Lappeenranta University of Technology

Valery NaumovTelecommunications Laboratory

naoumov@lut.fiTel: 05 621 3618

““Why Do We Need WDM Networks?”Why Do We Need WDM Networks?”

Growth of TrafficGrowth of Traffic

If xDSL reaches same penetration as modems then network capacity will have to increase by 100s times

Internet Traffic is growing around Internet Traffic is growing around 10% a month10% a month

Data network

volume will exceed voice in

2000-2001

By 2005 voice will be 1-5% of all

traffic

IP Telephony could be IP Telephony could be VERY BIGVERY BIG

Source: Analysis

If IP will be the dominant traffic then If IP will be the dominant traffic then optimize network design for IP!optimize network design for IP!

Internet traffic is asymmetric Telecommunication system of

today are designed to support symmetric voice traffics

1)

2)

WDM -WDM -Wavelength Division MultiplexingWavelength Division Multiplexing

Why Do We Need WDM?Why Do We Need WDM?WDM

combines multiple optical

signals so that they can be

amplified as a group and transported

over a

Each signal carried can be at a different rate (STM-1/4/16 etc.) and in a different

format (SDH, ATM, data,

etc.)

voice data videovoice data video

IPIP Frame Frame RelayRelay

ATMATMSDHSDH

WDMWDMsingle fiber.

Multi-layer NetworksMulti-layer Networks

T1304480-95/d04

TrailAP AP

Trailtermination

Network connection

TCPSNC

CPLink connec tion

Trailtermination

TCP

Client toserver

adaptation

Clientlayer

network

Trail

Client toserver

adaptation

APAP

Trailtermination

Trailtermination

Serverlayer

network

TCP

SNC

CP

LC

CP

LC

CP

LC

CP

SNC

TC P

FIG U R E 3 /G .805

E xam p le functiona l m od el

ITU-T Recommendation G.805 “Generic functional architecture of transport networks”:

A transport network can be decomposed into a number of independent transport layer networks with a client/server association between adjacent layer networks.

Optical WANOptical WAN

3 STM-16 Tx1 STM-16 Rx

Both sides of fiber ring used for IP traffic

High PriorityTrafficCannot exceed50% of bandwidthin case of fiber cut

Low priority trafficthat can be bufferedor have packet lossin case of fiber cut

AsymmetricTx/Rx lambdasthat can bedynamicallyaltered

OADMOADM

SDHSDH

Traditional SDH Restoral

Optical MANOptical MAN Carrier Routers

To Protection FiberTo Working Fiber

Packet overSDH

GigaPOPRouter

GigaBit Ethernet

University ARouter

OADM

Ethernet

Local WDM Fiber Ring Provided by Cable Company or Telecom Operator

CambrianBox

ATM

University BRouter

OADM

OADMOADM

Central Office

WDM Network R&DWDM Network R&D Common platform to provide network management, security and

support for integrated traffic Capacity usage and routing strategies

Designing survivable optical networks

Wavelength management to ensure QoS

Protection strategies for service differentiation

Development of the switchable WDM network must occur in a number of phases:

point-to-point one channel, point-to-point multichannel with WDM, network with fixed routing of WDM channels, network with protection switching capabilities in the WDM domain, and finally flexible network with switching functions for all channels in WDM crossconnects

Distributed Object-oriented Tool for Network Visualisation and Analysis (DOTNET)

EU COST 263 Project Quality of Future Internet Services

QoS characteristicsend-to end delay, jitter, throughput, reliability

Network resourcesbandwidth, buffer capacity, processing power

Resource management

state control, selection, reservation, scheduling and protection

Traffic engineeringtraffic differentiation, provision of different QoS levels

Each layer network uses its own dedicated QoS provisioning mechanism that is optimised for its particular usage