gmpls lambda aware - cisco.com · the s-gmpls model is a hybrid model between the full-peer and...

© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 1

GMPLS Lambda aware

Dirk Schroetter, Consulting Systems Engineer


Agenda

Defining the goal based on the trends

Intrumenting the DWDM Layer

State of the Art

Cisco Approach

Summary


Defining the goal based on the trends


Overall Traffic Growth Impact Market trends:

Dramatic IP increases in Metro traffic due to Video + Ethernet business services

Customers demand rapid transport service turn-up

Providers are leveraging Ethernet to provision a variety of services

Video key driver

Drives requirements:

Service Transparency

Topology Flexibility

Simplified, Cost Effective Operation

Global IP Traffic—By Segment

For Perspective:

1 Exabyte = 5 X All the World‟s Printed Matter

5 Exabytes = All Words Ever Spoken


2006

Core Metro Access

Core Metro Access3.8 EB/mo 4.2 EB/mo 4.2 EB/mo

19.2 EB/mo 28.5 EB/mo 29.5 EB/mo

Core Grows Fivefold, Metro Sevenfold

Source: Cisco, 2008

2011


What should an optical control plane do?

L1L2

L3

L4

L5

L6

L7

L8

L9

L10L11

L12

L13 L14

L15

L16 L17 & L18 (l)

WLC

R1

R2

R3

N2

N1

N3

N4

N5

N6 N8

N7

Router

Fixed OADM

Multidegree ROADM

Multidegree ROADM(omnidirectional)

Elements of an OCPResource Discovery

• Network Elements

• Links

• Link Properties

• Optical Transmission Parameters

Topology Discovery

• Nodes

• Links

• Hypothetical Connectivity Matrix

Traffic Provisioning

• Centralized vs.rdistributed

• Pre-computed vs. On-the-fly

• Regeneration support

• Intelligent interworking with client layer

Traffic Restoration

• In cooperation with client layer(s)

• Pre-computed vs. On-the-fly

Network Restoration

• Use of Regens, Multi-Degree nodes

Network Optimization

• Computationally hard

Increasing Complexity


Manual Patching Manual provisioning of each node

Manual patching of each node

High OpEx

Truck rolls to every node

With ROADMs and WXC Manual provisioning via NMS

Autopatching via intermediate ROADMs and WXC

Lower OpEx

More service flexibility

Truck rolls to end points

Dynamic Service Activation with Colorless, Omnidirectionality and S-GMPLS Auto provisioning wavelength on demand

via S-GMPLS

Auto patching via ROADMs and WXC

Lower OpEx even further

No truck rolls

Towards Dynamic Service Activation

1

432

6

5

Manual Provisioning Manual Patching

6

8

75

Manual PatchingManual Provisioning

1

432

DynamicService

Activation


Cisco‘s view on OCPs

If IP is driving the demand in the transport network, IP models should take precedence

Statistical muxing, Traffic Management, QoS

For the forseeable future, IP will be dominating the traffic growth, but other client layers continue to exist

Multiple client layers need to be supported

DWDM needs to be intelligent

One size does not fit all

Topology awareness is beneficial for some client layers, others don„t need it

Long-term connections vs. Short-lived ones


Instrumenting the DWDM Layer


Instrumenting DWDM for OCPs

Instrumenting the DWDM layer

Tunability

• Optical channels can be moved and changed to different wavelengths completely via software

Colorless

• Ability to change the wavelength aspects of these devices without moving any physical fibers

Omni-Directional

• A fixed fiber port interface directed to any of the degrees within the ROADM node

Impairment-aware

• DWDM system must be able to measure optical impairments

✔ ✔Release 9.2

✔Update in

R 9.2

Open, requires

work in ITU


Use of Omni-Directionality

Oakland

Fremont

Pleasanton

San Francisco

Burlingame

Hayward

Santa Rosa

Fairfield

A

B

CD

AB

C

D

Reaction to a Fiber Cut no longer requires a Site visit

Omni-directional switching extend network flexibility

– Channels can be re-routed to respond to network failures, congestions or maintenance


Oakland

Fremont

Pleasanton

San Francisco

Burlingame

Hayward

Santa Rosa

Fairfield

A

B

CD

AB

C

D

Colorless allows to use different wavelengths for the different sections of the optical path to avoid congestion situations

R

Use of Colorless


Applying Colourless with Tuneable Optics

One interesting feature, enabled by colourless ROADMs, is equipment protection

1:N protection can be used to protect N interfaces with 1 spare interface, provided that the system supports the following features:

