1

Lesson 8 GMPLS (Generalized Multi-protocol Label Switching)

Objectives :GMPLS is a protocol that is applied to the TDM layer, the wavelength-path layer, and the fiber layer by generalizing the label concept of MPLS. GMPLS makes it possible to execute distributed control ― a feature of MPLS ― thereby simplifying the operation. It is also possible to totally engineer the traffic based on the traffic information or topology information of each layer and to improve the utilization efficiency of the network.

2Fig.8.1

Network layer structure

Packet layer

TDM layer

Fiber layer

TDM layer

Fiber layer

Packet layer

layer

Fiber layer

Packet layer

layer

(a) (b) (c)

20052000 2010

(a) (b) (c)

3Fig.8.3

IP packet

(a) Packet

Label

…

… …

(b) TDM

…

Time slot

Wavelength

(c) λ

Link

Link

Link

Link

(d) Fiber

…

Fiber

Concept of label

MPLS Shim header

Time Slot #

λ1 : Red

λ2 : Blue

Fiber #

4Fig.8.4

FSC-LSP

LSC-LSP TDM-LSP PSC-LSP

Hierarchization of LSP

LSP : Label Switching Path

5Fig.8.5

LSCTDMPSC FSC FSC

TDM region

PSC region

LSC region

FSC region

LSC TDM PSC

PSC: Packet Switching CapabilityTDM: Time Division MultiplexingLCS: Lambda Switching CapabilityFSC: Fiber Switching Capability

Relationship between the switching capability and the region

6Fig.8.6

Packet layer(Distributed control)

TDM layer(Distributed control)

λ-layer(Distributed control)

Fiber layer

Central controlling device

Central controlling device

Current IP/MPLS network

7Fig.8.7

Packet layer(Distributed control)

TDM layer(Distributed control)

Fiber layer

λ-layer(Central control)

GMPLS network of which each layer is used distributed control method

8Fig.8.8

Fiber layer

Packet layer+

TDM layer+

λ-layer

(Distributed control)

GMPLS network that is controlled distributtedly and integratedly with multiple layers

Integrated traffic engineering = Multi-layer TE

9Fig.8.9

Fiber layerλ-layerPacket layer

Multi-layer traffic engineering

10Fig.8.10

RSVP-TE extensionOSPF extension LMP

GMPLS architecture

Major protocols of GMPLS

OSPF-TE : Routing

RSVP-TE : Signaling

LMP : Link Management Protocol

11Fig.8.11(b) Physical link topology

A

B C

D

E

Packet layerTE link

A

B C

DE

TDM layer

TDM LSP

(a) TE link topology

Concept of TE (Traffic Engineering)

TE Link

A→E direct link for packet layer

12Fig.8.12

Opaque LSA format (RFC2370)

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS age | Options |Link-state type|+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Opaque Type | Instance |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Advertising Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS Sequence Number |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS checksum | Length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| |+ +| Opaque Information |+ +| ... |

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Sub-TVL Type | length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Value... |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

1

10 Advertisement within areaNumber attached to identify the multiple traffic engineering LSAs

Indicates traffic engineering LSA

1-9 (MPLS extension)11,14,15,16 (GMPLS extension)

Length of Sub-TLV

13Fig. 8.13

1 1 Link type2 4 Link ID3 4 Local interface IP address4 4 Remote interface IP address5 4 Traffic engineering metric6 4 Maximum bandwidth7 4 Maximum reservable bandwidth8 32 Unreserved bandwidth9 4 Administrative group11 8 Link Local/Remote Identifiers 14 4 Link Protection Type15 variable Interface Switching Capability Descriptor16 variable Shared Risk Link Group

Added for GMPLSAdded for GMPLSAdded for GMPLSAdded for GMPLS

Sub-TLVType Length Name

Sub-TLV of opaque LSA in GMPLS OSPFOpaque ←→ transparent

Numbered link = IP address is assigned to link

Un-numbered link = Router ID + Link ID

14Fig.8.14

A B C D

PATH PATH PATH

RESV RESV RESV

Label request

Originating node Destination node

Label

{301}{201}{101}Label

PATH message and RESV message

15Fig.8.17

Terminator（Destination node）

A B C DPATH PATH PATH

RESV RESV RESV

Initiator（Originating node）

{505}

Upstream label

{613} {658}

{301}{201}{101}（Downstream） label

Upstream label Upstream label

Switch setup Switch setup

Upstream labelMPLS = One-Way path

GMPLS (TDM and λ , fiber) = Bidirectional Path

Downstream Upstream Bath label can be assigned simultaneously

16Fig.8.18

Label set

Input Output Wavelength

101 201 Red115 215 Yellow120 220 Green150 250 Blue

Input Output Wavelength

201 301 Red215 315 Yellow220 320 Green250 350 Blue

Correspondence table between wavelength and label (node-B)

A B C DPATH PATH PATH

RESV RESV RESV

Originating node Destination node

{101, 115, 120, 150}

Label set

{201, 220, 250} {301, 350}

{301}{201}{101}

Assigned label

Correspondence table between wavelength and label (node-C)

If the wavelength converter is not exist, the label or wavelength which can be reserved all the links.

