Optical Control Plane and Dynamic Optical Restoration

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© 2012 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 1

Cisco Confidential© 2012 Cisco and/or its affiliates. All rights reserved. 1

Optical Control Plane and

Dynamic Optical Restoration

Kyle HollaschProduct Marketing Manager – High End Routing and Optical Group

22-Jan-2013




• nLight Control Plane Architecture

• Background - GMPLS, WSON, and GMPLS-UNI

• Dynamic Optical Restoration

• Economic Benefits of Multi-Layer Restoration• Summary




nLight

SiliconnLight

ROADM

nLight

Control Plane

100G and Beyond

Adaptive Rate

High Performance

Information Sharing

The Network is the Database

Automation to Optimization

Complete Flexibility

No Manual Intervention

Massive Scale

Programmability, Convergence, and Scale




• GMPLS builds label switched paths across a variety of transports

• Consistent control plane for multiple switching layers /technologies. Primarily non-packet.

• Data Plane operates independently of the Control Plane

• Domain Model, Client/Server relationship.

• Defines a UNI function for cross-domain provisioning

L1L2

L3

L0




• Traditional control planes (MPLS-TE, ASON) assume ahomogenous physical layer (regen everywhere, no L0 issues)

• WSON is defined in several IETF drafts, which add these keycomponents to GMPLS

Routing and Wavelength Assignment

Distribution / collection of Channel Impairments, Path optical characteristics,other affected channels

• Impairment calculation is distributed

Reasonable computation requirements on Network Elements

No heavy reliance on DCN bandwidth, delay, and availabilityCentralized, but online computation certainly possible.


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Linear impairments

Power Budget

Chromatic Dispersion (CD)

Polarisation Mode Dispersion (PMD)

Optical Signal to Noise Ratio (OSNR)

Non linear Optical impairments:

Self-Phase Modulation (SPM)Cross-Phase Modulation (XPM)

Four-Wave Mixing (FWM)

Embedded Optical Layer Intelligence

CISCO

WSON

Foundation for Multi-layer Information Exchange

Topology

Lambda assignment

Route choices (C-SPF)

Interface Characteristics

Bit rate

FEC scheme

Modulation format

Regeneration Capability


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The Ultimate Service Velocity Enabler

• Zero Planning Wavelength Setup“Any-to- Any” designs not feasible in large networks

“On the Fly” optical validation

Find aPath

VerifyFeasibility(offline)

ProvisionRequest

Request

Provisioning

via WSON

CircuitUp

Request

via UNI

Provision

with WSON

Circuit

Up

Co-ordinate

Co-

ordinate

Service

Up

IP Transport



Achieving Multi-Layer Service Velocity

UNI-C

MSTP

CRS-3

ASR9000

UNI-N

GMPLS

UNI

• GMPLS UNI creates a circuit connection by signaling exchanges between UNIClient (UNI-C) and UNI Network (UNI-N) nodes. Typically, UNI-C nodes arerouter nodes and UNI-N nodes are optical nodes.

• Provides the ability to share and leverage information across layers



Client: IP/MPLS Control Plane

Server: DWDM WSON Control Plane

GMPLS-UNI

Operation and Benefits

• Scale

• Operational expertise

• Organizational segmentation

• Faster provisioning

R1 R2R3

O1 O2

O3

Client to Server via GMPLS-UNI

“Create a Circuit to R2”


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• Requires a touchless, flexible optical layer• Is executed by the WSON Control Plane to find and validate the

feasibility of new routes

• Leverages the GMPLS-UNI for two-way communication with a

client-based DWDM transceiver

• Is a key component of Cisco’s nLight Control Plane



• What?

Dynamic Optical Restoration is a service provided by the DWDM layer to theclient layer which enables the automatic re-routing of a failed optical circuitover a new route, triggered by a DWDM-layer event (no UNI required) or bythe client (UNI required).

• Why?

By using the same optical interface for both working and protect modes,network capex can be dramatically reduced (50% savings vs. Y-cable), whileits automated nature simplifies operations. Also, Restoration enables recoveryfrom multiple successive failures.

• How?

Colorless & Omni-Directional ROADMs combined with Tunable lasers allowthe optical layer to re-route an optical circuit in a fully touch-less manner.

