Ip over wdm

A study of “IP Over WDM”

Partha Goswami

22/07/05

2

Topics• Motivations for IP over WDM

• IP Traffic Over WDM

• MPLS approch for IP over WDM

• GMPLS Control Plane

• Optical Internetworking and Signaling across Network Boundary

3

Motivation for IP over WDM

Worldwide Network Demand

0

5000

10000

15000

20000

25000

30000

1996 1997 1998 1999 2000 2001 2002

Year

Gb

/s Data

Voice

Reference 14: Acute need to increase the data bandwidth

Reference 16: Exponential Growth of Internet

•The volume of the Data traffic exceeds the Voice traffic.

•Long Haul Optical network follows SONET/SDH transmission standardwith time fame of 125 μ sec.

• Most of the data traffics are due to IP traffic where existing transmission technique in the Fiber backbone is not giving Optimal Multiplexing.

• Several alternative are in Consideration:•IP over Fiber• PPP to replace SONET•Lightweight SONET

4

.

Inflexibility in bandwidth granularity

• Each traffic source must use a fixed multiple of OC1 (51.84 Mbps) rate, for example, OC-3 (155Mbps), OC-12 (622Mbps), OC-48 (2.4Gbps), and OC-192 (9.9Gbps).

High overhead

• SONET frame require a minimum of 3% overhead for framing, status monitoring, and management.

• Other Protocol overhead, HereIP Over PPP over SDH

PBX

SDH-DWDM

OLT

PBXOLT

Access ring

Metro ring

Regional ring

National Ring

ADM

How present network look like.

Motivation for IP over WDM Continued..

5

Motivation for IP over WDM Continued…• Advent of wavelength division multiplexing (WDM) technology that allows multiple

wavelengths on a single fiber, the "IP over fiber" issue takes on a new dimension.

• End stations (traffic sources) and routers (traffic switches) have a choice of wavelengths on which to direct their traffic.

• High capacity of WDM and exponential growth of IP traffic is the perfect match of the need and technology

Reference 15, Ch 1, Page 2Introduction of high capacity WDM

Reference 15, Ch 2, Page 14Thousand fold capacity enhancement for Submarine cable system

6

Challenges of IP over WDM

• IP over WDM domain, attempts to address issues like:• Light path selection and network routing • Support for various classes of service • Algorithms for network restorations and protection scheme• Integration with existing technology• Standardization of Signaling and protocol

• The future optical component technology may allow full optical switching of IP packets.

• The Optical switching can be classified as follows:• Optical Circuit switching (OCS)• Optical Burst Switching (OBS)• Optical Packet Switching (OPS)

7

Three Generation of Digital Transport Network

• First Generation: T1 , E1

• Second Generation : SONET , SDH

• Third Generation : Optical Transport network• Suitable for: Voice, Video, Data, QOS, BOD• Multiplexing and Switching scheme: WDM/O/O/O• Capacity: Tbps• Payload: Fixed or Variable length• Protocol support: PPP, IP, ATM, MPLS• Commercial Availability: Full feature 3rd Generation yet to arrive due to lack of mass scale commercial deployment O/O/O

Reference: 1, Page 1-4

8

IP Traffic Over WDM network• IP Traffic Over WDM is the Correct Choice

for Next Generation Internet backbone.

• OCS technology is matured.

• Network node will use Wavelength Routing Switch and IP router.

• Nodes are connected by fiber to form physical topology

• Any two IP router will be connected by all- Optical WDM Channel called light path

• The set of lightpath termed as Virtual topology.

• Multihop approach

Wave length Routed Network

λ1,λ2, λ3,λ4

λ1,λ2, λ3,λ4

λ1,λ2, λ3,λ4

λ1,λ2, λ3,λ4

λ1,λ2, λ3,λ4

λ1 λ1,λ2, λ3,λ4

λ2

λ3

λ4

WRS

Reconfigurable Wavelength Routing nodeReference 17

9

IP/WDM network Model

• IP Routers are Network element of IP Layer

• WXC, WADM are Network element of WDM Layer

• Overlay model: IP layer and optical layer are managed and controlled independently

• IP-NCM, WDM-NCM, UNI

• Integrated IP/WDM: Functionality of both IP and WDM are integrated at each node.

