1-Tn_ss005_e1_1 Zxwn Msc Server Dimensioning(New Edit)-73
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Transcript of 1-Tn_ss005_e1_1 Zxwn Msc Server Dimensioning(New Edit)-73
ZXWN MSC Server Dimensioning
Course Objectives
Basic Concept A Interface Iu Interface Mc Interface Nc Interface
Description of Traffic Model
During network planning, the first step is to confirm the traffic model. The traffic model varies with operator, and the planning results from different traffic models are very different.
The traffic model is actually statistics data, so the adopted traffic model during planning is made according to the statistics data of the previous period. However, subscriber actions continuously changes, so the traffic model also continuously changes.
Description of Traffic Model
The traffic model usually includes the following parts:
MS-related part: It usually includes the following parameters
Traffic model parameters Reference Values Remarks
Number of calls in busy hours 1.59 Related with subscriber actions, this parameter greatly varies with operator, and with area of the same operator.
Number of video calls for a 3G subscriber in busy hours 0.12 Related with subscriber actions, this parameter is only for
3G subscribers, and greatly varies with operator.
Number of SMSs in busy hours 0.8 Related with subscriber actions, this parameter greatly varies with operator.
Number of LUs in busy hours 2 Related with the network radio planning, this parameter is of little difference between operators.
Number of HOs in busy hours 1 Related with the network radio planning, this parameter is of little difference between operators.
Number of Auths in busy hours 2 Related with the network parameter setting, this parameter is of little difference between operators.
Cross-VLR location update ratio 0.2 Related with the network radio planning, this parameter is
of little difference between operators.
CAMEL subscriber ratio 0.25 This parameter is related with the service development of operators
CRBT subscriber ratio 0.3 This parameter is related with the service development of operators
Mean call duation 60S Related with subscriber actions, this parameter greatly varies with operator.
Mean call duration of video calls fro 3G subscribers 90S Related with subscriber actions, this parameter greatly
varies with operator.
Description of Traffic Model
Description of Traffic Model
Trunk-related part
Traffic model parameters
Reference Values
Remarks
Erl 0.6It is usually 0.7 or 0.8, having no difference between operators.
Mean call duration 60SRelated with subscriber actions, this parameter greatly varies with operator.
Description of Traffic Model
Traffic model parameters Reference Values Remarks
Intra MSC Traffic 0.4 ZTE ASSUMPTION
Inter MSC Transit Traffic 0.15 ZTE ASSUMPTION
MS<->PSTN 0.3 ZTE ASSUMPTION
MS<->Other PLMN 0.3 ZTE ASSUMPTION
CRBT Holding Time (S) 15 ZTE ASSUMPTION
Networking Planning Procedure
Networking Planning Procedure Network planning has two cases. In one case, a new network is built. In the other case, one or more Network Elements
(NEs) are added to an existing network.
Networking Planning Procedure
Networking planning procedure mainly contains the following steps: Plan the network capacity and subscriber distribution,
including the subscriber capacity of each local network. Plan the networking scheme of the network, including
NE distribution and design. Plan the networking scheme of the bearer network, and
the bearer type to be adopted. Plan the networking scheme of the service network. Plan the networking scheme of the operation and
maintenance network (billing, network management and other systems).
Plan the networking scheme of the equipment.