Embedded WSON intelligence enables the DWDM layer to dynamicallyvalidate the optical feasibility of the new route, ensuring success andeliminating dependence on an off-line design tool.

i t d lid




Touchless Optical Layer + Embedded WSON Intelligence

ONS 15454

MSTP

Client

Colorless, Omni-Directional ROADM switches the path

Service is brought back up with the same Client and Optical interfaces, zero touches

Embedded WSON intelligence locates and verifies a new path

Edge Nodes instruct client to re-tune its wavelength

Fiber Cut!

animated slide

Client

IPoDWDMIPoDWDM




A Few Facts

• Supports ring and mesh topologies.

• Supports all node configurations with at least omni-directional functionality(colorless is ideal but not required)

• Can operate on unprotected (0+1+R) or protected (1+1+R) circuits. Protectedcircuits can be PSM, Y-Cable, or Splitter protected.

• Can be provisioned for revertive or non-revertive behavior, automatic or manualrevert.

• Currently operates “on the fly” only – no resources are pre-allocated, no routesare pre-calculated (route calculation is very fast)

• Supported on ONS 15454 MSTP Release 9.6.0.3 and later




Trigger

Activation

and

Revert (optional)

Route Discovery

and Validation

OK FAIL

Constrained OSPF algorithm

First try original wavelength, then others

Relax other constraints (future)

Link FailureSignal Failure

Re-tune interface wavelength (if necessary)

Provision VOAs and WXC ports




Trigger

Activation

and

Revert (optional)

Route Discovery

and Validation

OK FAIL







Triggers




Types of Triggers

Link failures: LOS and LOS-P

Detected by the ROADMs / Amplifiers terminating each linkLocation of problem is therefore known

Signal failures: Signal Failure and Signal Degrade

Detected by the source / destination interfaces

Location of problem is unknown

Node failures




Transponder vs. IPoDWDM

GMPLS UNI

Transponder ROADM

ROADM

Internal NE Management

Transponder-based interface

SD/SF trigger reported internal to the NE

Client-based interface (i.e. IPoDWDM)

SD/SF trigger reported via GMPLS-UNI




Restoration Details

• SD/SF criteria are defined by the interface (i.e. Pre-FEC/OTN errors)

• Only if Optical Validation is not Green, does Restoration then beginWhy? Because if optical validation is Green, the route appears to be OK, so the

DWDM interface is probably failing. No point in restoring.

GMPLS UNI GMPLS UNI




Route Discovery and Validation

Trigger

Activation

and

Revert (optional)

Route Discovery

and Validation

OK FAIL










Path

(Shortest First, with Constraints)

Wavelength

(Original First)

OK FAIL

ALL

FAIL

All Waves Up to 5 Paths

Trigger

Activation

ALL

FAIL

Path Error (today)

Intelligently relax constraints and try again (future)




• Path Diversity

Defined from UNI in terms of Node, Link or LSP-id

Link diversity only

• Optical Threshold Validation

Defined from CTC only>3 sigma confidence level (99.7%)

>2 sigma confidence level (95.5%)

>1 sigma confidence level (68.3%)

< 1 sigma confidence level (<68.3%)




Switch and (Optional) Revert

Trigger

Activation

and

Revert (optional)

Route Discovery

and Validation

OK FAIL










1. Optical Circuit Request is triggered by:

Craft Terminal

UNI interface

Control Plane for restoration

2. Routing calculation (Head Node)

3. Signalling (from Head to Tail nodes)

4. Non linear impairments calculation (Tail Node)

5. Circuit Reservation (all nodes)

6. Circuit Activation (all nodes)

Control

Plane

Data

Plane




1. Restoration, no Revert

2. Manual Revert

3. Upgrade Command

1. Working failure, Restoration,no Revert

2. Protect Failure, Restoration,no Revert

3. Working Failure, Restoration withRevert

1+R 1+1+R




Working Trail

Protect Trail

Active Trail (Carrying Traffic)

Trail Unavailable

Path in Failure (non-revertible)

Main Path

Restore Path

Protect Path (1+1)

Key to Animated Drawings




animated slide



Path Configuration: Restore no Revert

Client Client

State: Traffic is on Main path

Change: Main path fails, traffic is lost

Behavior: Restore path is calculated. Traffic moves to the Restore path

Behavior: Main path is cancelled, Restore path becomes the new Main

animated slide



Path Configuration: Restore + Manual Revert

Client Client

State: Traffic is on Restore Path, Main Path in failure

Change: Manual Revert

Behavior: Traffic does not move back to Main Path as it is non-revertible

Behavior: Traffic does move back to Main Path once it becomes revertible, and

Restore Path is cancelled




animated slide




Client Client

State: Traffic is on Main Path / Working Trail

Change: Main Path / Working Trail fails, 1+1 switches traffic to Protect trail

Behavior: Restore Path is calculated. Working Trail moves to Restore Path.

