Catalyst 4500 Series Switch Software Configuration Guide, 12.2(46)SG
Configuring Y.1731
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Configuring Y.1731 (AIS and RDI)

Table Of Contents

Configuring Y.1731 (AIS and RDI)

Definition List

Y.1731 Overview

Background

Server MEP

Alarm Indication Signal

Ethernet Remote Defect Indication

Configuring Y.1731

Y.1731 Configuration Guideline

Configuring AIS Parameters

Clearing MEP from the AIS defect condition

Clearing SMEP from the AIS defect condition

Displaying Y.1731 Information


Configuring Y.1731 (AIS and RDI)


The Catalyst 4500 series switch supports Y.1731 Ethernet Alarm Indication Signal function (ETH-AIS) and Ethernet Remote Defect Indication function (ETH-RDI) to provide fault and performance management for service providers in large networks. This chapter describes how to configure Y.1731 ETH-AIS and ETH-RDI.


Note For complete command and configuration information for Y.1731, see the Cisco IOS feature module at this URL:

http://www.cisco.com/en/US/docs/ios-xml/ios/cether/configuration/12-2sr/ce-cfm-y1731.html


This chapter contains these sections:

Definition List

Y.1731 Overview

Configuring Y.1731

Displaying Y.1731 Information

Definition List

Term
Definition

CC

Ethernet OAM Continuity Check

CCM

Ethernet OAM Continuity Check Message

CCDB

Ethernet OAM Continuity Check Database

CFM

Ethernet Connectivity Fault Management

EI

Ethernet Infrastructure or EVC Infrastructure

EVC

Ethernet Virtual Circuit

LMEP

Local Mep

MEP

Maintenance Endpoint

MIP

Maintenance Intermediate Point

OAM

Operations Administration and Maintenance

Service VLAN

The VLAN tag that uniquely identifies a Customer Service Instance within the Provider network

SMEP

Server Mep

SNMP

Simple Network Management Protocol

SP

Service Provider

UNI

User to Network Interface

VLAN

Virtual LAN


Y.1731 Overview

These sections contain conceptual information about Y.1731:

Background

Alarm Indication Signal

Ethernet Remote Defect Indication

Background

The advent of Ethernet as a metropolitan and WAN technology imposes a new set of Operations, Administration and Maintenance (OAM) requirements on Ethernet's traditionally Enterprise-oriented functions. The expansion of this technology into the larger and more complex wider user base makes operational management of link uptime crucial. Isolating and responding to failures quickly directly affects the competitiveness of the Service Provider.

Server MEP

A Server MEP represents the compound function of the Server layer termination and Server/ETH adaptation function that is used to notify the ETH layer MEPs upon failure detection by the Server layer termination function or Server/ETH adaptation function, where the Server layer termination function is expected to run OAM mechanisms specific to the Server layer. A Server MEP needs to support ETH-AIS function and the Server/ETH adaptation function is required to issue frames with ETH-AIS information upon detection of a defect at the Server layer by the Server layer termination and/or adaptation function.

A virtual MEP represents the logical termination point of CFM MAs defined at the link or transport layer. You might imagine a server MEP as one running or defined at Maintenance Level -1. For example, you could associate an outward facing Server MEP with each termination point of IEEE 802.3ah OAM, or with each termination point of MPLS PW OAM.

Alarm Indication Signal

ETH-AIS enables you to suppress alarms following detection of defect conditions at the server (sub) layer. Due to independent restoration capabilities provided within the Spanning Tree Protocol (STP) environments, you would not expect to apply ETH-AIS in the STP environments. For the Catalyst 4500 Metro switch, AIS is configurable; the administrator can enable and disable AIS in the STP environment.

Transmission of frames with ETH-AIS information can be enabled or disabled on a MEP (or on a Server MEP).

Frames with ETH-AIS information can be issued at the client Maintenance Level by a MEP, including a Server MEP upon detecting defect conditions. For example, the defect conditions may include:

Signal fail conditions in the case that ETH-CC is enabled

AIS condition in the case that ETH-CC is disabled

For multipoint ETH connectivity, a MEP cannot determine the specific server (sub) layer entity that has encountered defect conditions upon receiving a frame with ETH-AIS information. More importantly, it cannot determine the associated subset of its peer MEPs for which it should suppress alarms since the received ETH-AIS information does not contain that information. Therefore, upon reception of a frame with ETH-AIS information, the MEP suppresses alarms for all peer MEPs whether there is still connectivity or not.

For a point-to-point ETH connection, however, a MEP has only a single peer MEP. Therefore, there is no ambiguity regarding the peer MEP for which it should suppress alarms when it receives the ETH-AIS information.