Course Objectives
Basic Concept A Interface Iu Interface Mc Interface Nc Interface
A Interface
MSCSBSC
VLAN/MACIP
SCTPM3UASCCP
BSSAP
A Interface
Lu FlowNo. Message Name Message Direction Packet Length
(SCCP Layer)
1 CR(InitUE(LU Req)) BSC → MSC 61
2 CC MSC → BSC 9
3 DT1(DT(LU Accept)) MSC → BSC 17
4 DT1(DT(TMSI ReAlloc Compete))
BSC → MSC 12
5 DT1(DT(Clear Command)) MSC → BSC 13
6 DT1(DT(Clear Complete)) BSC → MSC 10
7 RLSD MSC → BSC 9
8 RLC BSC → MSC 7
Total number of BSC → MSC packets
4 90
Total number of MSC → BSC packets
4 48
MONo. Message Name Message
Direction
Packet Length (SCCP Layer)
1 CR(InitUE(CM service request)) BSC → MSC 55
2 CC MSC → BSC 9
3 DT1(DT(CM service accept)) MSC → BSC 12
4 DT1(DT(Setup)) BSC → MSC 29
5 DT1(DT(Call proceeding)) MSC → BSC 12
6 DT1(DT(Assignment Request)) MSC → BSC 28
7 DT1(DT(Assignment Complete)) BSC → MSC 13
8 DT1(DT(Alerting)) MSC → BSC 16
9 DT1(DT(Connect)) MSC → BSC 20
10 DT1(DT(Connect acknowledge)) BSC → MSC 12
11 DT1(DT(Disconnect)) MSC → BSC 15
12 DT1(DT(Release)) BSC → MSC 12
13 DT1(DT(Release complete)) MSC → BSC 12
14 DT1(DT(Clear Command)) MSC → BSC 13
15 DT1(DT(Clear Complete )) BSC → MSC 10
16 RLSD MSC → BSC 9
17 RLC BSC → MSC 7
Total number of BSC → MSC packets 7 138
Total number of MSC → BSC packets 10 146
MT
No. Message Name Message Direction
Packet Length (SCCP Layer)
1 UDT(Page) MSC → BSC 49
2 CR(InitUE(Page response)) BSC → MSC 54
3 CC MSC → BSC 9
4 DT1(DT(Setup)) MSC → BSC 31
5 DT1(DT(Call confirm)) BSC → MSC 12
6 DT1(DT(Assignment Request)) MSC → BSC 33
7 DT1(DT(Assignment Complete)) BSC → MSC 13
8 DT1(DT(Alerting)) BSC → MSC 12
9 DT1(DT(Connect)) BSC → MSC 12
10 DT1(DT(Connect acknowledge)) MSC → BSC 12
11 DT1(DT(Release)) MSC → BSC 12
12 DT1(DT(Release complete)) BSC → MSC 12
13 DT1(DT(Clear Command)) MSC → BSC 13
14 DT1(DT(Clear Complete )) BSC → MSC 10
15 RLSD MSC → BSC 9
16 RLC BSC → MSC 7
Total number of BSC → MSC packets 9 181
Total number of MSC → BSC packets 7 119
Authentication
No. Message Name Message Direction Packet Length
(SCCP Layer)
1 DT1(DT(AUTH REQ)) MSC → BSC 29
2 DT1(DT(AUTH RESP)) BSC → MSC 16
3 DT1(DT(SECURITY CMD)) MSC → BSC 21
4 DT1(DT(SECURITY CMP )) BSC → MSC 10
Total number of BSC → MSC packets
2 26
Total number of MSC → BSC packets
2 50
SMS MO
No. Message Name Message Direction Packet Length (SCCP Layer)
