Symptom
- BGP Multi path PIC ECMP auto protection feature was introduced and implemented as default behaviour in 7.5.2.
- When there is an upgrade from any version below 7.5.2 to any version on or above 7.5.2, ECMP FEC NPU resource exhaustion is seen on BGP peering devices for IPv4/IPv6 as auto protection is enabled by default.
- To avoid running into ECMP FEC resource exhaustion, BGP Multi path PIC ECMP auto protection behaviour is disabled by default in 7.5.4, 7.8.2 and 7.9.1 and above.
- To enable auto-protection, "hw-module fib bgp-mp-pic auto-protect enable" must be configured in these releases.
Conditions
This issue will be seen on XR devices with heavy BGP peering and multiple next-hop to same destination (ECMP).
Further Problem Description
This issue leads to ECMP FEC resource exhaustion.
NOTE:
BGP Multi path PIC ECMP auto protection feature is now disabled by default in 7.5.4, 7.8.2 and 7.9.1 and versions above. In other releases, BGP Multi path PIC ECMP auto protection feature will be enabled by default.
