overview for WCDMA and LTE co-location

5.2.5 BTS site 1 (standalone site)This BTS site is not part of a BTS chain. A WCDMA BTS with an FTIB transportmodule provides the hub functionality.

AP

BTSsite 1

WCDMABTS

LTEBTS

FTLB

FTIB

Figure 23: WCDMA + LTE BTS site 1 (standalone site)

1000Base-T is used among the BTS, whereas the WCDMA BTS is connected with1000Base-X to the backhaul.

The WCDMA BTS acts as an IEEE1588 slave and synchronizes an additional E1 line,

see Table 41: WCMA BTS as IEE1588 slave and Master on E1. The FTIB transportmodule cannot generate Synchronous Ethernet.


true(1) Belongs to the BTSSCWmanaged object

false(0)

Top(4) IEEE1588




DN09123915Issue 03


1 Not relevant withIEEE1588

(1)

true(1) Not relevant withIEEE1588

Not relevant withIEEE1588

5 seconds Not relevant withIEEE1588

1

Table 41: WCDMA BTS as IEEE1588 slave and Master on E1

The LTE BTS is synchronized via an additional E1 line.

The WCDMA and the LTE BTS shape their own egress traffic to the values defined inTable 39: Uplink shaping for WCDMA and LTE configuration. The BTS integratedswitch in the WCDMA BTS is used for traffic prioritization only see Chapter 2.10: Traffic Aggregation on BTS site.

Ingress rate limiting is not used in the WCDMA BTS, because larger bursts (13 Mbit)are possible in downlink than can be tolerated by the ingress rate limiter of the BTSintegrated switch (560 kbit).

The BTS integrated switch is not used in the LTE BTS, therefore ingress rate limitingis not applicable.

5.2.6 BTS site 2 (hub site)BTS site 2 is a hub site that relays traffic between the network and another BTS site.One of the BTSs at this site aggregates the traffic both from the leaf BTS site as wellas from a co-located BTS; therefore an additional hop for the traffic of the leaf BTSsite is avoided. The WCDMA BTSs are used to provide the hub functionality, on thisspecific site the FTLB transport module is used as it provides the necessary amount ofEthernet interfaces.

AP

BTSsite 2

WCDMABTS

LTEBTSFTLB

FTLB

BTSsite 3

Figure 24: WCDMA + LTE BTS site 2 (hub site)




It is assumed that the WCDMA BTS is connected via optical 1000Base-X to theattachment point, a 1000Base-T connection is assumed to connect to the leaf BTSsite. The 2 nd electrical interface is also 1000Base-T and is used to connect to the LTEBTS.

The WCDMA BTS acts as an IEEE1588 slave, regenerating SyncE towards the co-located LTE BTS. Actually, SyncE is also regenerated on the interface towards thechaining BTS and on the backhaul interface, even if it is not used there. IEEE1588 isselected as the only synchronization source.

Synchronous Ethernet regeneration is switched on, SSM messages of type ITU areused and sent as untagged Ethernet frames, see Table 42: WCDMA BTS asIEEE1588 slave and SyncE master.


true(1) This BTSsynchronizesthe LTE BTS

true(1) SSM as a slowprotocol shouldbe untagged

(default)

IEEE1588

1 Not relevantwith IEEE1588

1

Not relevantwith IEEE1588

true(1) Not relevantwith IEEE1588

5seconds Not relevantwith IEEE1588

1

Table 42: WCDMA BTS as IEEE1588 slave and SyncE master

The LTE BTS is synchronized via Synchronous Ethernet.

The WCDMA and the LTE BTS shape their own egress traffic to the values defined inTable 39: Uplink shaping for WCDMA and LTE configuration. The BTS integratedswitch in the WCDMA BTS is used for traffic prioritization only see Chapter 2.10.

There can be up to 75 Mbps of uplink traffic from BTS site 3. This amount of traffic islarger than the backhaul capacity of the WCDMA BTS on site 2 acting as hub, whichis 50 Mbps. Therefore it is not possible to limit the ingress traffic from site 3 such thatsome transport capacity remains for managing this BTS on site 2. Therefore ingressrate limiting is not used in the WCDMA BTS on site 2 and the parameter

is set to




DN09123915Issue 03

The BTS integrated switch is not used in the LTE BTS, therefore ingress rate limitingis not applicable.

5.2.7 BTS site 3 (leaf site)BTS site 3 is a leaf site. A WCDMA BTS with an FTIB transport module provides thehub functionality.

AP

BTSsite 3

WCDMABTS

LTEBTS

BTSsite 2

FTIB

FTLB

Figure 25: WCDMA + LTE BTS site 3 (leaf site)

Following the configuration of BTS site 2, see Chapter 5.2.6: BTS site 2 (hub site), theWCDMA BTS is connected via 1000Base-T to the hub BTS site; it uses the otherelectrical 1000Base-T interface to connect to the co-located LTE BTS.

Synchronization, uplink shaping, and ingress rate limiting are configured similarly tothe standalone BTS site, see Chapter 5.2.5: BTS site 1 (standalone site).