WRS

WDM NCM

IP NCM

IP NCM

Over Lay Model

WRS+ control

Integrated ModelReference 18:Ch 9, Page 347-351

10

Optical Packet switching• Large gap between IP route

processing and the capacity of WDM because of

• Electrically Store and forwarding technique

• One possibility is packet switching in optical domain instead of electrical domain

• Statistical Multiplexing• Hardware cost• Premature state

• Other Possible solutions in electrical domain are

– Fast lookup

– Parallelism of the forwarding

– Label switching Technique

HeaderSync Header Guard Payload

SyncPayload

Guard

• Format of an optical Packet• Header encoded at lower speed• Payload duration is fixed• Payload Variable bit rate up to 10 Gb/s• Header and payload at the same wavelength• Guard time to take care of delay variation• Sync bit used for packet synch

HeaderDelineation

HeaderupdatingHeader

Recovery

PayloadPosition

Switch Control Unit

PayloadDelineation

O/E O/E

FDL Synchronizer SwitchingFabric

Signal Regenerator

Demux Mux

A Generic Optical Packet switching node structure

Reference 18:Ch 9, Page 365-366Reference 19,20

11

Optical Burst Switching

λ0Control Channel

Data Channel 1

Data Channel 2

λ1

λ2

Fiber 1

Fiber 2

λ0 λ1 λ2

λ0 λ1 λ2

Core Router

Edge Router Access Network

Access Network

Access Network

OpticalSwitchingNetwork

FDL

FDL

FDL

FDL

Control Burst

Processing

RoutingTable

BufferAnd

Scheduler

IM

IM

OM

OMλ0

λ0

λ1

λ1

λ2

λ2 λ2

λ1

λ1

λ2

λ0

λ0

λ0 λ1 λ2

λ0 λ1 λ2

Demux

Mux

Optical Burst Switching node Architecture

• It Combines the advantages of OCS and OPS

• No buffering and Electronic Processing

• High bandwidth utilization

• Burst is aggregating a no of IP datagram destined for same egress router in the ingress router

• Control burst and Data Burst

• Node Architecture

Reference 18:Ch 9, Page 351-355Reference 21

12

MPLS approach in WDM network

• MPLS is the backbone for IP network.

• MPLS approach for OCS is Known as LOCS or MPλS

• MPLS approach is suitable for OBS and OPS using LOBS and LOPS respectively

• If Label of the MPLS is mapped with λ of the WDM network, then IP-MPLS frame work enables direct integration of IP and WDM

IP Over MPLS Over WDM

Reference 22,23

WRS

IP network

IP network

MPLS Network

MPLS Back bone for IP network

13

MPLS and Optical Network

• MPLS is the key components for 3rd generation Transport networks.

• MPLS Architecture is defined in RFC 3031 .

• Operations of Label switch router (LSR), Label assignments, and Label swapping.

• What is label switching and how it is different than traditional internets ?

• Correlations between MPLS label value and optical wavelength

Reference 1, Chapter 9

http://www.faqs.org/rfcs/rfc3031.html


14

Advantage of Label Switching

• Speed, delay and jitter: Faster than traditional IP forwarding

• Scalability: Large no IP address can be associated with few labels

• Resource consumption: Less resource for control mechanism to establish Label switch Path (LSP)

• Route control: More efficient route control than destination based routing

• Traffic Engineering: Allows network provider to engineer the link and nodes in the network to support different kind of traffic considering different constraints.

• Labels and Lambdas: Wave length can be used for Label and optical router capable of O/O/O can forward the traffic with out any processing delay

Reference 1, Ch 9

15

The forwarding Equivalence Class (FEC)

• What is FEC?– It associates an FEC value with destination address and

a class of traffic.– The class of traffic is associated with a destination

TCP/UDP port no and/or protocol ID field in the IP datagram header.

