1_4_FunctionAndFeatures

Section 1 Module 4 Page 1

All Rights Reserved Alcatel-Lucent 2008Issue 02

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All Rights Reserved Alcatel-Lucent 2008

Module 4Function and Features

Issue 02

Section 1Product Overview

Alcatel-Lucent GMRE+ASONOperation Rel.3.2

3FL35093AAAAZZZZZ Issue Ed02




Alcatel-Lucent GMRE+ASON Operation Rel.3.2Product Overview Function and Features1 4 2

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First editionBelgard, Steffen2006-06-0101

RemarksAuthorDateEdition

Document History





Module Objectives

Upon completion of this module, you should be able to:

Get to know what is behind ASON

Learn about Auto Discovery modes

Understand the different Restoration and Protection services

Explore Traffic Engineering technologies





Module Objectives [cont.]






Table of Contents

Switch to notes view! Page

1 ASON 71.1 Soft Permanent Connection (SPC) Service 81.2 Switched Connection (SC) Service 91.3 Bandwidth on demand 10

2 Auto Discovery 112.1 Managed mode 122.2 Full mode 132.3 Answer the questions to ASON and Auto Discovery 14

3 Protection & Restoration 153.1 Overview 163.2 Restoration Terminology 173.3 Guaranteed Restoration 193.4 Restoration Terminology SNCP 203.5 SNCP Ring Closure 213.6 Protection Restoration Combined 223.7 Reversion 233.8 Summarize Test 25

4 Traffic Engeneering 264.1 Link Bundling 274.2 Shared Risk Group Concept 284.3 Metric 294.4 Priority and Preemption 304.5 Network Fragmentation Avoidance 314.6 Summarize Test 32





Table of Contents [cont.]

Switch to notes view!






1 ASON





1 ASON

1.1 Soft Permanent Connection (SPC) Service

Client(Router)

Client(Router)

Client(Router)

IPCC

NetworkBorder Node

Drop port (GbE, SDH)

NMS

ASON

A soft permanent connection (SPC) is set by a Network Management System by accessing the head node of the path through the network.

Drop ports links to client networks are pre-provisioned by the operator.

IPCC: IP Control Channel is based on IP connectivity between two instances.

NMS: Network Management System

GbE: Gigabit Ethernet





1 ASON

1.2 Switched Connection (SC) Service

Client(Router)

Client(Router)

UNI

UNI

UNI

Client(Router)

IPCC

NetworkBorder Node

TNAASON

A switched connection (SC) is signalized by a network client to the head node which calculates a the connection through the network.

z Clients only need to have reachability information in terms of Transport Network Addresses (TNA)z Topology and resource availability is completely hidden and not visible for the clients

IPCC: IP Control Channel is based on IP connectivity between two instances.

TNA: Transport Network Address





UNI UNI

1 ASON

1.3 Bandwidth on demand

Needed Bandwidth

Client Network

ASON

Bandwidth on Demand reacts on traffic fluctuations

Client(Router)

Client(Router)

In this scenario the client requesting Bandwidth on demand decides about Restoration:

z In case of a break there is a failure notification to the head nodes, which have the knowledge about nominal and backup routes.

z The head nodes pass the failure notification via UNI to the clients.z If the client wants to use restoration, it sends back a re-dial request to the head nodes.z The head nodes are signaling to dial up a restoration path.





2 Auto Discovery





2 Auto Discovery

2.1 Managed mode

Centralized1354RMASON Manager

Q3Q3Q3

Q3

J0

J0

J0J0

J0

J0

J0

J0

J0

J0J0

J0

J0

J0

J0J0

J0 Trace identifier

Managed Mode (supported in release 4.1)

Data plane

z Data Plane is discovered by RM using the J0 bytez Trace Identifier are checked for mismatches to find miswired links. Send J0 Bytes contain local node address and local port identifier.

Received J0 Bytes indicate remote node address and remote port identifier.

z Every node must be connected to RM

Control plane

z Control plane neighbors are automatically discovered by GMRE DCC communication interfaces are automatically configured by GMRE

z Hello message exchange Allows detection of neighbor or control plane loss

Can be used for fast control plane failure detection

DCC: Data Communication Channel





2 Auto Discovery

2.2 Full mode

Only used without RM

J0

J0

J0J0

J0

J0

J0

J0

J0

J0J0

J0

J0

J0

J0J0

J0 Trace identifier LMP Messages

Full Mode

z Neighbor detection only possible without ASON Manager (supported in release 4.x)Dataplane

z Data plane automatically discovered by GMREz Operator has to accept or decline auto discovered sources and actively set them into servicez Based on J0 of the SDH Header a node can explore its directly adjacent neighbor by sending and

receiving information

Send J0 Bytes contain local node address and local port identifier.

Received J0 Bytes indicate remote node address and remote port identifier.

