Preview Tool

Cisco Bug: CSCvv42889 - SVI up/down event causes outage with L2 multicast

Last Modified

Sep 25, 2020

Products (1)

  • Cisco Nexus 9000 Series Switches

Known Affected Releases


Description (partial)

During SVI up/down event, there is disruption to multicast flow due to two symptoms:

1. IGMP snooping groups are getting cleared together with IGMP groups.

2. IGMP general queries from uplink interfaces being ignored for ~20 seconds after the SVI up/down event. Considering that IGMP queries are being sent out relatively rarely and all initial queries (configured with startup-query-interval and startup-query-count) are dropped, it leads to issues with re-building control plane state for L2 forwarding.
Approximately after 20-25 seconds, IGMP general queries start to get processed and group table for IGMP snooping is re-built.

Up/down event for SVI
Bug details contain sensitive information and therefore require a account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.