• Advantages of FEC– Grouping of packet into classes– For different FEC we can set different priorities– Can be used for efficient QOS operation

Reference 1, Ch 9, page 151

16

Types of MPLS nodes

• Ingress LSR: – User Traffic classifies into FEC. – It generate MPLS header and

assign it an initial label.– If QOS is implemented then LSR

will condition the traffic

• Transit LSR– Uses the MPLS header for

forwarding decision– It also performs label swapping– Not concerned with IP header

• Egress LSR– It removes MPLS header

Transit LSR

Ingress LSR

Egress LSR

The MPLS nodes


18

Label swapping and Traffic forwarding

• LSR forwarding table map the Incoming Label and interface to an Outgoing Label and interface.

• An LSR may explicitly request a Label binding for an FEC from the next hop.

• Ingress LSR analyzes the FEC field and correlate the FEC with a Label, encapsulate the datagram.

• The Transit LSR process only label header based on the LSR forwarding table.

Source network

Destination Network

IP

Reque

st

Reques t

RequestLa

bel

1L

abel

2

IPL1

IPL3

IPL

2

Label

3

Label allocation and MPLS forwarding

Reference 1, Ch 9, Page 154 and Reference 2, Ch 5, Page 151

IP

19

MPLS Support of Virtual Private Network• MPLS can be used to support VPN customers

with very simple arrangement.

• It is possible by label stacking : Placing of more than one Label in the MPLS header.

• This concept allows certain Label to be processed by the node while others are ignored.

• VPN backbone can accommodate all traffic with one set of Labels for the LSP in the back bone.

• The customers Labels are pushed down and are not examined in the through the MPLS tunnel.

• When the packet arrive at the end of the VPN backbone LSP then the LSR pops the Labels.

• Assumptions:

– Customers at the same ends of the MPLS end to end path.

– Customers have the same QOS requirements and FEC parameters

Customer 1

Customer 3

Customer 2

Customer 3

Cust 2

Customer 1

IP 31 IP 31

IP 32 IP 32

IP 33IP 33

IP 31

IP 32

IP 33

LSR A LSR BLSR C

34

34

34

IP 31

IP 32

IP 33

35

35

35

VPN

Label Stacking in VPN


20

MPLS Traffic Engineering• It deals with Performance of network.

• High performance required for Customer’s QOS need.

• Methodologies are Measurement of Traffic and Control of Traffic.

• RFC 2702 specify the requirement of TE over MPLS.

• Objective of TE are Traffic Oriented and Resource Oriented performance enhancement.

• Traffic oriented performance objective are minimizing Traffic loss, minimizing delay, maximizing throughput and enforcement of SLAs.

• Resource oriented performance objective deals with Communication Links, Routers and Servers.

• Efficient management of the available bandwidth is the essence of TE

Reference 1, Ch 9, page 156-157


22

Multi Protocol Lambda switching (MPλS)• MPλS is the framework for inter working

Optical networks and MPLS.

• MPLS and Optical network both have control plane to Manage the user traffic.

• MPLS Control Plane deals with Label distribution and binding an end to end LSP

• Optical Control Plane deals with setting up wavelength, optical coding scheme (SDH/SONET), transfer rates, Protection switching options.

• Reference 3 and 4 discussed about adapting the MPLS TE Control Plane for optical Cross Connect.

MPLS Control Plane

Optical Control Plane

LSPCross Connect table

OSPCross Connect Table

Label Mgt

λ Mgt

The MPLS and Optical Control Plane

MPLS network

WDM network

MPLS network over WDM network


23

Relationship of OXC and LSR operations

Label Switch Router

(LSR)

Optical Cross Connect

(OXC)

Data Transfer Label Swapping operation to transfer labeled packet from an Input port to an Output port

Connect optical Channel of one Input port to an Output port

Control Plane Discovery,distribute and maintain relevant state information related with MPLS.

Discovery,distribute and maintain relevant state information related with optical Transport network (OTN)

Forwarding information

Forwarding information Label is appended with Data Packet

Forwarding information is implied in the data Channel.

Storage of switching information

Input - output relation is maintained in Next hop label forwarding entry (NHLFE)

Input - output relation is maintained by Wavelength forwarding information base

USER

MPLS

Optical

USER

MPLS

Optical

Sending Node

Receiving Node

MPLS and Optical network Layered model


24

MPLS and MPλS Correlation

MPLS MPλS

Key aspect Label Value Optical Wavelength

Ingress Node Role of Ingress Node on the user Traffic, termed as Ingress LSR

MPLS Label is correlated with appropriate wavelength, termed as LSR/OXC

Core node Termed as Transit LSR Termed as Transit PXC, used to process the wavelength to make the routing decisions.