Only a MEP, including a Server MEP, is configured to issue frames with ETH-AIS information. Upon detecting a defect condition the MEP can immediately start transmitting periodic frames with ETH-AIS information at a configured client Maintenance Level. In Cisco IOS we send at MIP level configured at the interface. A MEP continues to transmit periodic frames with ETH-AIS information until the defect condition is removed. Upon receiving a frame with ETH-AIS information a MEP detects AIS condition and suppresses loss of continuity alarms associated with all its peer MEPs. A MEP resumes loss of continuity alarm generation upon detecting loss of continuity defect conditions in the absence of AIS condition.

Ethernet Remote Defect Indication

A MEP can use ETH-RDI to communicate to its peer MEPs that a defect condition has been encountered. ETH-RDI is used only when ETH-CC transmission is enabled.

ETH-RDI has the following two applications:

Single-ended fault management: The receiving MEP detects an RDI defect condition, which gets correlated with other defect conditions in this MEP and may become a fault cause. The absence of received ETH-RDI information in a single MEP indicates the absence of defects in the entire Maintenance.

Contribution to far-end performance monitoring: It reflects that there was a defect condition in the far-end which is used as an input to the performance monitoring process.

A MEP that is in a defect condition transmits frames with ETH-RDI information. A MEP, upon receiving frames with ETH-RDI information, determines that its peer MEP has encountered a defect condition. For multipoint ETH connectivity, however, a MEP, upon receiving frames with ETH-RDI information, cannot determine the associated subset of its peer MEPs with which the MEP transmitting RDI information encounters defect conditions. This is because the transmitting MEP itself does not always have that information.

Figure 57-1 Generation and Propagation of AIS Messages and the CC with RDI upon a Defect (link fail)I

Configuring Y.1731


Note Y.1731 is enabled by default.


These sections are included

Y.1731 Configuration Guideline

Configuring AIS Parameters

Clearing MEP from the AIS defect condition

Clearing SMEP from the AIS defect condition

Y.1731 Configuration Guideline

Configuration guidelines and restrictions for Y.1731 include the following:

ETH-AIS is not expected to be applied in the STP environments, because of independent restoration capabilities provided within the STP.

AIS is enabled by default on an CFM maintenance domain. The following section illustrates the commands you can use to disable AIS on a maintenance domain. Like-wise, RDI is a flag bit in the CC message. Provided CC transmission is enabled, the present RDI flag of the CC message is set to true or false.

Configuring AIS Parameters

To set the parameters for AIS, do the following:

 
Command
Purpose

Step 1 

Switch# configure terminal

Enters global configuration mode.

Step 2 

Switch (config)# ethernet cfm ais domain name vlan range

Enters config-ais-mep-cfm submode to configure parameters for all local mep belonging to that per MA.

name refers to the domain name

range is "VLAN IDs e.g. 100 or 1-4095 or 100,200-300,400,500"

For domain vlan rang only configurations that are VLAN disjoint or congruent are accepted.

Step 3 

Switch(config-ais-mep-cfm)# disable

Disables AIS transmission.

Step 4 

Switch(config-ais-mep-cfm)# period period

Sets the AIS transmission period.

Step 5 

Switch(config-ais-mep-cfm)# level level

Establishes a maintenance level to send AIS frames for MEPs belonging to MA.

Valid levels are 0 thru 7.

Step 6 

Switch(config-ais-mep-cfm)# expiry-threshold threshold

Sets the AIS Expiry threshold.

By default expiry threshold is 3.5. With this CLI we can change the expiry threshold parameter for MA.

Step 7 

Switch(config-ais-mep-cfm)# express alarm

Configures the suppression of alarms when MEP enters an AIS defect condition due to an AIS message.

Step 8 

Switch(config-ais-mep-cfm)# exit

Returns to global configuration.

Step 9 

Switch(config)# [no] ethernet cfm ais
link-status global

Enters config-ais-link-cfm submode to configure parameters required to follow when link status goes down as reported by E-OAM.

Step 10 

Switch(config-if)# [no] ethernet cfm ais link-status period period

Configures ETH-AIS transmission period generated by the link-status on the interface.

Step 11 

Switch(config-if)# [no] ethernet cfm ais link-status level level

Configures maintenance level to send AIS frames transmitted by the link-status on the interface.

Step 12 

end

Returns to privileged EXEC mode.

Step 13 

Switch# show ethernet cfm smep interface name

Switch# show ethernet cfm maintenance-points local detail

Switch# show ethernet cfm maintenance-points remote detail

Switch# show ethernet cfm error

Verifies the configuration.