Old Main path is cancelled. Restore path becomes new Main Path.

Subcase: If 1+1 is revertive, traffic is 1+1 switched back to new Main / Working

animated slide




Client Client

State: Traffic is on Main / Working path

Change: Protect path fails. (1+1 does not switch). Protect trail is unavailable.

Behavior: Restore path is calculated. Protect Trail moves to Restore Path.

Restore path becomes new Protect Path. Old Protect path is cancelled.




L1 Protection + L3 Re-Route

Router Interface Utilization ≈ 50% DWDM Wavelength Utilization ≈ 50%

Net DWDM Utilization ≈ 25%

Slow L3 Re-Route Fast L1 Protection

No inter-layer communication Over provisioning Wasted resources




Fast L3 Protection, No L1 Protection

Router Interface Utilization ≈ 50% DWDM Wavelength Utilization ≈ 100%

Net DWDM Utilization 50%

Fast L3 Protection No L1 Protection

Better, but too much risk for some? Time to restore DWDM wave/path?

Proactive Protection




Fast L3 Protection plus L0 Restoration

Router Interface Utilization ≈ 75% DWDM Wavelength Utilization = 100%

Net DWDM Utilization 75%

Fast L3 Protection L0 Restore

Higher Utilization Fewer interfaces Lower Capex

Control Plane




• nLight Multi Layer Restoration (MLR) leverages the IP andDWDM agility to decrease the cost of running the IP/MPLS

service

• The increased agility means less standby IP capacity to

handle expected outages or better SLA for the samedeployed IP capacity

Enables Higher average IP utilization

Enables Tighter SLA’s




MTTR: Seconds to Minutes

Higher IP Interface Utilization

3 x 100G6 x 100G interfacesNormal: 140G / 300G

Failure: 140G / 200G

Avg IP util: 140/300= 47%

Premium: 45G

Best Effort: 95G

2 x 100G 4 x 100G interfaces

Normal: 140G / 200G

Failure: 140G / 100G

(Oversubscription, Best Effort loss)

Avg IP util: 140/200= 70%

Study based on major SP: 26%-40% Fewer Interfaces Required

140G

MTTR: Hours to Days

Restore




Routing Convergence

Traditional Network Protection Multi-Layer Protection

SONET/SDH Protection

DWDM 1+1 Protection

Slow but Smart

Fast - but Dumb and Expensive

BFD, IP-FRR, TE-FRRPre-FEC Proactive

Protection

Dynamic Optical

Restoration

Fast and Smart

Slow - but Smart & Efficient

Goal: Maintain SLA at Lower Cost

nLight Control Plane

Layer 3

Layer 0/1




• While MLR for optical failures allows the SP to savesignificantly, there is still need for spare capacity in the IPlayer to deal with IP layer failures

Router interface failures

Full router failures (in particular at the edge of the network)

• Future phases will extend MLR to deal with such failures

• This will more than double the savings that can be achieved




• WSON is a DWDM aware GMPLS Control Plane, made possible

by a touchless reconfigurable optical layer

• GMPLS-UNI allows multi-layer communication between the clientlayer (IP) and the server layer (optical), which enables

Fast Provisioning

Exchange of value-add information such as SRLG, latency, topology, … And ultimately…dynamic network re-optimization

• Dynamic Optical Restoration is a DWDM-layer feature thatleverages both WSON and GMPLS-UNI

• Combined with intelligent L3 protection mechanisms, it can allowhigher interface utilization, and thus fewer interfaces, and lowernetwork Capex.

• Paves the way for L3 and/or SDN driven re-optimization



Thank you.

Optical Control Plane and Dynamic Optical Restoration

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