Path Termed as Label switch Path (LSP)

Termed as Optical switched path(OSP)

Transit PXC

Ingress LSR/OXC

Egress LSR/OXC

Map Label to Wavelength

Map wavelength to LabelUser

User

Processλ

Processing of user Traffic in the MPλS


25

MPLS and Optical TE similarities

• MPLS term Traffic trunk = Optical Layer Term Optical Channel trail

• Attributes of Traffic for MPLS TE:

– Traffic Parameters: Indicate BW requirement of traffic trunk

– Adaptive attributes: Sensitivity and Possibility of re-routing of trunk

– Priority attribute: Priority of path selection and path placement for trunk

– Preemption attribute: Whether a traffic trunk can preempt an existing trunk

– Resilience attribute: Survivability requirement of Traffic trunk

– Resource class affinity attribute: Restrict route selection to specific subset of resources


26

Possibilities for the MPλS Network

• Following work remain in Reference 4 which needs to be done to complete the MPλS Network:

• Concept of link bundling.

• Distribution of OTN topology , available bandwidth, available channels and other OTN topology state using extension of IS-IS or OSPF

• Exploring the possibilities of fiber termination in the same device which perform the role of OXC and IP router.

• Uniform Control Plane for LSR and PXC as close interaction are needed between Control and Data plane for the interwork of Label and wavelength.

• How to increase the utilization of the optical Channel trail in case traffic in the LSP mapped with Optical channel is low.


27

IP, MPLS and Optical Control Plane• 3rd Generation transport networks

encompasses three Control plane.

• All the above control plane need to be coordinated to take the benefit of the followings:

– Route discovery of IP control Plane• Routing protocol advertises and discover

address as well as routes

– Traffic Engineering capability of MPLS control plane

• MPLS Label distribution protocol will bind the IP address with Label

– Forwarding speed of optical data plane• MPLS Label will be mapped with

wavelength• Optical node can perform PXC –based

O/O/O operation• O/E/O based Label label swapping will not

be needed.• Ideally same wavelength can be used on

each OSP segment.


IP Control Plane (Routing Layer)

Data Plane(Forwarding)

MPLS Control Plane(Binding Layer)

Data Plane(Forwarding)

Optical Control Plane(λ Mapping Layer)

Data Plane(λ Mapping Layer)

Mapping of IP Address

to MPLS Label

Mapping of MPLS Labelto wavelength

User Payload IP HeaderLabel

Header

Inter working of three Control Plane

28

Optical Control Plane• The requirement of Optical Control Plane as

specified in Reference 5

• Permanent Optical channel setup by NMS by network management protocol

• Soft permanent optical channel by NMS using network generated signaling and routing protocol

• Switched Optical Channel which can be setup by customer on demand using signaling and Routing protocol

• The Optical Node consist of OXC and Optical network control plane

• Between two neighboring node there is pre configured control channel which may In band or Out of band.

• Switching function is done by OXC but it isbased on how cross connect table is configured

Reference 1, Ch 10, page 169 and Reference 6, Ch 14, page 427

OXC

Control

Optical Network Node

OXC

Control

Optical Network Node

Data

Control

Optical Node Model

31

Generalized MPLS use in optical network• Purpose of GMPLS development: (Reference 8)

• To support MPLS operation in optical network with ability to use the optical technologies as

» Time division ( SONET ADM)

» Wavelength

» Spatial switching( Incoming Fiber to out going fiber)

• GMPLS assume that forwarding decision based on time slot , wavelength and physical ports.

