Details techniques for avoiding IS-IS overload conditions, including configuration methods and operational strategies to ensure network stability and minimize routing disruptions.
IS-IS overload bit avoidance feature is a routing protocol enhancement that
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allows continued use of label switched paths (LSPs) even if routers within the path are flagged with the IS-IS overload bit,
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enables administrators to ignore overload bit status for head, mid, and tail nodes during path selection, and
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provides command-line control for activation and deactivation, ensuring flexibility in traffic engineering.
| Feature Name |
Release Information |
Feature Description |
|---|---|---|
| IS-IS Overload Bit Avoidance |
Release 25.4.1 |
Introduced in this release on: Fixed Systems (8700 [ASIC: K100])(select variants only*) *This feature is supported on Cisco 8711-48Z-M routers. |
| IS-IS Overload Bit Avoidance |
Release 7.0.1 |
You can keep label switched paths (LSPs) available, even if some routers in the path have their IS-IS overload bit set. This feature prevents unnecessary LSP disablement. When you activate this feature, routers with the overload bit set, whether they are head, mid, or tail nodes, are still considered for LSPs. To enable this feature, use the mpls traffic-eng path-selection ignore overload command. If you disable the feature, the system uses the default behavior and excludes these nodes from LSPs except as nodes of last resort. |
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When you activate overload bit avoidance, label switched paths remain available even if routers in the path have their overload bit set. This prevents unnecessary disablement of paths.
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If you deactivate overload bit avoidance, routers with the overload bit set cannot be used as nodes of last resort, which may cause LSPs to be disabled.
The IS-IS overload bit avoidance feature does not change the default behavior on nodes with their overload bit set if those nodes are not included in the path calculation.