Optical Packet Switching the technology and its potential role in - - PowerPoint PPT Presentation

1

ld@com.dtu.dk Zagreb 210503

Optical Packet Switching

the technology and its potential role in future communication networks

Results from IST project .

Lars Dittmann COM – Technical University of Denmark ld@com.dtu.dk

2

ld@com.dtu.dk Zagreb 210503

What is the next generation photonic network?

(different targets different timescales)

• Extension to current SDH/SONET network with

LCAS, ASON, GMPLS, GFP, etc. ?

• Bitrate and protocol transparent optical datapath

with electrical control and management ?

• All-optical network with optical control,

information processing and routing ?

3

ld@com.dtu.dk Zagreb 210503

Why do we need the next generation optical network ?

• for cost reduction reasons (cost reduction potential seems

larger for optics than for electronics)

• to increase network efficiency and utilisation
• for resource savings preserving network reliability and

availability

• for better network control for fast and efficient configuration
• f connections (reduction of manual interventions)
• to increase network flexibility and responsiveness to dynamic

traffic demands/changes

• because an optical network is in line with a simplified core

structure with more complex and intelligent flow handling at the edges (which was the original idea of the MPLS concept)

4

ld@com.dtu.dk Zagreb 210503

Technological challenges

possible optical connection types

Network Resources

Virtual Connection Oriented Connection- Less Burst Switching Packet Switching

Packet and Burst Switching

Virtual Leased Lines & VPNs Connection Oriented

Circuit Switching

Leased Lines

5

ld@com.dtu.dk Zagreb 210503

Technological challenges

packets vs. circuits

Circuit Flow 100ns 1µs 10µs 100µs 1ms 10ms 100ms 1s 100 1k 10k 0.1M 1M 10M 0.1G 1G 4 G b p s B i t r a t e 2 . 5 G b p s Burst Packet

Transfer Time Transaction Size (Bytes)

10s 1 G b p s

6

ld@com.dtu.dk Zagreb 210503

Why packet switching

• Primarily a traffic engineering tool!
• Seen as the final goal for network

flexibility, however must be justified

• Packet based operation at application level

and transport level should not be mixed up!

• Potential new methods for network

resilience in packet based networks (path set-up without resource reservation)

7

ld@com.dtu.dk Zagreb 210503

Optical Burst and label Switching

potential step towards optical transport plane

Switch control Add/Drop control Control plane interface c 1 n Out Fibre 0, 1,..., n

WDM Mux 1

c 1 n In Fibre 0, 1,..., n

WDM Demux 1

Burst Assembly/Disassembly Buffering

Drop Ports Add Ports IP Router

Switch Control (Label Swap)

O E O E

Labels in Labels out O/E Conversion Optical Domain Electrical Domain Data interfaces

Optical Space Add/Drop Switch

8

ld@com.dtu.dk Zagreb 210503

• DAVID = Data and Voice Integration over DWDM
• A European research project

– Financially supported by the EU commission – IST program

• Goals

– Develop concepts and technologies for future, optical networks – Traffic engineering in packet-over-WDM based networks – Control systems for optical networks

• Timeline

– Start July 2000, end October 2003

9

ld@com.dtu.dk Zagreb 210503

DAVID Project partners

• Companies

– Alcatel, CIT (F) – Alcatel, SEL (D)

• Network operators

– BT (UK) – TELENOR (N) – TELEFONICA (E)

• Research centers

– IMEC (B) – COM (DK)

• Universities

– NTUA (G) – University of Bologna (I) – Politechnica de Torino (I) – LRI (F) – INT (F) – University of Essex (UK) – UPC (E)

10

ld@com.dtu.dk Zagreb 210503

Overall architecture

• Key components

– OPADM – optical packet add / drop multiplexer – Hub – Gateway – OPR – optical packet router

• Coverage

– MAN and WAN

• Control

– MPLS-based MAN WAN

11

ld@com.dtu.dk Zagreb 210503

Hierarchical MPLS concept

• An MPLS based architecture for mixed-technology

networks

• Traffic optimized/conditioned between levels
• Levels of various granularity

Level Bandwidth granularity Electrical MPLS Packets Optical MPLS Larger packets Wavelength routed Wavelengths

