Evaluation of Possible IGP Extensions for WSON

CCAMP WG, IETF 70th Vancouver, Canada

draft-li-ccamp-wson-igp-eval-00.txt

Dan Li (danli@huawei.com)Jianhua Gao (gjhhit@huawei.com)

Young Lee (ylee@huawei.com)

Objectives

• Examine required information for wavelength path computation

• See how much is “static”– Hardware configuration

• See how much is “dynamic”– Changes with network use

• Examine what would happen if an IGP was used for information distribution

• Help WG decide whether it is good or bad to use an IGP

What Information?

• draft-bernstein-ccamp-wavelength-switched-02.txt– Section 5.2 describes the subsystem properties which

are needed for path computation

Wavelength existence

Wavelength conversion/connection

Add/Drop availability

Per-fiber wavelength availability information

Static

Semi-static

Semi-static

Dynamic

Why Consider Using IGP?

The IGP that is already used to advertise TE information within the WSON is a candidate solution to distribute the wavelength constraint information

But there are concerns and requirements to protect the IGP…

Requirements for Use of IGP

• Additional information advertised must be small

– Must not affect the performance of IGP

• Must scale to support different wavelength multiplexer systems

– Large number of lambdas

• Should be functional for other label types

– There are similar possible uses in TDM devices

• Should support all kinds of wavelength conversion capabilities

– Input interface and lambda to output interface and lambda

Example Node for Study

WavelengthSwitch

WavelengthConverter

(limited capacity)

Add/Drop

Direction 1

Direction 2

Direction 3

Direction 4

160λ

160λ

160λ

160λ

Glass-through

Assessment ExampleConsider a WDM node with 4 directions and 160λ per fiber

• Wavelength configuration information per fiber:(4-byte lambda label as defined by lambda label draft)

160 * 4 = 640 bytes (static information)•Potential Wavelength Connectivity Information

(one bit for each λ’s connectivity to each λ on each other fiber)

3 X 160 X 160 / 8 = 38400 bytes (semi-static)• Add/Drop Availability

(one bit for each λ)

160 / 8 = 20 bytes (semi-static)• Wavelength availability status information per fiber:

(one bit represents the status of each λ)

160 / 8 = 20 bytes (dynamic)

Observations

• Size of dynamic data is not an issue

• Size of static data is not significant

• Size of semi-static data is a concern– Several ways to compress/reduce data– Maybe it is so stable that it should be treated

as static

Next Steps

• Work with other drafts for consistency

– “wson-frame”, “wson-info”, “lambda-label”

• More research on scaling issues

– Document methods for data reduction

– Examine ways to reduce flooding

• Comments are always appreciated