Hello,

network technician performed an ISSU upgrade on Nexus 7000 running NX-OS 5.2.4  with 1119 vlans configured and 4 VDC configured.

But immediately after the switchover occurred (30 seconds) all packets seemed to be processed by the supervisor (bpdu, hsrp, udld, ospf) that showed packet loss because of a possible CPU high utilization or hung status which affected processes requires that kind of packets for proper processing. Indeed a Spanning-Tree Dispute started to be detected on several vlans (Ports were flapping, all VLANs has been suspended from vPCs some port-channel were  down because of error-disable triggered UDLD). After 3 minutes all Spanning-Tree Dispute cleared. We found the bug id CSCui49735 that perfectly describes this behavior. This bug is found on 6.2(2)S28. Did someone found this issue on previous version that 6.2(2)S28?

thank you

Germana AT&T