1 CR(InitUE(CM service request)) BSC → MSC 55
2 CC MSC → BSC 9
3 DT1(DT(CM service accept)) MSC → BSC 12
4 DT1(DT(CP-DATA)) BSC → MSC 153
5 DT1(DT(CP-ACK)) MSC → BSC 12
6 DT1(DT(CP-DATA)) MSC → BSC 15
7 DT1(DT(CP-ACK))) BSC → MSC 12
8 DT1(DT(Clear Command)) MSC → BSC 13
9 DT1(DT(Clear Complete )) BSC → MSC 10
10 RLSD MSC → BSC 9
11 RLC BSC → MSC 7
Total number of BSC → MSC packets 5 237
Total number of MSC → BSC packets 6 70
SMS MTNo. Message Name
Message Direction
Packet Length (SCCP Layer)
1 UDT(Page) MSC → BSC 49
2 CR(InitUE(Page response)) BSC → MSC 54
3 CC MSC → BSC 9
4 DT1(DT(CP-DATA)) MSC → BSC 152
5 DT1(DT(CP-ACK)) BSC → MSC 12
6 DT1(DT(CP-DATA)) BSC → MSC 15
7 DT1(DT(CP-ACK)) MSC → BSC 12
8 DT1(DT(Clear Command)) MSC → BSC 13
9 DT1(DT(Clear Complete )) BSC → MSC 10
10 RLSD MSC → BSC 9
11 RLC BSC → MSC 7
Total number of BSC → MSC
packets 5 98
Total number of MSC → BSC
packets 6 244
Hand Over Outgoing
No. Message NameMessage Direction
Packet Length (SCCP Layer)
1 DT1(DT(Handover Required)) BSC → MSC 32
2 DT1(DT(Handover Command)) MSC → BSC 23
3 DT1(DT(Clear Command)) MSC → BSC 13
4 DT1(DT(Clear Complete )) BSC → MSC 10
5 RLSD MSC → BSC 9
6 RLC BSC → MSC 7
Total number of BSC → MSC
packets 3 49
Total number of MSC → BSC
packets 3 45
Hand Over Incoming
No. Message NameMessage Direction
Packet Length (SCCP Layer)
1 DT1(DT(HandoverRequest))MSC →
BSC72
2DT1(DT(HandoverRequestAcknowled
ge))BSC →
MSC16
3 DT1(DT(Handover Detect))BSC →
MSC13
4 DT1(DT(Handove Complete)) BSC → MSC
13
Total number of BSC → MSC packets 3 42
Total number of MSC → BSC packets 1 72
A Interface
Summary: BSC - MGW signaling traffic
Service Flow
Message Direction Number of Packets Packet Length (SCCP Layer)
LUBSC - MGW 4 90
MGW - BSC 4 48
CALLBSC - MGW 8 159.5
MGW - BSC 8.5 132.5
SMSBSC - MGW 5 167.5
MGW - BSC 6 157
HOBSC - MGW 3 45.5
MGW - BSC 2 58.5
AUTHBSC - MGW 2 26
MGW - BSC 2 50
A Interface
Signaling Traffic Dimensioning---MSCS –BSC BWms-a-bsc-mgw =( Ncall × BWcall-bsc-mscs +
Nlu × BWlu-bsc-mscs + Nsms × BWsms-bsc-mscs + Nauth × BWauth-bsc-mscs + Nho × BWho-bsc-mscs ) × 8 / 3600 (bps)
BWx = Message length + Number of messages × Protocol header overhead
BWa-bsc-mscs = Nuser ×BWms-a-bsc-mscs
A Interface
Traffic Model
Since the BSCMSC signaling traffic in most of the flows is heavy, only the BSCMSC signaling traffic is calculated.
