workshop - new paradigms for routing in optical networks

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Workshop - New Paradigms for Routing in Optical Networks

Efficient routing for high capacity, flexible optical networks with different classes of service

Douglas Aguiar

July 2015

2 Padtec S/A © 2015 Todos os Direitos Reservados

Summary

1. Photonic Networks

2. Classes of Service in Optical Networks

3. Routing for Optical Restoration

4. The Future and its Challenges


Summary






Photonic Networks

Photonic network Optical network able to route lightpaths

Lightpath Optical path inside a photonic nework

Even in today’s quasi-static networks ROADMs provide the efficient use of the network capacity

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Topology virtualization

With proper planning complex topologies with virtual point to point links can be established

Physical layer

DWDM layer

• Traffic growth uncertainty can be more effectively addressed (Traffic Engineering)

• Imposes greater complexity during network planning.

• Allow the planning of complex protection architectures

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ROADM site building block

Wavelength Selective Switches (WSS) are key elements for current ROADM architectures.

• Flexgrid capability (ITU-T G.694.1)

• Switching time

• Port to port isolation

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ROADM architecture

Mux

WSS

WSS

Splitter

Demux

Split

ter

Mux Demux

WSS Splitter

Mu

x

Dem

ux Line

Interface

Add/drop interface

Interconnection Structure

Direction

Transponders

Transponders

Client Equipment*

*IP Router, SDH ADM

Long reach Interface

Short reach Interface

Optical Amplification CDC

Demux CDC Mux

Optical Full

Mesh

Broadcast and Select Architecture Multifiber Patch

Cord

Single Fiber Patch Cord

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Summary






Typical classes of service

• Unprotected service (1+0)

• Restorable service (1+R)

• Protected service (1+1)

• Protected and restorable service (1+1+R)

Classes o

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Unprotected service (1+0)

Classes o

f service in o

ptical n

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1. Two unprotected services with possible protection provided by client layer;

2. Possible to allocate a 1+0 service disjoint to an already provisioned service.


Restorable service (1+R)

Classes o

f service in o

ptical n

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RSVP-TE Signaling For GMPLS Restoration LSP draft-gandhi-ccamp-gmpls-restoration-lsp-03

1. Restoration LSP is signaled after the failure of the working LSP is detected.

2. Restoration LSP may share resources with the failed working LSP.


Protected service (1+1)

Classes o

f service in o

ptical n

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1. Two disjoint LSPs are established 2. Traffic is transmitted through both paths 3. In case of failure both receivers switch to the protection LSP


Protected and restorable service (1+1+R)

Classes o

f service in o

ptical n

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RSVP-TE Signaling For GMPLS Restoration LSP draft-gandhi-ccamp-gmpls-restoration-lsp-03

1. Restoration LSP is signaled after the failure of the working LSP and/or protecting LSP; 2. Restoration LSP may share resources with the failed working/protecting LSP; 3. Restoration LSP provides protection against a second order failure for 1+1+R.


Summary






Planning for the DWDM layer

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ptical R

estoratio

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Physical Layer 1+R 100G Services

BSA (16)

FTL (10)

SPO (06)

RJO (05)

PAE (01)

BHZ (07)

CCR (14)

BSA (16)

FTL (10) 10

SPO (06) 10 10

RJO (05) 10 10 10

PAE (01) 4

BHZ (07) 4 4

CCR (14) 4 4

MNS (20) 4 4 4

1+1+R 100G Services

BSA (16)

FTL (10)

SPO (06)

RJO (05)

PAE (01)

BHZ (07)

CCR (14)

BSA (16)

FTL (10) 1

SPO (06) 1 5

RJO (05) 5 5 5

PAE (01) 1

BHZ (07) 5 1

CCR (14) 1 1

MNS (20) 5 1 1


Planning for the DWDM layer

Ro

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3

Physical Layer DWDM Layer


Efficient Network Planning

In order to maximize restoration availability and minimize cost, one can make use of:

• Efficient Routing and Wavelength Assignment algorithms

• Regeneration pools

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Summary






Technologies

• Flexible transponders

• Software Defined Networks

• Spatial Division Multiplexing

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Physical dimensions

Peter J. Winzer , Making spatial multiplexing a reality

Nature Photonics 8, 345–348 (2014)

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Flexible transponders

Advanced and flexible modulation formats allow to balance between

• Reach

• Performance

• Spectral occupation

Modulation Format

Spectral efficiency [bit/s/Hz]

Bits per symbol

OOK 0,5 1

BPSK 0,5 1

QPSK 1 2

16-QAM 2 4

DP-QPSK 2 4

DP-16QAM 4 8

2 x 1 bit/symbol DP-BPSK

1 bit/symbol OOK

2 x 2 bit/symbol DP-QPSK

2 x 3 bit/symbol DP-8QAM

2 x 4 bit/symbol DP-16QAM

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Centralized control benefits

• Simpler HW

• Open to third party development

But transport networks has always been centralized (!)

Differences are:

• Standards (??)

• Open to third party

EMS/NMS

Dados Dados Dados

Dados

CP

Dados

CP

Dados

CP

Software Defined Networks

SDN

Dados Dados Dados

Distributed control in packet networks

Centralized control via EMS/NMS in transport networks

Centralized control via SDN in transport networks

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Spatial Division Multiplexing

• Bandwidth growth need is a fact

• To achieve Tbps channels SDM might be useful.

D. J. Richardson, J. M. Fini & L. E. Nelson, Space-division multiplexing in optical fibres, Nature Photonics 7, 354–362 (2013)

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Thanks!


ROADM interfaces

• Colorless (C) Any port in any unrepeatered wavelength

• Directionless (D) Any port to any direction

• Contentionless (C) Any port in any wavelength

*Interconnection Structure

IS*

Line interfaces

Add/drop interfaces

Dir

ecti

on

A

Direction C

Directio

n E

A/D 1 A/D 2 A/D n

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ROADM Add/Drop interfaces CDC

Demux CDC Mux

Colorless, Directionless and Contentionless interfaces

Sw

Sp Sp Sp Sp Sp

Sw Sw Sw Sw Sw Sw Sw Splitter Coupler

Splitter WSS

8x5

Mu

ltic

ast

Swic

th

Co

lorless an

d D

irection

less in

terface

Sw

Sp Sp Sp Sp Sp

Sw Sw Sw Sw Sw Sw Sw

Tran

spo

nd

er

Tran

spo

nd

er

CD interface for 8 channels in a 5 degree ROADM Node

CDC interface for 8 channels in a 5 degree ROADM Node

To/F

rom

dir

ecti

on

B

To/F

rom

dir

ecti

on

A

Fro

m d

irec

tio

n B

Fr

om

dir

ecti

on

A

To d

irec

tio

n B

To

dir

ecti

on

A

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Flexible transponders and networks

• Flexible grid

• Superchannels

• Network defragmentation

• Interference in Colorless interfaces

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workshop - new paradigms for routing in optical networks

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