roadms & control plane for research & educational · pdf fileroadms & control...

ROADMs & Control Plane for

Research & Educational Networks

Terena NGN Workshop, April 4, 2008, Munich

Thomas Schneider

Business Development Manager EMEA

© 2008 ADVA Optical Networking. All rights reserved. ADVA confidential.2

Agenda

�NRENs

�ROADMs and Open GMPLS Control Plane

�ROADMs and 40G


National Research & Educational Networks NRENs – A quick Technical Analysis

� Reach w/o 3R: 1000…2000 km

� Capacity: 40 wavelengths typically

� High bit-rate services

� 10G LAN PHY, STM-64

� 40G required today

� 100G already considered

� InfiniBand may come up

� Flexibility requirements

� Control Plane, UNI/NNI,

possibly support for UEN/UCLP

� ROADMs (Degree-8)


Agenda

�NRENs


�ROADMs and 40G


ROADM Architectures

Broadcast and Select Mux / Switch / Demux

N

VOA

Add / Drop

Switches

λN

λ1

λN

... ...

λ1

Switched (iPLC)

1 N

1 NDrop

Add

N 3dB1 x N iPLC

N

1 NDrop

1 NAdd

3dB 3dBWB

Switched (WSS)

1 x N WSS

1 NDrop

1Add

N1 x N WSS

N

WB: Wavelength Blocker, WSS: Wavelength-Selective Switch


Degree-N ROADM

ROADM

Single WDM Channels

OMS (East)OMS (West)

N

SW E N S

W E

...

...

Degree-2 ROADM

Higher-Degree ROADM

k x N WSS

1 NDrop

1Add

Nk x N WSS

N

Higher-Degree ROADMbased on WSS


Drop

Output

. . .

AW

GD

MX

AW

GM

UX

VOA

Switch

Monitor PD

Express

Output

Express

Input

Common

Output

Common

Input

Add Inputs

iPLC-based ROADM

AWG leads to typical filter characteristic

λ1 λ2 λ3

Wavelength

Attenuation

Spectral Characteristic

Channel Selectivity


Higher-Degree ROADM: MEMS

� Mechanical switches (MEMS)

� Multi-degree switching possible (In1/2/N → Out)

Out

In N

In 1

Mirror

Array

Spectral Characteristic

(Flat Top)

∆f [GHz]

Insert

ion L

oss


ROADM (and GMPLS) Applications

� Re-configure the network

� Adapt to changing network and customers’ requirements (slow)

� Protection and restoration (meshed networks!) (fast)

Enabled through GMPLS Control Plane:

� Topology discovery (routing), signalling, path computation

� Management of connections between GMPLS nodes

� Access to any channel anywhere – single-channel add/drop

� Enable centralized L3 networks (with single L3 hub)

� Power level equalization, increase of transparent field lengths

� Increased visibility of installed infrastructure


Equalization with ROADMs

Dynamic

Channel

EqualizerDrop Add

Pre-Amplifier Post-Amplifier

� Enabled through monitor

taps, VOAs/SCEs, and

Control Plane signaling

� Can eliminate up to 5dB

of ripple/tilt

� Necessary / enabler for

regional installationsλ1 ... λN

+6dBm

0dBm

λ1 ... λN


Network Re-configurations

It’s difficult to share / re-use transponders orcolored client I/Fs

100%

120%

140%

0% 10% 20% 30% 40% 50%

Relative Amount of dynamic PathsT

ota

l C

apacity

Ring

Mesh

ROADM

T T TT

Flexible Add/Drop

Passthru

Transponders

Offloading Core Routers

Network Capacity

Large Core RingLarge Core Ring


Centralized Layer-3

Photonic transmission gear is protocol and bit rate agnostic –

No need to provide protocol gateways for L3 at client sites

Centralized L3 Device

Client ClientClient

ClientClient

Single-channel

Add/Drop of any

Channel anywhere

Logical IP topology


Restoration

W1 (failed)

W3

W2

W4

W5

W6

Restored Traffic

Fast, distributed topology discovery, signalling, routing – but

� ROADMs can provide a restoration path through a network, but today

they do not perform the end-to-end switch-over

� ROADMs may need to provide wavelength conversion

� Uncertainty w.r.t. link length – complex link engineering

IL

SOALOA

SOALOA

MEMS

Switch

Matrix

CW

CW

(Red-shifted)

All-optical Lambda conversion

LOA – Linear Optical Amplifier


RAYcontrol® GMPLS Control PlaneIntelligent optical networking

� Provisioning

� Simplified, automated

� Agile, fast (auto-discovery, signalling, routing)

� Integrated network management (synchronized databases)

� Network efficiency

� Higher asset utilization

� Automated network

inventory and reuse

� Efficient restoration

� Network evolution

� Interoperability

� New services and operation modes (UEN, UCLP)

� New architectures (true meshes)

Control Plane

ForwardingPlane

UNI

UNI

NNI

NNI

CCI

Connection Controller (CC)


Control Plane Building Blocks

Routing

� OSPF (reachability)

� OSPF-TE (traffic engineering)

� GMPLS-OSPF (optical extensions)

Path Computation

� Shortest Path (Dijkstra)

� Kth-Shortest Path (Yen)

� Constrained Shortest Path, CSPF

Signaling

� RSVP (reservations)

� RSVP-TE (tunnel LSP setup)

� GMPLS-RSVP (optical extensions)

� IETF standard link-state routing protocol

� Supports link auto-discovery; extended for GMPLS

� Supports network-wide synchronization; do.