Traffic model parameters Values
Ncall 1.69
Nlu 2
Nsms 0.8
Nauth 2
Nho 1
Nuser 1400000*0.6 (stage1)
Protocol Header Overhead
ProtocolsHeader Overhead
( BYTE) Remarks
MAC8 + 14 + 4 + 8 =34
8 bytes are for the lead code, 14 bytes are for the header overhead, 4 bytes are for the tail overhead, and 8 bytes are for the interval between framesA
MAC/VLAN8 + 18 + 4 + 8 =38
VLAN header is added
IP 20
SCTP 28
M3UA 40 Adding all the optional items
Bearer Type Possible Combination Header Overhead
IP M3UA/SCTP/IP/VLAN/MAC 126
A Interface
A Interface
For Example BWcall-bsc-mscs =159.5+8*126 = 1167.5 BWlu-bsc-mscs =90+4*126=594 BWsms-bsc-mscs =167.5+5*126=797.5 BWauth-bsc-mscs =26+2*126=278 BWho-bsc-mscs =45.5+3*126=423.5 BWms-a-bsc-mscs = ( 1.69 × 1167.5 + 2 × 594 +
0.8× 797.5 + 2 × 278 + 1× 423.5 ) × 8 / 3600 =10.62bps
BWa-bsc-mscs =840000*10.62=8.92Mbps
Course Objectives
Basic Concept A Interface Iu Interface Mc Interface Nc Interface
Iu Interface
RNC
VLAN/MACIP
SCTPM3UASCCP
RANAP
MSCS
No. Message NameMessage Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1 CR ( InitUE ( LU Req)) RNC - > MSCS
99 3
2 CCMSCS - >
RNC8 1
3 DT1 ( DT ( LU Accept)) MSCS - > RNC
45 2
4DT1 ( DT ( TMSI ReAlloc Compete))
RNC - > MSCS
21 1
5 DT1 ( DT ( IuReleaseCmd)) MSCS - > RNC
19 1
6 DT1 ( DT ( IuReleaseComplete)) RNC - > MSCS
14 1
7 RLSDMSCS - >
RNC8 1
8 RLCRNC - >
MSCS7 1
Total number of RNC → MSC packets 4 141 6
Total number of MSC →RNC packets 4 80 5
Iu Interface—LU
Iu Interface—MO call
No. Message NameMessage Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1 CR ( InitUE ( CM service request))
RNC - > MSCS
91 3
2 CC MSCS - > RNC
8 1
3 DT1 ( DT ( CM service accept)) MSCS - > RNC
19 1
4 DT1 ( DT ( Setup)) RNC - > MSCS
39 2
5 DT1 ( DT ( Call proceeding)) MSCS - > RNC
34 2
6 DT1 ( RAB ASSIGNMENT REQUEST)
MSCS - > RNC
175 5
7 DT1 ( RAB ASSIGNMENT RESPONSE)
RNC - > MSCS
27 2
8 DT1 ( DT ( Alerting)) MSCS - > RNC
21 1
9 DT1 ( DT ( Connect)) MSCS - > RNC
21 1
No. Message NameMessage
Direction Packet Length (SCCP Layer)
AAL5 bandwidth(number)
10 DT1 ( DT ( Connect acknowledge)) RNC - > MSCS 26 2
11 DT1 ( DT ( Disconnect)) MSCS - > RNC 24 1
12 DT1 ( DT ( Release)) MSCS - > RNC 26 2
13 DT1 ( DT ( Release complete)) RNC - > MSCS 21 1
14 DT1 ( DT ( IU RELEASE COMMAND))
MSCS - > RNC 19 1
15 DT1 ( DT ( IU RELEASE COMPLETE))
RNC - > MSCS 14 1
16 RLSD MSCS - > RNC 8 1
17 RLC RNC - > MSCS 7 1
Total number of RNC → MSC packets 7 225 12
Total number of MSC →RNC packets 10 355 16
Iu Interface
No. Message Name Message Direction Packet Length (SCCP Layer)
AAL5 (number)
1 UDT ( Page) MSCS - > RNC 67 2
2 CR ( InitUE ( Page response)) RNC - > MSCS 91 3
3 CC MSCS - > RNC 8 1
4 DT1 ( DT ( Setup)) MSCS - > RNC 51 2
5 DT1 ( DT ( Call confirm)) RNC - > MSCS 30 2
6 DT1 ( RAB ASSIGNMENT REQUEST) MSCS - > RNC 175 5
7 DT1 ( RAB ASSIGNMENT RESPONSE) RNC - > MSCS 27 2
8 DT1 ( DT ( Alerting)) RNC - > MSCS 21 1
9 DT1 ( DT ( Connect)) RNC - > MSCS 40 2
10 DT1 ( DT ( Connect acknowledge)) MSCS - > RNC 21 1
11 DT1 ( DT ( Release)) MSCS - > RNC 26 2
12 DT1 ( DT ( Release complete)) RNC - > MSCS 21 1
13 DT1 ( DT ( IU RELEASE COMMAND))
MSCS - > RNC 19 1
14 DT1 ( DT ( IU RELEASE COMPLETE))
RNC - > MSCS 14 1