Step 14 

Switch# show running-config

Verify your entries.

Step 15 

Switch# copy running-config startup-config

(Optional) Saves your entries in the configuration file.

Use the no versions of the commands to remove the configuration or return to the default configurations.

Clearing MEP from the AIS defect condition

To do this, use one of the following commands:

Switch# clear ethernet cfm ais domain domain name mpid local mpid vlan vlan#
Switch# clear ethernet cfm ais domain domain name mpid local mpid evc evc_name

Clearing SMEP from the AIS defect condition

To do this, use one of the following commands:

Switch# clear ethernet cfm ais link-status interface interface_name
Switch# clear ethernet cfm error

Note This also clears all error conditions including AIS.


Displaying Y.1731 Information

This example show how to track the RDI defect and to verify the configuration parameters:

Switch# show ethernet cfm main local detail
MEP Settings:
-------------
MPID: 1109
DomainName: PROVIDER_DOMAIN
Level: 4
Direction: I
EVC: evc_1
Interface: Gi3/1
CC-Status: Enabled
MAC: 001b.d550.91fd
Defect Condition: No Defect
presentRDI: FALSE (RDI defect is NOT present)
AIS-Status: Enabled
AIS Period: 60000(ms)
AIS Expiry Threshold: 3.5
Level to transmit AIS: Default
Suppress Alarm configuration: Enabled
Suppressing Alarms: No
 
   
MIP Settings:
-------------
Level Type  Port                      MAC
7     MIP   Gi3/1                     001b.d550.91fd
4     MIP   Te1/2                     001b.d550.91fd
Switch#
*Feb 18 05:40:35.659: %ETHER_CFM-6-ENTER_AIS: local mep with mpid 1109 level 4 id 100 dir 
I Interface GigabitEthernet3/1 enters AIS defect condition  
(gi3/2 enters AIS state)
Switch# show ethernet cfm main local detail
MEP Settings:
-------------
MPID: 1109
DomainName: PROVIDER_DOMAIN
Level: 4
Direction: I
EVC: evc_1
Interface: Gi3/1
CC-Status: Enabled
MAC: 001b.d550.91fd
Defect Condition: AIS
presentRDI: TRUE (RDI defect IS present)
AIS-Status: Enabled
AIS Period: 60000(ms)
AIS Expiry Threshold: 3.5
Level to transmit AIS: Default
Suppress Alarm configuration: Enabled
Suppressing Alarms: Yes
 
   
MIP Settings:
-------------
Level Type  Port                      MAC
7     MIP   Gi3/1                     001b.d550.91fd
4     MIP   Te1/2                     001b.d550.91fd
Switch# show ethernet cfm error
Level Vlan MPID Remote MAC     Reason               Service ID
4     100  2101 001d.4566.aa3d 0 lifetime TLV       customerX
4     100    -  001b.d550.91fd Receive AIS          customerX
Switch#
*Feb 18 05:51:08.567: %ETHER_CFM-6-EXIT_AIS: local mep with mpid 1109 level 4 id 100 dir I 
Interface GigabitEthernet3/1 exited AIS defect condition
(gi3/1 exits AIS state)
Switch# show ethernet cfm main local detail
MEP Settings:
-------------
MPID: 1109
DomainName: PROVIDER_DOMAIN
Level: 4
Direction: I
EVC: evc_1
Interface: Gi3/1
CC-Status: Enabled
MAC: 001b.d550.91fd
Defect Condition: No Defect
presentRDI: FALSE (RDI defect is not present anymore)
AIS-Status: Enabled
AIS Period: 60000(ms)
AIS Expiry Threshold: 3.5
Level to transmit AIS: Default
Suppress Alarm configuration: Enabled
Suppressing Alarms: No
 
   
MIP Settings:
-------------
Level Type  Port                      MAC
7     MIP   Gi3/1                     001b.d550.91fd
4     MIP   Te1/2                     001b.d550.91fd
Switch#
 
   

To display Y.1731 information, you can use the following commands (Table 57-1).

Table 57-1 Displaying Y.1731 Information  

Command
Purpose
show ethernet cfm maintenance-point local 
detail

Displays AIS Status and Defect Condition on Local Maintenance Points

show ethernet cfm smep [interface <name>]

Displays AIS Status and Defect Condition on SMEP

show ethernet cfm error

Displays Errors due to AIS Defect Condition

show ethernet cfm maintenance-points 
remote [detail

Displays AIS Status and Defect Condition on Remote Maintenance Points