Cisco Bug: CSCvj14441 - PTP GM clock sync loss after switchover
Aug 19, 2018
- Cisco Nexus 7000 Series Switches
Known Affected Releases
Symptom: Nexus 7000 running 8.2(1) with N77-M348XP-23L and N77-SUP2E linecards. PTP stops working after a switchover takes place. Issue was narrowed down to a lack of PTP multicast address Membership reports from Nexus 7000 after a Switchover takes place. Due to this lack of Membership reports, PTP announcements from GM clock are no longer received via the layer 2 switch sitting in between, hence the Nexus stops seeing the GM clock and claim itself as the new GM clock. Conditions: -PTP enable on l3 port on N77-M348XP-23L linecard -Layer 2 switch sits in between GM clock and Nexus -Layer 2 switch in between has an IGMP group for reserved address 126.96.36.199 -Port connecting to GM clock and Nexus show up as interested parties. -Switchover takes place and Nexus 7000 stops responding to general queries and does not joing any more 188.8.131.52. -Eventually layer 2 switch in between stops forwarding traffic to Nexus, so PTP announcements from GM clock are no longer seen. -N7k will clain itself as the new GM clock.
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