Tuneable TXTs

Colourless ROADMs

Protection Mechanism:

1. All the line-cards are working properly

2. A failure happens on red wavelength

3. The system tunes (on both sides) the spare channel on the proper wavelength

4. When the original interface has been repaired the systems reverts to normal operation

5. And it is ready to protect a new wavelength…

6. …green one this time

DWDM(MSTP)

Client Equip.(CRS-1)

Line Cards

Possibility for large savings


Approaches to OCP design


Hide Network Details from Other Departments

and Customers

IP Control Plane w/Intelligence and

Lowest OpEx

AugmentedModel hybrid of peer and

overlay

Optical Control Plane Models

Overlay Model

(OIF/ASON)

Augmented

S-GMPLS Model

Peer/Integrated GMPLS Model

(IETF)

Optical Control Domain


OIF/ITU ASON Overlay Implementation

Routers peers with each other

Transport network is not visible from routers

Transport setup request can be initiated by routers

End-to-end LSP Set up

Call connection module like PNNI ATM ILMI

Layer 1 view

UNI-CEMS

I-NNII-NNI

IP/MPLSIP/MPLS

UNI (OIF)UNI (OIF)

UNI-C

UNI-N

E-NNI UNI-N


IETF GMPLS Peer Implementation IETF

Routers and transport NEs are peers

GMPLS between router and optical NE

GMPLS between optical NEs

End-to-end LSP set up

Layer 3 view on the world

EMS

GMPLS NetworkGMPLS

DWDMDWDM

GMPLSIP/MPLS

IP/MPLS


IETF Segmented-GMPLS Peer Model

The S-GMPLS model is a hybrid model between the full-peer and overlay models

Border router received routing information from the optical devices as well as routers

The Border router keeps the optical and router domain topology information in segmented routing tables

No routing information from the router region is carried into the optical region

Logical separation on the border router

Border Router

GMPLS Network

GMPLSGMPLS

GMPLSGMPLS

GMPLS

Router Topology

Optical Topology

IP/MPLS

IP/MPLS


IETF Segmented-GMPLS PCE Model

IETF PCE area boarder router module

Path Computation Element (PCE)

Lives on a server

Request PCE

Explicit path or pump the path (ingress and egress)

GMPLS Network

GMPLS GMPLS

GMPLSGMPLS

GMPLS

IETF PCEIETF PCE

IP/MPLS

IP/MPLS


Does the IP layer need optical topology?

Not all of the nodes

Border routers

PCEs

But as has been shown in all other cases:

Topology hiding can lead to suboptimal routing decisions

Topology hiding requires a much more intelligent UNI (SRLG)

Some form of topology required to support EROs (Explicit Route Objects)


Topology awareness helps in this case

1. Request connection from A to C by optical user (via EMS) orIP user (via CLI), specifying:

Ports at both ends (optional)

Route diversely from a set of links (subnets)

Route the same way as another link (part of link bundle add/remove?)

2. The network will find ports at A & C as well as an optical path that respects these SRLG constraints

3. The network will then set up that path end to end

(b) Good Mapping

A

B

C A

B

CX

L3 Topology L0 Topology (a) Bad Mapping

Y


State-of-the-art


A quick review of MPLS

Routers or switches that handle MPLS and IP are known as Label Switch Routers (LSRs)

LSRs at the edge of MPLS networks are sometimes referred to as Label Edge Routers (LERs)

Ingress LERs are responsible for classifying unlabelled IP packets and appending the appropriate label.

Egress LERs are responsible for removing the label and forwarding the unlabelled IP packet towards its destination.

Barcelona

Delmenhorst

LSR

LSRLSR

LSP

LSR


Enter GMPLS: Nested LSPs, more NEs

Unified Control PlaneGMPLS

IP Routing ProtocolsWith Extensions

OSPF, ISIS

Label Distribution ProtocolsCR LDP, RSVP TE

MPLS TERSVP TE

Forwarding Plane

PSCDomain

GMPLS Domain

TSCDomain

OTN

LSCDomain

FiberDomain

TELSP

TELSPSONET

SDH NE

SONETSDH NE

OXC

OXC OXC

OXC

Router

Router

Router

Router

SONETSDH NE

SONETSDH NE

RouterRouter

RouterRouter Switch

Switch

Switch

Switch

An LSP must start and end on the LSRs of the same type.