15 RLSD MSCS - > RNC 8 1
16 RLC RNC - > MSCS 7 1
Total number of RNC → MSC packets 8 251 13
Total number of MSC →RNC packets 8 375 15
Iu Interface--MT
No. Message Name Message Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1 CR ( InitUE ( CM service request)) RNC - > MSCS 92 3
2 CC MSCS - > RNC 8 1
3 DT1 ( DT ( CM service accept)) MSCS - > RNC 39 2
4 DT1 ( DT ( CP-DATA)) RNC - > MSCS 153 4
5 DT1 ( DT ( CP-ACK)) MSCS - > RNC 26 2
6 DT1 ( DT ( IuReleaseCmd)) MSCS - > RNC 19 1
7 DT1 ( DT ( IuReleaseComplete)) RNC - > MSCS 14 1
8 RLSD MSCS - > RNC 8 1
9 RLC RNC - > MSCS 7 1
Total number of RNC → MSC packets 4 266 9
Total number of MSC →RNC packets 5 100 7
Iu Interface—SMS originating
Iu Interface—SM terminate
No. Message NameMessage
Direction Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1 UDT ( Page) MSCS - > RNC
64 2
2 CR ( InitUE ( Page response)) RNC - > MSCS
64 2
3 CCMSCS - > RNC
8 1
4 DT1 ( DT ( CP-DATA)) MSCS - > RNC
152 4
5 DT1 ( DT ( CP-ACK)) RNC - > MSCS
26 2
6DT1 ( DT ( IU RELEASE COMMAND))
MSCS - > RNC
19 1
7DT1 ( DT ( IU RELEASE COMPLETE))
RNC - > MSCS
14 1
8 RLSDMSCS - > RNC
8 1
9 RLCRNC - > MSCS
7 1
Total number of RNC → MSC packets 4 111 6
Total number of MSC →RNC packets 5 251 9
Iu Interface--AUTH
No. Message NameMessage Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1DT1 ( DT ( AUTH REQ))
MSCS - > RNC
61 2
2DT1 ( DT ( AUTH RESP))
RNC - > MSCS
31 2
3DT1 ( DT ( SECURITY CMD))
MSCS - > RNC
65 2
4DT1 ( DT ( SECURITY CMP))
RNC - > MSCS
24 1
Total number of RNC → MSC packets
2 55 3
Total number of MSC →RNC packets
2 126 4
Iu Interface--Relocation
No. Message Name Message Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1 DT1 ( DT ( RelocationRequire))
RNC - > MSCS
262 7
2 DT1 ( DT ( RelocationCommand))
MSCS - > RNC
213 6
3 DT1 ( DT ( IU RELEASE COMMAND))
MSCS - > RNC
19 1
4 DT1 ( DT ( IU RELEASE COMPLETE))
RNC - > MSCS
14 1
5 RLSD MSCS - > RNC
8 1
6 RLC RNC - > MSCS
7 1
Total number of RNC → MSC packets
3 283 9
Total number of MSC →RNC packets
3 240 8
Iu Interface
No. Message NameMessage Direction
Packet Length (SCCP Layer)
AAL5 bandwidth(number)
1DT1 ( DT ( RelocationRequest))
MSCS - > RNC
262 7
2DT1 ( DT ( RelocationRequestAck)
RNC - > MSCS
226 6
3DT1 ( DT ( RelocationDetect)
RNC - > MSCS
14 1
4DT1 ( DT ( RelocationComplete)
RNC - > MSCS
14 1
Total number of RNC → MSC packets
3 254 8
Total number of MSC →RNC packets
1 262 7
Iu Interface
Summary:RNC - MSCS signaling bandwidth
Service Flow Message Direction Number of
Packets Packet Length
LURNCMGW 4 141
MGWRNC 4 80
CALLRNCMGW 7.5 238
MGWRNC 9 365
SMSRNCMGW 4 188.5
MGWRNC 5 175.5
HORNCMGW 3 537
MGWRNC 2 502
AUTHRNCMGW 2 55
MGWRNC 2 126
Iu Interface
Signaling Traffic Dimensioning---MSCS –RNC BWms-iu-rnc-mscs =( Ncall × BWcall-rnc-mscs +
Nlu × BWlu-rnc-mscs + Nsms × BWsms-rnc-mscs + Nauth × BWauth-rnc-mscs + Nho × BWho-rnc-mscs ) × 8 / 3600 (bps)
BWx = Message length + Number of messages × Protocol header overhead
BWiu-rnc-mscs = Nuser ×BWms-iu-rnc-mscs
Traffic Model Values
Ncall 1.69
Nlu 2
Nsms 0.8
Nauth 2
Nho 1
Nuser 1400000*0.4 (stage1)
Traffic Model
Iu Interface
Since the MSCSRNC signaling traffic in most of the flows is heavy, only theMSCSRNC signaling traffic is calculated.