• GMPLS Terminology:1. Packet switch capable (PXC): Process traffic based on packet/cell/frame boundaries

2. Time division Multiplex capable (TDM): Process Traffic based on a TDM boundary, such as SONET/SDH node.

3. Lambda-switch capable (LSC): Process traffic based on the Optical wavelength

4. Fiber switch capable (FSC): Process traffic based on the physical interface.


32

• GMPLS = Extension of MPLS to support various switching technology (RFC 3945)

• Following switching technology is considered:• Packet switching: Forwarding capability packet based, IP Router

• Layer2 switching: Forwarding data on cell or frame: Ethernet, ATM

• TDM or Time slot switching: Forwarding data based on time slot: SONET,DCS, ADM

• Lambda switching: Performed by OXC

• Fiber switching: Performed by Fiber switch capable OXC

• GMPLS control plane focus on full range of switching technology

• Natural Hierarchy of Label stacking in GMPLS:

Packet LSP over Layer 2 LSP over over Time slot LSP over λ-switching LSP over Fiber switching LSP

Generalized MPLS use in optical network continued…

Reference 26, 27

Fiber LSP

λ- LSP

Time slot LSP

Layer 2 LSP

Packet LSP

GMPLS Label stacking LSP

33

GMPLS Control Plane• Optical network is

becoming the Transport network for IP traffic

(IP over Optical)

• IP centric optical control plane is the best choice

• GMPLS control plane for Optical network contains Routing, Signaling and Restoration Management


Routing protocol

Resource discovery and disseminationCSPF path computation

Wave length Assignment

SignalingRestoration Management

GMPLS Control Plane for Optical Network

34

Resource Discovery and Link-state Information Dissemination

• Each Optical node need to know the Global topology and resource information, which is possible by broadcasting local resource use and

neighbor connectivity information by each optical node.

• It can be done the OSPF (Reference 9) and its extension ( Reference 10)

• It can also be done by IS-IS (Reference 11) and its extension (Reference 12)

• Here neighbor discover require inband communication which is possible for

Opaque OXC with SONET termination.

• For Transparent OXC neighbor discovery generally utilizes a separate protocol such as Link management protocol ( Reference 13)

• Issues: Scalability problem for link addressing and Link state advertisement

• Solutions: • Unnumbered links: Globally unique end node ID ( LSR ID) plus local selector ID

• Link Bundling: The link attribute of multiple wavelength channel of similar characteristics can aggregated.


35

CSPF Path computation

• CSPF = SPF + resource constraint + policy constraint : To achieve the MPLS TE objective RFC 2702

• Such path computation is NP complete and Heurestic have to be used.

• The objective of path computation in optical network is to minimize the resource required for routing light paths for a given SLA.

• For optical network CSPF algorithm needs to be modified for the following reason

• Link Bundling and Restoration Path Computation

• The Solution is Shared Risk Link Group (SRLG): Administrative group associated with some optical Resources that probably share common vulnerability to a Single Failure.

• Example: Fiber in the same conduit can be assigned with one SRLG

36

Wavelength Assignment

• Wave length Continuity constrained for Transparent OXC

• Opaque OXC and wave length Conversion

• Wave Length Assignment Problem is constrained to the CSPF algorithm

• Wave length assignment • At the Source• Random wave length assignment• Dynamic wavelength

Reservation

Reference 6, Ch14, Page 430Reference 24,25

λ1λ2λ3

Fiber 1

λ1λ2λ3

λ1λ2λ3

λ1λ2λ3

Transparent OXC

Fiber 1

Fiber 2Fiber 2

λ1λ2λ3

λ4λ5λ6

λ1λ2λ3

λ4λ5λ6

Opaque OXC

Fiber 1Fiber 1

32

1

Light Path Demand set in a ring

37

Restoration Management• Difference between Optical Layer protection with IP layer MPLS Layer.

• Management and co-ordination among multiple layer is an important issue.

• Optical Protection mechanism can be classified as follows:

• Path Protection

• Link Protection

• Path Protection classified as follows:

• Disjoint Path Protection: 1+1 , 1:1 and M:N

• Link-dependent Path protection

• Restoration Management: Failure detection, Failure notification and Failure restoration.

• Detection by lower layer impairments, higher layer link probing.

