Upload
emily-cooper
View
212
Download
0
Embed Size (px)
Citation preview
Evaluation of Possible IGP Extensions for WSON
CCAMP WG, IETF 70th Vancouver, Canada
draft-li-ccamp-wson-igp-eval-00.txt
Dan Li ([email protected])Jianhua Gao ([email protected])
Young Lee ([email protected])
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