Control plane

z Control plane automatically discovered by GMRE DCC and OOB communication interfaces are automatically configured by GMRE

z Hello message exchange Allows detection of neighbor or control plane loss

Can be used for fast control plane failure detection

z Link Management Protocol Configuration exchange via LMP messages allows the automatic detection miswired ports.

Exchange of Traffic Engineering values

Detection of operator configuration differences (e.g. adjacent interface is down, because of maintenance)

G.7714.1/Y.1705.1 Protocol for automatic discovery in SDH and OTN networks

OOB: Out of Band (connectivity via external DCN)





2 Auto Discovery

2.3 Answer the questions to ASON and Auto Discovery

z The ASON manager is used to: Set up an SPC Set up an SC To set up every connection in an ASON

Bandwidth on Demand means: A network client signalizes the demand of bandwidth to be transported through ASON A network client can determine a route through ASON with a special bandwidth

z Auto Discovery: Finds all nodes and clients in a network Is the detection of new GMRE nodes and interfaces in a network Is a benefit from GMPLS Switches connections to the right destination

z The ASON Manager is used for: Auto Discovery in full mode Auto Discovery in managed mode





3 Protection & Restoration






3.1 Overview

z Unprotected Sub Network Connection Is not protected against failures

z Restoration mechanism: Source Based Restoration (SBR) Guaranteed Restoration (GR)

z Protection Sub Network Connection Protection (SNCP)

z Protection & Restoration Protection Restoration Combined (PRC)

E-NNI

z Due to a missing standard, external NNI connections can not be restored or protected GMRE protection.






3.2 Restoration Terminology

Client(Router)

UNI

UNI

Client(Router)

NominalBackup

Sub network connection

Nominal

z The configured route provided by the Operator/Manager or, if omitted calculated by the GMRE.z GMRE will always try to revert to this original route.

Backup

z The route provided by the Operator/Manager or, if omitted, calculated by the GMRE to be used as a backup for the nominal path when it fails.

z Until no failure exists a backup path is inactive. After switching the nominal to the backup path the backup is called active. Further more it can also have an inactive backup






3.3 Source Based Restoration

Source Based Restoration for complex failure scenarios

Client(Router)

UNI

UNI

Client(Router)

?

NominalBackup

Functionality:

z Up on a failure in the network the Source Based Restoration calculates a new routez Contention is solved by priority mechanismz The new SNC will use old route resources as much as possible

Benefit:

z SBR guarantees route recovery for any failure in the networkz Flexible and efficient use of spare network resourcesz Multiple Failure recovery without manual interventionz If other restoration mechanism (GR, PRC ) fails SBR is applied to save the traffic






3.4 Guaranteed Restoration

Guaranteed Restoration for multiple failures

Client(Router)

UNI

UNI

Client(Router)

NominalBackup (predefined)

Functionality:

z Each working SNC has a pre-reserved backup which can be shared with other backups of disjoint routesz Restoration mechanism activates the backup after failurez The backup will be restored after failure and provides fully protected status of the restored SNCz If a the backup fails, a minor error will occur.

Benefits

z Guaranteed Restoration enables SNC recovery for any failure in the networkz Flexible and efficient use of spare network resources (n+1)z Multiple failure recovery without manual interventionz Recovery of backup SNC using SBR (fallback)






3.5 Restoration Terminology SNCP

Client(Router)

UNI

UNI

Client(Router)

Main NominalSpare Nominal

Main

z With SNCP, this is the Main SNCP leg.z Can be Main-Nominal or Main-Backup (if restored using PRC)

Spare

z With SNCP, this is the Spare SNCP leg.z Can be Spare-Nominal or Spare-Backup (if restored using PRC)






3.6 SNCP Ring Closure

ADM

ADM

ADM

ADM

Single node SNCP Ring Closure (ASON external rings)In ASON network, any restoration service can be used

Main NominalSpare Nominal

Single node SNCP Ring Closure (ASON external rings)

In ASON any restoration service is applicable

z Source Based Restoration (SBR)z Guaranteed Restoration (GR)z Sub-Network Connection Protection (SNCP)z Protection Restoration Combined (PRC)






3.7 Protection Restoration Combined

Restoration for multiple failures guaranteed within 50 ms

Client(Router)

UNI

UNI

Client(Router)

MainSpareMain Backup

?