• Time for restoration is due to restoration path computation and traffic rerouting from primary path to restoration path

Reference 6, Ch14, Page 431

38

Signaling• Signaling is distributed path establishment

operation across Optical network

• Major Operation of Light Path signaling are Light Path setup, Teardown and Abort

• Light Path Setup: SETUP, SETUP ACK, SETUP NAK

• Light Path commitment Phase: ABORT

• Light Path Teardown : TEARDOWN and TEARDOWN ACK

• Addressing Issue due to High no of entity in Optical network: Unique IP to OXC and other resources through Selector

• Each node will Maintain a Light Path table to record the Lightpath ID, Incoming/ Out going Port no, SRLG so on..

INT_A INT_BSRC

DST

SETUP

SETUP

SETUP

SETIP ACK

SETIP ACK

SETIP ACK

Tim

e

Reference 6, Ch14, Page 432-435

39

GMPLS Signaling Functional Requirements

• Same switching functionality for both end LSR

• GMPLS extends MPLS Signaling in many aspect

• Generalized label is defined with enough flexibility to represent Label for different switching type.

• Label suggestion capability by the upstream node will reduce the LSP setup delay.

• Label set: Upstream restrict the label selection of the down stream to acceptable limit.

• GMPLS support Bi-directional LSP setup.

• Explicit Label label selection offers capability of explicit label selection on a specific on an explicit route

• GMPLS data channel and control channel may be separate.

• GMPLS signaling for fault handling should minimize the packet loss.


42

IP – Centric Control PlaneReceive incoming messageProcess the request with the help of other moduleInitializing the control Plane

OpticalNetwork Main Module

Connection Module

Resource Management

Module(RMM)

Protection/Restoration

Module(PRM)(CM)

(MM)

•Light Path Signaling•Maintenance

•Routing and wavelength Assignment (RWA)•Topology and Resource Discovery•QOS support

•Survivability•Fault Monitoring•Fast Protection/

Restoration

UNI

IP Network

Reference 6, Ch14, Page 461-469Reference 28

43

Connection Module (CM)

OpticalNetwork

UNI

IP Network

Light Path IDSRC DEST SEQ

NODE NODE NUM

ID ID

Status(Creating/

Reserved/

Active/

Deleted)

QOS

Type

Input Output λ ID

Port Port

ID ID

•Connection Request Message Contents•Light Path ID•Light Path Type (Primary/ Protection)•Routing Path•Assigned wave Length•QOS type•SRLG list of Primary Path

•At each hop, request Message is processed•Destination node send ACK along the same path•If there is resource conflict NAK is sent back

44

Connection Module (CM) Continued……

Processing of Lightpath signaling

Resource Reservation/Release Lightpath State Transfer

Determination of Input/ Output port from the LT

If Assigned wavelength is availableSet the wavelength status

“ Used Preemptible”

QOS = best Effort

QOS = Mission CriticalIf Assigned Wavelength is available

Change the status to to “ Used and Non-perrmptible”

Else abort the existing lightpath on this wavelength. ThenChange the status to to “ Used and Non-perrmptible”

QOS= Protection Sensitive

If it is Primary Path and wavelength status “ available”change the status to “ Used Preemptible”

If it is Protection LightPath and wavelength status “ available”Set the status to” Reserved”

Else Check the SRLG list

NAK

Creating

Deleted Active

Reserved1

2

3

45

6

1. Protection Path: Reservation Ack2. Failure on Primary path3. Tear Down abort4. NAK5. Primary Path : Setup ACK6. Tear Down Abort

45

Resource Management Module

• Functionality: Resource Discovery, Maintenance, QOS support, RWA

• Neighbor discovery mechanism by sending Hello Message on all out going link.

• Local Connectivity Vector (LCV): Store the cost of the Adjacent Node.

• If LCV is updated , it is broadcasted to the network

• Local resource availability stored in Local Resource Table (LRT)

• “λi status” indicate state of ith wavelength in the fiber attached to the port

• Possible states are “used and preemptable” , “used and non-preemptable” , “Reserved”, “Available” and “ Faulty”

• “λi SRLG list” stores the SRLG information of the primary path whose protection path has reserved the wavelength (λi status = Reserved)

OpticalNetwork

UNI

IP Network

Port

no

Peering Node ID

λ1 status

λ1 SRLG list

λ2 status

λ2 SRLG list

…

Local Resource Table (LRT)

46

Resource Management Module Continued….

