Specifications

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Cisco MGX 8800/8900 Series Software Configuration Guide
Release 5.1, Part Number OL-6482-01, Rev. A0, January 25, 2005
Chapter 9 Switch Operating Procedures
Managing IMA
Enter the dspimalnks command to ensure that the correct IMA link is deleted.
Satire.2.PXM.a > dspimalnks
Link Grp Rel NE NE NE Rx Tx Rx
Num Num Dly Tx Rx Fail LID LID
(ms) State State Status
------------------------------------------------------------------------------
2.1 2.1 0 Unusable-Failed Not In Grp LIF Fail 0 255
2.2 2.1 0 Unusable-Failed Not In Grp LIF Fail 0 255
2.4 2.1 0 Unusable-Failed Not In Grp LIF Fail 0 255
Restarting an IMA Group
An IMA group must be restarted whenever a configuration or link-failure event causes the IMA group
to stop operating correctly. Figure 9-3 shows an example situation where an IMA restart may be
required.
Figure 9-3 IMA Group Restart Example
In Figure 9-3, one link in IMA Group A is operating in loopback mode, and the other three lines are
operating correctly. If different IMA group IDs are configured at each end of the IMA links (cnfimagrp
-txid), the switch can easily determine which links are in loopback and which links are connected to the
far end.
If the received far-end ID is the same as the near-end ID, the link is in loopback. If the near and far end
IDs are different, the link is communicating with the far-end IMA group.
The following situations can require an IMA restart:
1. All links are in loopback, and then individual links are connected to the remote end. In this scenario,
the IMA group is communicating with itself and must be restarted so that it will start communicating
with the far end.
2. One link is in loopback and the other links fail after successful communications have been
established with the far end. This situation creates an error condition for the IMA group which can
be cleared by restarting the IMA group and allowing the IMA group to communicate with itself over
the loopback link.
3. The failed links in situation 2 recover while the IMA group is communicating with itself. This is
really the same as situation 1. The IMA group must be restarted so that the IMA group can establish
communications with the far end.
IMA
group
A
IMA link 4
IMA
group
B
116411
IMA link 3
IMA link 2
IMA link 1
loopback