� IETF standard soft-state signaling protocol

� Supports hop-by-hop signaling; extended for GMPLS

� Supports resource reservation and configuration; do.

� How to get from Ingress point to Egress point?

� Services have many characteristics that affect path selection

� CSPF, adds constraints to standard Dijkstra algorithm


ROADM Support

� End-to-End Service Power Equalization

� ROADMs include per-wavelength power monitoring

� Optical services may traverse multiple ROADM nodes

� Nodes equalize automatically in sequence, GMPLS-controlled

� Multi-Degree Optical Switching

� MD-ROADMs, when deployed in a mesh, lead to an

exponential increase in available paths

� MD-ROADM enables pure OOO switching

� Wavelengths are not converted, ingress / egress waves must match

� Additional constraint considered in CSPF path selection


D

A

B

C

Path Setup

E1 E2

R2

E3E4

R1


Equalization Process

Path

[1533.47][1549.32][1549.32] [1560.61]

Resv

Data Flow

[DN EQ]

[UP EQ][UP EQ][UP EQ] [UP EQ]

[DN EQ][DN EQ][DN EQ]

Path Setup phase …

… followed by Path Equalize phase

Ingress Equipment

• Set data rate

• Set protection

• Connect add

• Connect drop

Egress Equipment

• Set data rate

• Set service type

• Set protection

• Enable line port

• Enable trib port

…

Transit Equipment

• Connect UP – DN

• Connect DN – UP

3R Equipment

• Set UP data rate

• Set DN data rate

• Enable UP trib

• Enable DN trib

• Connect UP/drop

• Connect DN/add

• Connect DN/drop

• Connect UP/add


GELS – Ethernet Support

GMPLS-controlled Ethernet Label Switching

� Ethernet as just another transport technology

� VLAN or VLAN+MAC becomes GMPLS label

� Labels identify end-to-end path, distributed via signaling

� Ethernet services become regular GMPLS tunnels

� Integrates Ethernet into GMPLS management framework

� Same tools (routing, signaling) used by optical GMPLS

� Eliminates need for other control mechanisms (RSTP, etc.)

� Benefits

� Traffic Engineering for Ethernet – explicit control over path

� Automation – 802.1ad/ah (PB, PBB) forwarding tables populated

via CP signaling rather than manually


Agenda

�NRENs


�ROADMs and 40G


� Linear Effects

� Attenuation, leading to noise (ASE) – 6dB less sensitivity*

� Chromatic Dispersion, CD – worsen by factor 16*

� Polarization-Mode Dispersion, PMD – worsen by factor 4*

� Nonlinear Effects (SPM, XPM, FWM, SRS, SBS)

� Added signal distortion

� Interaction with CD

� Nonlinear crosstalk

� This is getting even worse for 100G!

CD is getting worse by a factor of 100

(100G vs. 10G)…

*) 40G NRZ as compared to 10G NRZ

40 Transmission Constraints

Nois

eLim

it

Non-linear Lim

it

Launched Channel Power [a.u.]

Num

ber

of S

pa

ns [

a.u

.]


40G Modulation Format Comparison

OSNR(1)

CD(2)

PMD(3)

50GHz

ROADMs(4)

~16dB

±150ps/nm

2.5ps

0

+

+

±0dB

+

~15dB

±50ps/nm

3.5ps

+

+

–

4dB

+

~12.5dB

±50ps/nm

2.5ps

0

0

0

3dB

0

~13.5dB

>5000ps/nm

>10ps

–

–

+

0dB

–

SPM / NL

(1) Back-to-Back @ BER=1E-3 (2) w/o TDC (3) 1dB Penalty (4) Penalty for 6 ROADMs (5) of 10G NRZ OOK

Upgrade(5)

Re

Im PolMux-DQPSK

Phase Noise

Re

Im Duobinary

Re

Im CSRZ

Re

Im DPSK


Comparison of 40G Techniques

Metro core and

regional links with

many ROADMs,

upgrades of 10G

40G Duobinary

Regional links

w/ only few

ROADMs but

medium-hi PMD

requirements,

upgrades of 10G

40G CSRZ

Long-haul with

ROADMs and

high PMD,

careful with

LH 10G overlay,

accumulated

phase noise,

non-linearity

Regional and

long-haul links

with only few

ROADMs,

careful with LH

10G overlay

Application

Area

40G PM-DQPSK40G DPSK

Po

we

r [d

B]

-60

-40

-20

0

2 1 0 1 2

Normalized Frequency

NRZ-Duobinary

CSRZ (OOK)

NRZ (OOK)

2 1 0 1 2

Normalized Frequency

RZ-DPSK

50%RZ (OOK)

CSRZ-DQPSK


� Implementation

2004 - 2007

�Purpose

Test of advanced network features

�Applications

10GbE LAN PHY, GFP, and 40G tests

�Key performance

Early availability of relevant future features

ADVA 40G and ROADM References

Köln

Alcatel

40G

ADVA

40G

40G

Siemens

hiT7070

ADVA

4x10G

10G

Siemens

OTS4040

ADVA

40G

40G

Siemens

OTS4010

ADVA

4x10G

10G

St. Augustin

AD

VA

AD

VA

� Implementation

2005

�Purpose

High-end test-bed

�Applications

eVLBI (Radio astronomy), HD Video

�Key features

�Open GMPLS Control Plane

�Multi-degree ROADMs

Vertically Integrated Optical

testbed for Large Applications

Thank You!

[email protected]

IMPORTANT NOTICE

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