Alcatel-Lucent 7210 SAS M Interface Configuration Manual page 41

1. If the number of links available (up) in a LAG is less than the configured threshold, then
2. When the number of links available in a LAG is less than the configured threshold, the
7210 SAS M, T, X, R6, R12, Mxp Interface Configuration Guide
LAG port threshold value. If the number of available links falls below the configured
threshold, the configured threshold action determines if and at what cost this LAG
will be advertised.
For example, assume a single link in OSPF has an associated cost of 100 and the LAG
consists of four physical links. The cost associated with the logical link is 25. If one
link fails then the cost would automatically be adjusted to 33.
If dynamic cost is not configured then costing is applied based on the total number of
links configured. The cost would be calculated at 25. This will remain static provided
the number of links that are up exceeds the configured LAG threshold.
→ LAG port threshold
The LAG port threshold feature allows configuration of the behavior, once the
number of available links in a LAG falls below or is equal to the specified threshold.
Two options are available:
the LAG is regarded as operationally down.
For example, assume a LAG consists of four physical links. The threshold is set to two
and dynamic costing is not configured. If the operational links is equal to or drops below
two, the link is regarded as operationally down until the number of operational links is
two or more.
LAG starts using the dynamic-cost allowing other nodes to adjust their routing tables
according to the revised costs. In this case, when the threshold is not crossed, a fixed
metric (all links operational) is advertised.
Interface Configuration
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