How UKLight was Built

Dr. John S. Graham

University of London Computer Centre

SuperJANET4

North WalesMAN

LeNSESWERN

Kentish MAN

NorMAN

YHMAN

EMMAN

EastNet

LMN

South WalesMAN

TVN

MidMAN

NorthernIreland

NNW C&NLMAN

Glasgow Edinburgh

Warrington Leeds

Reading London

Bristol Portsmouth

EaStMAN

UHI NetworkClydenet AbMAN

FaTMAN

UKLight Topology

CoreDirector and MetroDirector K2

CN3616

Hybrid Optical/Packet NetworksIP

Ethernet HDLC

10 G LAN PHY 10 G WAN PHY 1 G PHY

SDH (G.707)

Optical Fibre

GFP (G.7041)

packet

optical

Ethernet vs TDM

Feature Ethernet SDH

Guaranteed QOS No (Packet Switched) Yes (Circuit Switched)

Performance Monitoring

CRC Count BER

Protection None (STP?) APS

Fault Location None AIS

Access Costs Low High

Time Division Multiplexing

A Z:1 E Z:1

E

D

C

B

A

MUX

E

D

C

B

A

MUXZ

13458

Z

7 6 2

SDH Network ElementsLine Terminating Path Terminating

ADM STM-nSTM-n

DXC

STM-n

STM-n

STM-n

STM-n

STM-n

STM-n

TerminalADM

STM-n

PDH Ethernet ATM

SDH Model

RRADM DXC ADM

Path Layer Connection

Line LayerLine Layer

Section Layer Section Layer Section LayerSection Layer

Basic SDH Frame

Section

Line

PTR

SPE

3

5

27091

Payload Capacity = 2340 Bytes = 149.76 Mb/s

Larger SDH Frames

VC-4 155 Mb/s150 Mb/s

VC-4-4 622 Mb/s600 Mb/s

VC-4-4c 622 Mb/s600 Mb/s

Provisioning Example

A

D

B

E C

F3 - 5

7

9

10 -12

1

???

STM-41 – 12 (622 Mb/s)

Bandwidth Fragmentation

VC-4Drop Interface (Node F)

Ring 2 6 8

Blocked!

STM-1

STM-4

Virtual Concatenation (VCAT)

VC-4Drop Interface (Node F)

Ring 2 6 8

STM-1

STM-4

VC-3-3v

The Magic of VCAT

ProtocolClient Rate

Contiguous Concatenation

Virtual Concatenation

Ethernet 10 VC-3 20% VC-11-7v 89%

Fast Ethernet 100 VC-4 67% VC-3-2v 99%

Gigabit Ethernet 1000 VC-4-16c 42% VC-4-7v 95%

ESCON 160 VC-4-4c 26% VC-3-4v 83%

Fibre Channel 2 1700 VC-4-16c 71% VC-4-12v 95%

ATM 25 VC-3 50% VC-11-16c 98%

GFP: Functional Model

Source = IEEE Communications Magazine, May 2002

GFP: Frame Structure

Source = IEEE Communications Magazine, May 2002

Ethernet GFP SDH

Pream

ble

SF

D

Destin

ation

So

urce

Len

gth

/Typ

e

Data

FC

S

Co

re Head

er

Paylo

ad H

eader

GF

P P

ayload

FC

S

Path

Overh

ead

PTR

1

2

Ethernet Frame

GFP Frame

SONET/SDH Frame

GFP: Frame Delineation

PayloadPLI cHEC PLI cHEC Payload

Payload PLI cHEC PayloadPLI cHEC PayloadPLI cHEC

PayloadPLI cHEC

GFP: Synchronization

Hunt Presync

SynccH

EC

Mism

atch2

nd c

HE

C M

atch

cHEC Match

No 2nd cHEC Match

cHEC Match

No CHEC Match

International Lightpath Peering

• Peering at Ethernet Layer– Use non-blocking switch as a DXC– Multiple patch cords

• Peering at SDH Layer– Single physical connection

International Testbed HOPnets

• VIOLA Project (DFN)– http://www.viola-testbed.de/

• HOPI (Internet2)– http://networks.internet2.edu/hopi/