HIGHRESOLVEDCISCOOSPFIOS-XEUpgrade

OSPF Adjacency Failure after IOS-XE 17.9.3 Upgrade

OSPF adjacencies dropped on all P2P links post-upgrade. EXSTART/EXCHANGE loop observed.

Ngozi Adeyemi

CISCO CCNP #88712· Airtel Nigeria· Jun 5, 2026

Problem

OSPF adjacencies dropped on all P2P links post-upgrade. EXSTART/EXCHANGE loop observed.

Compared config diff before/after. Checked timer values. Tested with debug ip ospf adj.

Explicitly set hello/dead timers back to 10/40s on all P2P interfaces. Cleared OSPF process.

IOS-XE 17.9.3 changed P2P interface default timers to 3/12s without documentation.

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