• Each node build its own Topology connectivity Matrix (TCM) with N nodes.

• Each row of TCM is the LCV of the node I plus a time stamp.

• RMM also maintain a Global Resource Table (GRT) consisting of LRT of all nodes.

• RMM utilize different RWA algorithm to support QOS.

• QOS support:• Best-effort service• Mission critical service• Protection Sensitive Matrix

OpticalNetwork

Node 1

Node 2

Node

3

Node

4

Node

5

Node

6

Node 1

Node 2

Node

3

Node

4

Node

5

Node

6

Topology Connectivity Matrix

47

Protection and Restoration Module

• Functions: Setup Co-ordination of Primary and protection Light Path, Fault detection,

and notification.

• Fault can be detected by as follows:• Low level impairments • Higher layer link probing

• Failure can happen for Control Plane or OXC.• Failure indication Signal (FIS) send to the

source node.

• If Qos requirement is Restoration the restoration Path will be calculated.

• If Qos requirement is Protection then source node will invoke the setup signal for the Lightpath previously reserved.

• For Mission critical destination node detect the failure of the primary Lightpath and turn to protection path.

OXC

Control

Optical Network Node A

OXC

Control

Optical Network Node B

Data

Control

(RMM) (PRM)(CM)

(MM)

(RMM) (PRM)(CM)

(MM)

Control Plane of Node A Control Plane of Node A

Connection RequestNAK/ACK

48

Optical Internetworking and Signaling across Network Boundary

• Need for Inter-domain Optical network

• Need for standard• Addressing scheme to identify light path

end points• Routing Protocol• Standard signaling protocol across

Network to Network interface• Restoration procedure• Policies that affect the flow of Control

Information

• Solution is by implementing:• External Signaling Protocol (ESP):

Used for Signaling across NNI• Internal Signaling protocol( ISP): May

be different for different network• Possibility of BGP extension is being studied for

Routing .

• Possibility of CR-LDP or RSVP-TE extension is being studied for Signaling across the network boundary.

NNI

NNI

49

Signaling across NNI

ISPISP ISP

ESP

ISP

ESP

ISP

ISP

ESP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ISP

ESP

ISP

ESP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP

ISP

ESP


50

Conclusion• Development and implementation of

GMPSL over the existing technology can only bring the reality of IP over WDM

• Performance of GMPLS in the hybrid scenario should be simulated.

51

References1. Optical Networks, Third Generation Transport Systems by Uyless Black

2. Optical Network Control Architecture, Protocols, and Standards by Greg Bernstein

3. Multiprotocol Lambda Switching:Combining MPLS Traffic Engineering Control with Optical Crossconnects by Daniel Awduche, Movaz NetworksYakov Rekhter, Juniper Networks , IEEE Communications Magazine • March 2001

4. Multi-Protocol Lambda Switching: Combining MPLS Traffic Engineering Control With Optical Crossconnects draft-awduche-mpls-te-optical-03.txt

5. Considerations on the development of an Optical Control Plane, Internet Draft Document: draft-freeland-octrl-cons-01.txt by IP-Optical Working Group

6. IP Over WDM: Building the next Generation Optical Internet, Edited by Sudhir Dixit

7. IP over Optical Networks: A Framework: draft-ietf-ipo-framework-00.txt by Bala Rajagopalan

8. Generalized MPLS - Signaling Functional Description: draft-ietf-mpls-generalized-signaling-05.txt by Network Working Group

9. OSPF Version 2: RFC 2328

52

Reference Continued….10. OSPF Extensions in Support of Generalized MPLS: draft-ietf-ccamp-ospf-gmpls-extensions-00.txt

11. Use of OSI ISIS for Routing in TCP/IP and Dual Environments: RFC 1195

12. IS-IS Extensions in Support of Generalized MPLS: draft-ietf-isis-gmpls-extensions-04.txt

13. Link Management Protocol (LMP) : draft-ietf-ccamp-lmp-10.txt

14. http://www.cs.columbia.edu/~hgs/internet/traffic.html

15. WDM Technologies, Volume III - Optical Networks - 2004 - (By A.K.Dutta)

16. http://bgp.potaroo.net/

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Reference Continued….

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Ip over wdm

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