Iu Interface
Protocol Header Overhead
ProtocolsHeader Overhead
( BYTE) Remarks
MAC8 + 14 + 4 + 8 =34
8 bytes are for the lead code, 14 bytes are for the header overhead, 4 bytes are for the tail overhead, and 8 bytes are for the interval between framesA
MAC/VLAN8 + 18 + 4 + 8 =38
VLAN header is added
IP 20
SCTP 28
M3UA 40 Adding all the optional items
Bearer Type Possible Combination Header Overhead
IP M3UA/SCTP/IP/VLAN/MAC 126
Iu Interface
For Example BWcall-rnc-mscs =365+9*126 = 1499 BWlu-rnc-mscs =80+4*126=584 BWsms-rnc-mscs =175.5+5*126=805.5 BWauth-rnc-mscs =126+2*126=378 BWho-rnc-mscs =502+4*126=1006 BWms-a-rnc-mscs = ( 1.69 × 1499 + 2 × 584 +
0.8 × 805.5 + 2 × 378 + 1× 1006 ) × 8 / 3600 =13.57bps
BWa-rnc-mscs =560000*13.57=7.6Mbps
Course Objectives
Basic Concept A Interface Iu Interface Mc Interface Nc Interface
Mc Interface
MGW
MSCS
VLAN/MACIP
SCTPM3UA
H.248/ISUP
Terminal Role Message Direction Message Length Number
Iu interface MO
MSCS->MGW 724 4MGW->MSCS 746 4
Iu interface MT
MSCS->MGW 973 6MGW->MSCS 912 6
Iu interface Handoff
MSCS->MGW 970 5
MGW->MSCS 831 5
IP originating side
MSCS->MGW 1243 7MGW->MSCS 1214 7
IP terminating side
MSCS->MGW 942 5MGW->MSCS 903 5
A interface MO
MSCS->MGW 404 3MGW->MSCS 322 3
A interface MT
MSCS->MGW 702 5MGW->MSCS 538 5
A interface Handoff
MSCS->MGW 664 4MGW->MSCS 772 4
Ai interface MSCS->MGW 272 2MGW->MSCS 216 2
Playingannouncement
MSCS->MGW 303 2MGW->MSCS 243 2
Mc Interface
1. Analyzing Header Overhead of Protocol Stacks
Protocol Stack Type Protocol Stack Type Remarks
H.248/M3UA/SCTP/IP/VLAN/MAC 126
H.248/SCTP/IP/VLAN/MAC 86
H.248/M3UA/SCTP/IP/MPLS/PPP 102
H.248/SCTP/IP/MPLS/PPP 62
Mc Interface
2. Calculation Method BWmc = Na-term × BWa-term + Niu-term × BWiu-
term + Nnb-ai-tdm-term × BWnb-ai-tdm-term + Nnb-ip-term × BWnb-ip-term
Since the MSCS MGW traffic is most of the flows is greater than the MGW MSCS, only the MSCS MGW traffic is calculated.
