OR Project Group 1: Overall System Architecture

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High PerformanceSwitching and RoutingTelecom Center Workshop: Sept 4, 1997.

OR Project Group 1:Overall System Architecture

Isaac Keslassy, Da Chuang,Kyoungsik Yu, Greg Watson,Nick McKeown

E-mail: [email protected] Router Project: http://klamath.stanford.edu/or/

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Outline

Two-Stage Switch Overview

A WGR-based router

High-Flexibility Solution

Low-Flexibility Solution

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Generic Router Architecture

LookupIP Address

UpdateHeader

Header Processing

AddressTable

AddressTable

LookupIP Address

UpdateHeader

Header Processing

AddressTable

AddressTable

LookupIP Address

UpdateHeader

Header Processing

AddressTable

AddressTable

BufferManager

BufferMemory

BufferMemory

BufferManager

BufferMemory

BufferMemory

BufferManager

BufferMemory

BufferMemory

Switch Fabric

LinecardsLinecards

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Arbitration

160Gb/s

160Gb/s

SwitchFabric

• Line termination

• IP packet processing

• Packet buffering

• Line termination

• IP packet processing

• Packet buffering

160-320Gb/s

160-320Gb/s

Electronic

Linecard #1ElectronicLinecard #625

Request

Grant

(100Tb/s = 625 * 160Gb/s)

100Tb/s router

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Two-Stage Switch

1

N

1

N

1

N

External Outputs

Internal Inputs

External Inputs

Load-balancing cyclic shift

Switching cyclic shift

Load Balancing

First stage load-balances incoming flows Second stage is the usual switching cyclic shift

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Two-Stage Switch

External Outputs

Internal Inputs

1

N

ExternalInputs

Load-balancing cyclic shift

Switching cyclic shift

1

N

1

N

11

2

2

100% throughput for broad range of traffic types (C.S. Chang et al., 2001)

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Outline

Two-Stage Switch Overview

A WGR-based router

High-Flexibility Solution

Low-Flexibility Solution

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Passive MeshNo more arbitrations,

no more reconfigurations!

R/N

Passive mesh

123

123

R/NR/N123

123

Cyclic Shift Cyclic Shift

R R

2R/N

Passive mesh

123

123

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WGR (Waveguide Grating Router)

A Passive Optical Component

Wavelength i on input port j goes to output port (i+j-1) mod N

Can shuffle information from different inputs

1,

2…N

NxN WGR

Linecard 1

Linecard 2

Linecard N

1

2

N

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WGR Based Solution

1,

2

…N

1,

2

…N

1,

2

…N

NxN WGR

Fixed Laser/Modulator

12

N

Linecard 1

Linecard 2

Linecard N

Detector

Linecard 1

Linecard 2

Linecard N

1,

2

…N

1,

2

…N

1,

2

…N

12

N

12

N

12

N

12

N

12

N

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Outline

Two-Stage Switch Overview

A WGR-based router

High-Flexibility Solution

Low-Flexibility Solution

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Main intuition

Assume carries R/2

R

Group 1

Group 2

2R

R

2R

RR/6

2R/32R/3

2R/3

2R/3

R/6

2R/3

2R/32R/3

R/6

R/6

2R/3

High Flexibility Example

R

Group 1

Group 2

2R

2R

2R

2R

R

R

R

R R

Low Flexibility Example

R

R

R

A linecard can send morethan one to a MEMs

A linecard can send atmost one to a MEMs

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3x3 MEMS

3x3 MEMS

3x3 MEMS

3x3 MEMS

3x3 MEMS

Linecard 1

Linecard 2

Group 1

Linecard 3

3x5

3x5

Linecard 4

Linecard 5

Group 2

Linecard 6

3x5

3x5

Linecard 7

Linecard 8

Group 3

Linecard 9

3x5

3x5

Group 1

Linecard 1

Linecard 2

Linecard 3

5x3

5x3

Group 2

Linecard 4

Linecard 5

Linecard 6

5x3

5x3

Group 3

Linecard 7

Linecard 8

Linecard 9

5x3

5x3

Static MEMS Switches

Multiplexers

Fixed FiltersFixed lasers

Crossbars Crossbars

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Crossbar Solution(high flexibility)

Combines electronics and optics

Each carries up to R/G data => each linecard group can send up to R to each MEMS

Problems lots of crossbars requires lots of fixed filters

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Outline

Two-Stage Switch Overview

A WGR-based router

High-Flexibility Solution

Low-Flexibility Solution

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3x3 MEMS

3x3 MEMS

3x3 MEMS

3x3 MEMS

3x3 MEMS

Group 1

Group 2

Group 3

Linecard 1

Linecard 2

Linecard 3

Linecard 4

Linecard 5

Linecard 6

Linecard 7

Linecard 8

Linecard 9

Star Couplers

Static MEMS Switches

Linecard 1

Linecard 2

Group 1

Linecard 3

MultiplexersFull Mesh

Linecard 4

Linecard 5

Group 2

Linecard 6

Linecard 7

Linecard 8

Group 3

Linecard 9

123

5 Fixed Lasers per linecard

45

R R

5 Tunable Filters per linecard

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Full Mesh Solution(low flexibility)

Two main choices for full mesh: G2 fibers free space

Each carries up to R/G data => each linecard can send up to R/G to each MEMS

Problems mesh design can be messy star coupler loss tuning speed

Either tunable lasers and fixed filters, or fixed lasers and tunable filters