Ethernet Remote Defect Indication; Asi And Rdi Configuration Guidelines And Restrictions - Cisco WS-C6506 Software Manual

Configuring the Alarm Indication Signal
A Server MEP represents both the server layer termination function and Server/Ethernet adaptation
Note
function. In the Cisco IOS software, the Link OAM and Interface/Line Protocol state act as Server MEPs.
Timer Spread Design Logic and Guidelines:
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Ethernet Remote Defect Indication

A MEP uses an ETH-RDI to communicate to its peer MEPs that a defect condition has occurred. A MEP
uses an ETH-RDI only when an Ethernet Continuity-Check transmission is enabled.
A MEP that is in a defect condition transmits frames with the ETH-RDI information. When a MEP
receives frames with ETH-RDI information, it determines that its peer MEP has encountered a defect
condition. However, in a multipoint Ethernet connection, when a MEP receives frames with ETH-RDI
information, it cannot determine which peer MEP has a fault condition.
The Ethernet Remote Defect Indication has two management applications:
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2.

ASI and RDI Configuration Guidelines and Restrictions

When configuring ASI and RDI, follow these configuration guidelines and restrictions:
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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
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The AIS transmission interval has been hard coded to 1 second and it can be changed to1 minute
dynamically, after the configured number of AIS PDUs are transmitted (default 5).
The AIS timer logic is designed such that depending upon the global AIS PDU transmission count
configured on the switch, you can determine the number of AIS PDUs which will be sent at 1 second
interval periodically, when the link failure is detected by the server MEP. The default AIS packet
count is set to 5.
When the defect condition is cleared, the Server MEP sends another set of AIS PDUs (global AIS
PDU tx_count configured on the switch) with 1 second interval. So, that the subsequent remote
MEPs comes out of the AIS defect condition faster.
Both the Server MEP and the Local MEP follows the same timer logic to transmit the AIS further
in the network.
Single-ended fault management—The receiving MEP detects an RDI, which indicates that some of
its remote MEPs have failed. When an RDI is not present, it indicates the absence of defects in all
the MEPs in a network. This RDI mechanism helps the administrator in the fault management
activity on a per service basis.
Contribution to far-end performance monitoring—An ETH-RDI indicates that there was a defect
condition in the far end of a network. This information is used as an input to the performance
monitoring process.
You must enable CFM and AIS globally on a switch.
You must enable CFM on the port before you enable AIS.
You must enable the Link-OAM on the Server MEP port so that the Link OAM-CFM can function.
If you explicitly disable CFM globally but the AIS remains enabled, the AIS configuration displays
in the configuration. However, the AIS is not functional.
Chapter 20 Checking Status and Connectivity
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