Mc Interface
Na-term: Number of terminals at the A interface Niu-term: Number of terminals at the IU interface Nnb-ip-term: Number of RTP channels when the Nb
interface adopts IP Nnb-ai-tdm-term: Number of channels when the Nb
interface adopts TDM + Number of TDM channels of the Ai interface
Mc Interface
BWmc: Total traffic over the Mc interface BWa-term: Taffic of each A interface over the Mc interface BWiu-term: Traffic of each Iu interface over the Mc interface BWnb-ip-term: Traffic of IP terminals of each Nb interface
over the Mc interface BWnb-ai-tdm-term: Traffic of TDM terminals of each Nb
interface over the Mc interface (as same as the traffic of TDM terminals of the Ai interface over the Mc interface)
Mc Interface BWa-term =( Etrunk × 3600 / Dcall ) × (( BWcall-a-
term + Nmess-call×Lpro) + Pho × ( BWho-a-term +Nmess-ho×Lpro) + Pcall-fail × ( BWann + Nmess-ann×Lpro)×8 / 3600 (bps)
BWiu-term =( Etrunk × 3600 / Dcall ) × (( BWcall-iu-term + Nmess-call×Lpro) + Pho × ( BWho-iu-term +Nmess-ho×Lpro) + Pcall-fail × ( BWann + Nmess-ann×Lpro)×8 / 3600 (bps)
BWnb-ip-term =( Etrunk × 3600 / Dcall ) × ( BWcall-nb-ip-term + Nmess-call×Lpro)×8 / 3600 (bps)
BWnb-ai-tdm-term =( Etrunk × 3600 / Dcall ) × ( BWcall-nb-ip-term + Nmess-call×Lpro)×8 / 3600 (bps)
Mc Interface Etrunk: Trunk circuit Erl Dcall: Mean call duration Nmess-call: Number of call flow messages Nmess-ho: Number of handoff flow messages Nmess-ann: Number of messages during the flow of
playing recorded announcement Lpro: Header overhead for transferring protocols Pho: Handoff ratio Pcall-fail: Call failure ratio BWcall-a-term: Mean length of the A interface terminal
messages in each call flow BWcall-iu-term: Mean length of the Iu interface terminal
messages in each call flow
Mc Interface
BWho-a-term: Mean length of the A interface terminal messages in each handoff flow
BWho-iu-term: Mean length of the Iu interface terminal messages in each handoff flow
BWcall-nb-ip-term: Mean length of the Nb interface IP terminal messages in each call flow
BWcall-nb-tdm-term: Mean length of the Nb interface TDM terminal messages in each call flow
Bwann: Mean length of messages in each flow of playing recorded announcement
Pho=Times of handoffs/calls in busy hours Pcall-fail=1 – Call completion ratio
Mc Interface
3.Suppose the traffic model is as follows.
Traffic Model Parameters Supposed Values
Each interface Erl 0 . 6
Mean call duration 60S
Handoff probability 0 . 4
Call failure ratio 0 . 4
Mc Interface
Required bandwidths of each terminal are as follows.
Terminal Type
Protocol Stack
BWa-term
BWiu-term
Nnb-ip-term
Nnb-ai-tdm-term
H.248/M3UA/SCTP/IP/VLAN/MAC 175 bps 239 bps 173 bps 50 bps
H.248/SCTP/IP/VLAN/MAC 139 bps 189 bps 150 bps 42 bps
H.248/M3UA/SCTP/IP/MPLS/PPP 149 bps 201 bps 159 bps 44 bps
H.248/SCTP/IP/MPLS/PPP 125 bps 172 bps 137 bps 37 bps
Mc Interface
A: Suppose there are 15000 A interface channels, and 500 Nb TDM interface E1s in the system, adopting the H.248/M3UA/SCTP/IP/VLAN/MAC protocol stacks. The traffic over the Mc interface is as follows.