Functionality:

z SNCP is set up for highest priority paths (ultra fast recovery time)z Restoration mechanism creates a new SNCP path after failure recovery, i.e. provides fully protected

status of the restored path using SBR

Benefits

z SNCP guarantees path recovery time of less than 50 msz Flexible and efficient use of spare network resourcesz Ultra-fast multiple failure recovery without manual intervention






3.8 Reversion

Network aims to keep the configured state

Client(Router)

UNI

UNI

Client(Router)

Nominal route

Rules

z Reversion shall not preempt active traffic unless operator decides to do soz GMRE shall indicate if a reversion would preempt active trafficz Reversion can be performed automatically or manually under full operator control to avoid traffic hits

Functionality

z Reversion is done when the nominal path is available againz For Reversion, a temporary SNCP is createdz After both legs of SNCP are error-free, the SNCP is switched to the nominal pathz After both ends SNCP have switched, the SNCP is removed

Benefits

z Automated procedure to revert traffic to the original routez Usage of SNCP prevents hits during route changez Avoids network fragmentation






3.8 Reversion [cont.]

Network aims to keep the configured state

Client(Router)

UNI

UNI

Client(Router)

Nominal route

Rules

z Reversion shall not preempt active traffic unless operator decides to do soz GMRE shall indicate if a reversion would preempt active trafficz Reversion can be performed automatically or manually under full operator control to avoid traffic hits

Functionality

z Reversion is done when the nominal path is available againz For Reversion, a temporary SNCP is createdz After both legs of SNCP are error-free, the SNCP is switched to the nominal pathz After both ends SNCP have switched, the SNCP is removed

Benefits

z Automated procedure to revert traffic to the original routez Usage of SNCP prevents hits during route changez Avoids network fragmentation






3.9 Summarize Test

z What do these abbreviations mean?SBR _______________________________________GR _______________________________________PRC _______________________________________

z What is the difference between "main backup" and "spare"?____________________________________________________________________________________________________________________________________________________________________________________________________________

SNCP or Source Based Restoration: What is faster and why?____________________________________________________________________________________________________________________________________________________________________________________________________________





4 Traffic Engeneering






4.1 Link Bundling

NE BNE A

STM-1STM-4

STM-16

STM-16STM-16

STM-64

STM-1STM-4

STM-16

STM-16STM-16

STM-64

Data Bearer

Data Bearer

TE-Link #1

TE-Link #2

Specifies the STM capability as well as the local and remote

interface addresses

Specifies the TE parameters (e.g. Shared Risk Group, Link Metric) for the

Databearers,uses Databearers and can also bundle

them together

TE: Traffic Engineering

Data Plane interfaces

z Databearers: Specifies the STM capability as well as the local and remote interface addresses.

addresses (not IPv4) are derived from hardware position (rack-subrack-slot-port-channel)

z TE-Links: Specifies the TE parameters (e.g. Shared Risk Group, Link Metric) for the Databearers.

Uses Databearers and can also bundle them together (no restrictions for bundling of databearers with different STM-N levels).

Link Management provides:

z Central repository for local data linksz NE data link and TP statesz Local TE-Link states to Routingz Label related services and notifications to Signaling





z Shared Risk Group purpose: Provide a redundant route through a network

z Typical examples for SRGs are WDM links, bundled cables or cable ducts


4.2 Shared Risk Group Concept

Conduit #1

Conduit #3

Conduit #2

Conduit #4

e

cd

c Independent riskde Share the same risk

The route calculation mechanism avoids the use of links with same SRG value to be used as backup.

Example: On a failure on line 2, line 3 should not be used as an back-up.

WDM: Wavelength Division Multiplexing






4.3 Metric

UNI

UNI

Client(Router)

Nominal route

1

8

85

8

5

12

8

5

11

?

Backup with Source Based Restoration??

Backup route






4.4 Priority and Preemption

Client(Router)

UNI

UNI

Client(Router)

High priorityLow priority

Path priorities allow to support different classes of service (gold, silver, bronze, best effort, etc.)

It requires more complex preemption rules in GMRE

z Priority based preemption of backup pathsz Priority based preemption of traffic-carrying pathsz Following preemption rules are applied: Free resources shall be used whenever possible Preemption of traffic-carrying paths only if

necessary

(Nominal) routes that are set up or backup routes that are activated preempt all registered and non-active backups that cannot be accomodated any longer this is not affecting traffic!

Paths with a high priority can only preempt paths with a lower priority

Preemption of a link resource increases the link cost in CSPF depending on priority of preempted paths

GMRE provides 5 different priorities (1= highest,2,3,4,5 = lowest)






4.5 Network Fragmentation Avoidance

NE BNE A

STM-4 STM-4

Data Bearer

STM-4

STM-4 STM-4

Data Bearer

STM-4Client

AU4#1

AU4#4

Network Fragmentation Avoidence cares for the utilization of a link up to ist limit, before another one will be used. That provides:

z Lowest resource usez Reduce of Management

Note: A detailed description of Fragmentation avaoidence can be found in Section 2-1 Software Description.





z TE-Link benefits are:Higher capacityCentral Management of several linksAdding Metric and SRG to links

z What does SRG mean and provide?

z Network Fragmentation avoidenceMeans that a network can not be parted into different fragments.Links will be utilized up there full capacity, before another one is allocated.


4.6 Summarize Test





End of ModuleFunction and Features

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