Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010, Configuration Manual

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Reverting After a Failover
When you specify the auto-revert keyword with the redundant-port command, the
redundant link reverts back to redundant mode when the failed link becomes active
again.
The system uses the following processes when the auto-revert feature is enabled (by
specifying the
auto-revert keyword) or disabled.
When auto-revert is enabled:
1.
An active link fails and a redundant link becomes active.
2.
The original active link becomes active.
3.
The original redundant link fails over to the original active link.
4.
The redundant link can fail over to any other active link again.
When auto-revert is disabled:
1.
An active link fails and a redundant link becomes active.
2.
The original active link becomes active.
3.
The original redundant link remains the active link.
4.
You can force the link to fail over by issuing the redundant-port force-failover
command.
LACP Configuration and Member Link Behavior
By default, when a redundant member link is configured, the system disables LACP
and the transmitter on that link.
When a member link is administratively down, the link state is operationally down
at the local and remote ends, which means it does not transmit or receive PDUs.
The active link does not fail over when:
■
An active link goes down and you set the redundant member link to
administratively down.
■
An active link is set to administratively down.
LACP configurations affect member link behavior based on the local or remote
endpoint. For a remote end to include a member link in link aggregation, the two
member links that are connected must have LACP configured.
Table 10 on page 218 lists the acceptable configurations that enable redundant behavior
for LACP modes at local and remote endpoints.
Ethernet Link Redundancy Behavior
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Chapter 6: Configuring 802.3ad Link Aggregation and Link Redundancy