5.2.8 BTS IP configurationBFD triggered static routes are used in the BTS to connect them to both edge routers,see Chapter 2.9.2.1: Routing configuration with BFD-triggered static routes. Note thatthe WCDMA BTSs on BTS site 2 and BTS site 3 are connected to the same VLANs,nevertheless /29 subnets provide sufficiently many IP addresses for the BTSs as wellas the edge routers. Similarly, the LTE BTSs are connected to the same VLANs.

The Green Energy Controller is connected to the WCDMA BTS on each site asdescribed in Chapter 2.9.3: IP address for SSE.

5.2.9 Controller siteThe edge routers separate the RNC site solution from the needs of the shared mobilebackhaul network.

There are no specific requirements for the RNC site solution. Recommended RNC sitesolutions are described in Configuring WCDMA and Flexi Direct Transport andRAN1884: Cisco 76xx as RNC Site Router, in Nokia Siemens Networks WCDMARAN.

The shaping of downlink traffic is described in Chapter 5.2.2: Shaping, the routingconfiguration is shown in Chapter 3.2.1: General.




References

GSM

1. Flexi Multiradio BTS GSM/EDGE System Module (ESMB/C) Description,

DN09468832. BSS101417: QoS Aware Ethernet Switching DN0988144

3. BSS21454: Packet Abis over Ethernet, BSS21439: Packet Abis Sync. ToPIEEE1588v2, BSS30450: Packet Abis Synchronous Ethernet, and BSS21444:Packet Abis Security, DN0963184

4. BSC TRANSPORT SITE SOLUTION, RG20 Mother Document, Scenarios andRequirements, DN0976611

5. BSC TRANSPORT SITE SOLUTION RG20 Daughter Document External L2/L3Equipment, DN0976623

6. BSC EDGE Dimensioning, RG20, DN7032469

7. Transport Network Solutions for BSS, RG20, DN7079267WCDMA

8. Configuring WCDMA and Flexi Direct Transport, RU30, DN70118388

9. Dimensioning WCDMA RAN document, in Nokia Siemens Networks WCDMARAN, Rel. RU30, System Library

10. RAN1884: Cisco 76xx as RNC Site Router, in Nokia Siemens Networks WCDMARAN, System Library

11. Impact of Transport Network Impairments on WCDMA Network Performance,DN0983316, Rel. RU20, System Library

LTE

12. Configuring LTE RL20 RAN Transport, RL 30, DN0984506

13. Configuring LTE Transport, RL30, DN0984506

14. LTE Traffic Model, RL30, DN0951784

15. LTE Access Dimensioning Guideline, RL 30, DN0951772

Multiradio

16. Backhaul Sharing QoS Guideline, DN09123927

17. IP Transport Monitoring with Standalone Devices, DN09117727

General

18. NSN Green Energy Controller




DN09123915Issue 03

Glossary

Acronym Explanation

AP Attachment Point

ARP Allocation and Retention Priority

BBU Battery Backup Unit

BCSU BSC Signaling Unit

BSC Base Station Controller

BTS Base Transceiver Station

CAC Call Admission Control

CC Congestion Control

CESoPSN Circuit Emulation Service over Packet Switched Network

CS Circuit Switched

DL Downlink

DSCP Differentiated Services Code Point

ES Ethernet Service

ETP-E Exchange Terminal for Packet Abis over Ethernet

GBw Guaranteed Bandwidth

GE Gigabit Ethernet

GPRS General Packet Radio Service

GSM Global System for Mobile Communications

HLR Home Location Registry

HSPA High-Speed Packet Access

HSDPA High-Speed Packet Downlink Access

HSUPA High-Speed Packet Uplink Access

HSRP Hot Standby Routing Protocol

IFC Internal Flow ControlLAN Local Area Network

LCT Local Craft Terminal

LMP Local Management Port

LTE Long Term Evolution

MBH Mobile Backhaul



Recommended Configurations for Multiradio SharedTransport

Acronym Explanation

MPLS Multiprotocol Label Switching

MTU Maximum Transmission Unit

NE Network Element

NRT Non real-time

OMS Operation and Maintenance Server

PBw Peak bandwidth

PC Performance Class

PCP Priority Code Point

PS Packet Switched

QoS Quality of Service

RAB Radio Access Bearer

RAN Radio Access Network

RAT Radio Access Technology

RNC Radio Network controller

RT Real-time

RTSL Radio Timeslot

SP Strict Priority

SPI Scheduling Priority IndicatorSSE Site Support Equipment

SyncE Synchronous Ethernet

TAC Transport Admission Control

THP Traffic Handling Priority

ToP Timing over Packet

TRX Transmitter/receiver

TWAMP Two-way active measurement protocol

UL UplinkVLAN Virtual LAN

VRRP Virtual Router Redundancy Protocol

WCDMA Wideband Code Division Multiple Access

WFQ Weighted Fair Queuing



6 Other notesThe NOTICE icon is used to indicate risk of property damage. In addition, there areicons for general notes and tips.

NOTICE: Hazard descriptionSecond paragraph

General note or hintSecond paragraph

TipSecond paragraph

Alert symbols andsignal word

Level definition

DANGER! Will result in death or serious (irreversible) personal injury

WARNING! Could result in death or serious (irreversible) personal injury

CAUTION! May result in minor or moderate (reversible) personal injury

NOTICE: Property damage or malfunction. No personal injury is possible.

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