Cisco Bug: CSCvv20275 - UFI : ECMP FEC being used for DH multi homing PIC prefix on core bundle shut
Oct 09, 2020
- Cisco ASR 9000 Series Aggregation Services Routers
Known Affected Releases
Release-note Symptom: This error may be seen, LC/0/0/CPU0:Jul 29 10:47:12.023 PDT: fib_mgr: %PLATFORM-PLAT_FIB-4-OOR_PROT_START_WARNING : Request for ECMP_FEC exceeded the maximum allowed. OOR protection started Conditions: 1 - Large number of BGP prefixes (32K), in per-prefix label mode 2 - The BGP prefixes have protection, ie, backup paths. However, the same underlying BGP LU is shared. 3 - The BGP paths are BGP LU (collapsed mode), and also protected. Primary and backup use their own separate interfaces. When the core interface is shut, unexpected events happened. A - Received FRR interface down event from PFI infra, which triggers switch over to use backup interface at BGP LU level B - Both interfaces stay up. This is not consistent with the interface down event from PFI C - Adjacency routes got deleted for both interfaces D - primary LSD attached route is not deleted, but the backup LSD attached route is deleted The above sequence caused miscalculation at BGP PIC. Thus primary, and backup paths become ECMP.
Bug details contain sensitive information and therefore require a Cisco.com account to be viewed.
Bug Details Include
- Full Description (including symptoms, conditions and workarounds)
- Known Fixed Releases
- Related Community Discussions
- Number of Related Support Cases