Nested LSPs

FA-LSC LSPFiber

FA-TDM LSPLambda

FA-PCS LSPTDM

LSP Packet


GMPLS Overview

GMPLS supports five types of interfaces:

PSC - Packet Switching Capable: IP/MPLS

L2SC - Layer-2 Switching Capable: ATM, FR, Ethernet

TDM - Time-Division Multiplexing: SONET, SDH, G.709 ODUk

LSC - Wavelength Switching: Lambda, G.709 OCh

FSC - Fiber Switching

GMPLS extends MPLS/MPLS-TE control plane

LSP establishment spanning PSC or L2SC interfaces defined in MPLS/MPLS-TE control planes

Extensions primarily driven by characteristics of TDM/LSC/FSC

GMPLS extends these control planes to support ANY class of interfaces (i.e. layers)

ASON may and WSON does use GMPLS


ASON Control Plane vs. Transport Plane

ASON only deals with the signaling & abstracted transport elements between subnetworks and at the UNI/NNI border


ASON Protection

1. Working & Protect path are set up2. Link failure -> NEs signal to CP3. CP signals ingress & egress NE

Classical TDM 1+1 protection


ASON Restoration

1. Working path is set up2. Link failure -> NEs signal to CP & working path is released3. CP calculates new path, possibly using crankback4. CP signals new working path to subnetworks

Classical Rerouting & Restoration


WSON Operation

Establish lighpath through PATH message

Explicit routes supported

WSON supports wavelength converters (e.g. Regens)

L1L2

L3

L4

L5

L6

L7

L8

L9

L10L11

L12

L13 L14

L15

L16 L17 & L18 (l)

WLC

R1

R2

R3

N2

N1

N3

N4

N5

N6 N8

N7 Router

Fixed OADM

Multidegree ROADM

Multidegree ROADM(omnidirectional)

Path (R3)Path (N1,N2,N4,N6,N8,R3)Path (WLC,R3)


Comparing Control Planes

ASON GMPLS WSON MPLS

Networks

Client SDH/PDH (OTN?)IP, SDH, PDH, Ethernet, OTN,

DWDM

Same as GMPLS

IP

Server SDH/PDH (OTN?)SDH, PDH,

Ethernet, OTN, DWDM

(SDH, PDH, Ethernet) OTN,

DWDMNone

Protection 1+1 1+1, 1:1, 1:n 1+1, 1:1, 1:n 1+1, 1:1, 1:n

Restoration Yes, Crankback Yes Yes Yes

SummaryMainly SDH/PDH focus, “Next-Gen”

SDH

Introduces concept of

„Server Layer Network“ to

MPLS

Mainly DWDM focus, still

architecture battle

Basis for MPLS-TP, extended through GMPLS


Cisco approach


Cisco GMPLS lambda aware

Control Control

IPoDWDM Open Network (e.g. SDH)

ControlGMPLS

aware

Control

UNI for OCh CC

UNI for OCh NC

UNI for OCh NC

Control


Cisco GMPLS Lambda aware

Control plane will provide:

UNI for IP and other client layers

Toplogy Information (to support EROs)

Coordinated OAMP between the layers

GMPLS Lambda aware Control Plane

IP Client Layer Other Client Layers

UNI Topology Info OAMP


GMPLS DWDM aware Initial Phase

LSP Provisioning

DWDM Aware algorithm (linear / non linear impairment)

GMPLS extension (OSPF-TE, RSVP-TE)

OSPF

UNI

UNI

UNI


GMPLS DWDM aware second phase

Optical Restoration

Network Optimization

Optical Auto-bandwidth

Protection Protocol

Protection Protocol


Optical Auto-Bandwidth Vary channel count as

trunk load changes

Router measures utilization for L2 link bundles (LAG)

If utilization is high – request the set up of another wavelength from L0 and add it to the link bundle

Original topology retained to avoid convergence issues – channel add/remove within existing link bundles


Summary


Summary

To fulfill its promise, an OCP must reside on an intelligent optical layer

Tunability, Colorless and Omnidirectionality are a must

If IP is king, an augmented peer model makes sense

Support for EROs, MPLS FRR support, Rearchitect Protection in the core

Standards are evolving and not yet finalized

... Good opportunity for you to make your voice heard in IETF

... ASON and OTN switching model of very limited use when you deal with IP

Cisco takes a balanced and phased approach

gmpls lambda aware - cisco.com · the s-gmpls model is a hybrid model between the full-peer and...

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