Cisco Bug: CSCvu12905 - Cat6k - Sup2T - DHCPv6 control packets snooped by MLD when forwarded over VPLS circuit
Sep 01, 2020
- Cisco Catalyst 6000 Series Switches
Known Affected Releases
Symptom: DHCPv6 control packets (whose IPv6 destination is the multicast address FF02::1:2) are snooped by MLD Snooping when forwarded over a VPLS circuit. These packets shouldn't be snooped as they are control packets and not regular multicast traffic. Since the Sup2T is incorrectly snooping these packets, then they won't be forwarded over the VPLS circuit and will be silently dropped by the platform, unless the VPLS circuit is an mrouter port for the VLAN that is extended over the circuit. Conditions: - VPLS is configured on the Sup2T to extend the VLAN where DHCPv6 is being used. - DHCPv6 messages need to traverse the VPLS circuit (i.e. if the DHCPv6 Server resides on the other end of the VPLS circuit). - MLD Snooping is enabled on that same VLAN.
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Bug Details Include
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