17Fig.8.19

Node-1 Node-2 Node-3 Node-4 Node-5

PATH (PSC)

PATH (LSC)PATH (LSC)

RESV (LSC)RESV (LSC)

PATH (PSC)PATH (PSC)

RESV (PSC)

RESV (PSC)

RESV (PSC)

LSC-LSPPSC-LSP

Hierarchization of LSPTriggered Signaling

Hierarchical Signaling

18Fig.8.20

OC-48c

OC-192ｃ

OC-192

(a) Port

(b) Component link

OC-192ｃ

OC-192ｃ

TE-link(bundling)

Port

OC-192

OC-192

TE-link(bundling)

Component link

Label

Types of data link, Port and component link

Port : Minimum physical link that cannot be divided anymore

Component link : Minimum physical link that can be divided by using time-slot or a shim label

19

Link Management Protocol : LMP

・Control channel management“LMP neighbors”= establish and manage the control channel

・Link-property correlationPort or component link?

・Connectivity certificationTest message using data link

・Failure management

“Channel status”

“Channel status Ack”

downstream

20Fig.8.21

Node-A（Local）

Node-B（Remote）

TE-link

Control channel

Link identifier

13

14

25

26

Link management by LMP

10

11

12

1

2

3

1

2

3

10

1112

Interface identifier

IP network

101

Label

102

103

101102

103

Link management protocol

Multi-layer TE enable GMPLS Node

21

FiberLayer

Layer

Packet Layer

layer topology

Packet layer topology

IP packet traffic monitor

TE Engine Extended OSPF

Extended RSVP

GMPLS Controller

GMPLS Control Unit

Packet Switching

Switching

Trade-off between Node cost and Link cost

22

Node1

Node2

Node3 Node4Node5

Node6

Node1

Node2

Node3 Node4

Node5

Node6

Fiber

LSC LSP

（a) Link cost＞Node cost

（b) Node cost＞Link cost

Node Link

GMPLS Control Flexible Network Topology

23

0 500 1000 1500 2000 25000

0.2

0.4

0.6

0.8

1Fixed Topology

Cost Reduction

Traffic Demand

Net

wor

k Cos

t (A

rv. U

nit)

Flexible Topology

Optical Crossconect Architecture

24

Input port#0

Input port#1

Output port#0

Output port#1

Wavelength Converter

Wavelength Demultiplexer Wavelength MultiplexerSwitching Block

Input port#0

Input port#1

Output port#0

Output port#1

Wavelength Converter

(a) Wavelength Converter at each output line

(b) Shared Wavelength Converter

25Figure 9.34.

Examples of AND usageSource Destination

WC WCAvailableUnavailable 1 2 3 4 1 2 3 4 1 2 3 4

1 0 1 1 0 0 1 1 0 0 1 0

Link A Link B Link C

Selected wavelength 3-3-3

1 2 3 4 1 2 3 4 1 2 3 4

1 0 1 1 0 0 1 1 1 0 0 0

Selected wavelength 3-3-1

(a) Case 1

(b) Case 2

Wavelengthconversion

Node 1 Node 2

26

WC WCAvailable

Unavailable 1 2 3 4 1 2 3 4 1 2 3 4

1 0 1 0 1 0 1 0 1 0 1 0

0 1 1 1

1 0 0 1

0 1 1 1

Source DestinationLink A Link B Link C

Link A

Link B

Link C

Available WCs at node 2

Node 1 Node 2

Available WCs at node 3

1 1

0

Selected wavelength 1-4-4

Figure 9.35.

Example of ALL scheme

27

Source Destination

0

1 2

4

3

6srlg(2, 6, 0)=1

srlg(5, 6, 0)=1

COSPF(0, 4)=1.5

COSPF(5, 6)=1

COSPF(0, 1)=1 COSPF(1, 2)=1 COSPF(2, 6)=1

COSPF(3, 6)=1.5COSPF(1, 3)=1

5

COSPF(4, 5)=1

Figure 9.41.

Network example

COSPF ( i, j ) : link costsrlg ( i, j, g ) = 0 doesn’t belong to ―srlg ( i, j, g ) = 0 belong to srlg “1”

28

Node 5

Node 2

Node 6

Fiber

λ1

λ2

Optical crossconnect

SRLG #0

Figure 9.42.

SRLG example

Node 5 → 6

Node 2 → 6Same srlg #0

29

Source Destination

0

1 2

4

3

6

5

Figure 9.43.

Example of conventional disjoint path selection algorithm

These links are same srlg No.

30

Source Destination

0

1 2

4

3

6

5

Figure 9.44.

Example of WSRLG path selection algorithm

These two link cost become large, because srlg shared link.

“ SRLG disjoint ”

Waited-SRLG Path selection

31

Single control plane

LSC path

IP router

OXC

IP router

Fig.8.22

Peer model

All the IP router

32Fig.8.23

IP router

OpticalUNI

OpticalUNI

IP control plane（Client）

Optical control plane（Server) LSC path

IP router

Overlay model

Topology reconfiguration

Midori : Automatic Self-configured Network Topology (Experimental)

Layer‐2 Switches

ON

OFFAC 

meter

MiDORi PCE

Traffic Generators

34

Conclusions for Lesson8

Basic concept of GMPLS has been described.

GMPLS is extended MPLS label to TDM time-slot

or Lambda wavelength. It introduced TE-link for

lower layer topology. Signaling, Routing and LMP

are important.