Total traffic over Mc interface = 15000×163 + 500×30×50 =3195000bps = 3.195Mbps
3.2 Mbps traffic is reserved in engineering.
Mc Interface
B: Suppose there are 15000 Iu interface channels, and 15000 Nb IP interface RTP channels in the system, adopting the H.248/M3UA/SCTP/IP/VLAN/MAC protocol stacks. The traffic over the Mc interface is as follows.
Total traffic over the Mc interface = 15000×218 + 15000×173 =5865000bps = 5.865Mbps
6 Mbps traffic is reserved in engineering.
In CSL case,the BW of H.248
AErl =0.4 , IuErl =0.6, AiErl=0.6, NbErl=0.3
For a single MGW Erlang=40250
As a result, total H.248 message in Mc interface is:
(AErl* BWA-Term + IuErl * BW-Iu-term+ AiErl* BW-Ai-TDM-term+ NbErl* BW-Nb-ip-term)/0.6=40250*(0.4*175+0.6*239+0.6*50+0.3*173)/0.6=19.8 Mbps
Mc interface (ISUP over IP)
Each ISUP bidirectional calling has 354 Bytes For a single MGW Erlang=40250 Number of inter-offic BHCA=Number of CIC to
PSTN&PLMN*Possible Call Attempts on a CIC Number of CIC to PSTN&PLMN=Traffic to PSTN&PLMN/
Average Trunk Load=40250*60%/0.6=40250 Possible Call Attempts on a CIC= Average Trunk
Load/(60/3600)=0.6*3600/60=36 The total possible call attempts on Ai interface is:
40250*0.6/0.6*(0.6*3600/60)* 354*8/3600=1.14 Mbps
Total signaling message between MGW and MSC Sever includes H.248 massage, and ISUP message.
The total message flow between MGW and MSC Sever is:
(MessageH.248 +MessageISUP)= 19.8 Mbps+1.14 Mbps=20.94 Mbps
Course Objectives
Basic Concept A Interface Iu Interface Mc Interface Nc Interface
Nc Interface
1. Nc Protocol Stack
MSCS1
VLAN/MACI PSCTP
BI CC
MSCS2
MPLS/ PPP
M3UA
Nc Interface
1.TrFO- dalay forward bearer mode.
No. Message Name Direction Length (BICC Layer)
1 IAM Forward 68
2 APM Backward 41
3 APM Forward 184
4 APM Backward 184
5 COT Forward 7
6 ACM Backward 8
7 ANM Backward 21
8 REL Forwardor Backward 12
9 RLC The reverse of the REL 6
The number of messages 9
The Length of messages 531
Nc Interface 3. The lengths of signaling flow with different
protocol stacks
4. traffic model
Protocol Stack Signaling Flow Length
(Single Direction)
BICC/M3UA/SCTP/IP/VLAN/MAC 833
BICC/M3UA/SCTP/IP/MPLS/POS 725
BICC/SCTP/IP/VLAN/MAC 653
BICC/SCTP/IP/MPLS/POS 545
Traffic Model Parameters Parameter Value
Etrunk 0.6
Dcall 60s
Nc Interface
2.Calculation Formula BWnc = Ncic×BWcic (bps) BWnc: Required bandwidth of the Nc interface BWcic: Required bandwidth of each CIC trunk Ncic: Number of the CIC trunks BWcic = (Ecic × 3600 / Dcall)×BWcall×8/3600 (bps) Ecic: CIC trunk Erl Dcall: Mean call duration BWcall: Required bandwidth of each call
Ncic(inter office IP trunk)=total Erlang* Inter MSC ratio/Average Trunk Load=40250*0.15/0.6=10062.5
BWcic = (Ecic × 3600 / Dcall)×BWcall×8/3600 (bps)
=(0.6 × 3600 /60) ×833×8/3600
=66.64 bps
So : BWnc = Ncic×BWcic (bps)
= 10062.5×66.64=670565 bps=671Kbps