LevelOne GTL-2691 User Manual

Page 495

HAPTER

| Basic Administration Protocols

Connectivity Fault Management

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LTMs are sent as multicast CFM frames, and forwarded from MIP to MIP,

with each MIP generating a link trace reply, up to the point at which the

LTM reaches its destination or can no longer be forwarded.

◆

LTMs are used to isolate faults. However, this task can be difficult in an

Ethernet environment, since each node is connected through multipoint

links. Fault isolation is even more challenging since the MAC address of

the target node can age out in several minutes. This can cause the

traced path to vary over time, or connectivity lost if faults cause the

target MEP to be isolated from other MEPs in an MA.

◆

When using the command line or web interface, the source MEP used

by to send a link trace message is chosen by the CFM protocol.
However, when using SNMP, the source MEP can be specified by the

user.

◆

Parameters controlling the link trace cache, including operational state,

entry hold time, and maximum size can be configured on the Configure

Global page (see

"Configuring Global Settings for CFM"

ARAMETERS

These parameters are displayed:

◆

MD Index – Domain index. (Range: 1-65535)

◆

MA Index – MA identifier. (Range: 0-4094)

◆

Source MEP ID – The identifier of a source MEP that will send the link

trace message. (Range: 1-8191)

◆

Target

■

MEP ID – The identifier of a remote MEP that is the target of a link

trace message. (Range: 1-8191)

■

MAC Address – MAC address of a remote MEP that is the target of

a link trace message. This address can be entered in either of the

following formats: xx-xx-xx-xx-xx-xx or xxxxxxxxxxxx

◆

TTL – The time to live of the link trace message. (Range: 0-255 hops)

NTERFACE

To transmit link trace messages:

Click Administration, CFM.

Select Transmit Link Trace from the Step list.

Select an entry from MD Index and MA Index.

Specify the source MEP, the target MEP using either its MEP identifier or
MAC address, and set the maximum number of hops allowed in the TTL

field.