+ wavelength bands, fibers

12

ld@com.dtu.dk Zagreb 210503

The optical packet MAN

• Topology - interconnected physical DWDM rings
• Each physical ring -> several logical rings
• Ring nodes – OPADMs - provide

– Ring connectivity – Legacy network interfaces

• Inter ring traffic controlled by a hub

O p tic a l s w itc h

R N 1 R N 5

M A C p ro to c o l M u lti-rin g s D w d m W a v e le n g th b a n d s O p tic a l p a c k e ts O P A D M & le g a c y in te rfa c e s M a n a g e m e n t o f th e flo w s

W id e A re a N e tw o r k

IP , E th e rn e t, ... IP , E th e r n e t, ... IP , E t h e r n e t, ...

L e g a c y i n te rfa c e B a n d d e m u x B a n d m u x O p tic a l p a c k e t A d d /D ro p m u l ti p l e x e r ( O P A D M )

Hub OPADM OPADM d a t a s l

• t

d a t a s l

• t

data slot d a t a s l

• t

d a t a s l

• t

data slot d a t a s l

• t

d a t a s l

• t

data slot 1

• ...

13

ld@com.dtu.dk Zagreb 210503

– permutations to use are based on measurements of "demand" – each timeunit Hub switches traffic between rings – permutations to switch multislots between (logical) rings

The metro part: MAN

• Hub functionality:

ring 1 ring 2 ring 3 ring 4 ring 1 ring 2 ring 3 ring 4

?

ring 1 ring 2 ring 3 ring 4 ring 1 ring 2 ring 3 ring 4 1 2 3 1 3 3 2 3 4 3 2 1 3 4 1 2 1 2 4 1 2 4 4 4 ... ... ... ... ring permutation slot input ring

? ? ? ?

14

ld@com.dtu.dk Zagreb 210503

Packet formats

For synchronisation reasons fixed size packets (at transport level) is preferable for small units (nano-micro sec). Variable service units handled by sequence of fixed size packets.

15

ld@com.dtu.dk Zagreb 210503

Ring node evolutionary steps

(cost vs. flexibility)

DAVID MAN with active OPADMs

DAVID MAN with passive DAVID MAN with passive DAVID MAN with passive DAVID MAN with passive OPADMs OPADMs OPADMs OPADMs

“Now” “Future”

16

ld@com.dtu.dk Zagreb 210503

Administrative challanges

ASON vs. GMPLS/MPS

• Apply the dynamic configuration of service

layers to the transport layer(s)

• Integrated control of layers in the network
• Optimised use of the individual layers
• Standard proposals from: IETF, ITU-T, OIF
• Protocol centric solutions (IETF) vs.

architectural centric solutions (ITU-T)

• Multi-layer resilience concepts

17

ld@com.dtu.dk Zagreb 210503

Administrative challanges

IETF : MPLS/MPS

level 0 (MAN) level 1 (EMPLS) level 2 (OMPLS) level 3 (MPS) edge edge edge edge router router router router WAN WAN WAN WAN MAN MAN MAN MAN

Technology hierarchy

18

ld@com.dtu.dk Zagreb 210503

When will the next generation of photonic networks become a reality

• Significant effort needed to lower the cost and enable

OAM functions of optical components (higher integration and automatic packaging)

• Better understanding of traffic and performance issues in

core and metro networks needed to evaluate cost and reliability issues in current proposals.

• Gain consensus on administrative concepts and standard.
• Optical networks must become digital – 3R in all elements

as first process

19

ld@com.dtu.dk Zagreb 210503

When will the next generation of photonic networks become a reality

• Dynamic administration of pseudo optical

networks (SONET/SDH) in 2-4 years.

• All-optical networks functions in the data plane
• btainable in 5-10 years
• All-optical operation in all layers is not realistic

with current know technology (and might never be)

20

ld@com.dtu.dk Zagreb 210503

IST DAVID info @ david.com.dtu.dk

Public demo in October in relation to Public demo in October in relation to PS´2003 (photonics in switching) in Paris PS´2003 (photonics in switching) in Paris

and

(NGPN deliverables @ www.ngni-core.net)