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Cisco Bug: CSCus13479 - 4500X VSS: multicast traffic blackholed on orphan L3 egress portchannel

Last Modified

Sep 14, 2018

Products (1)

  • Cisco Catalyst 4500 Series Switches

Known Affected Releases

3.6(0) 3.7(0)

Description (partial)

Symptom:
4500X VSS multicast traffic blackholed on orphan L3 egress portchannel. During problem symptom, traffic hits L2 floodset entry even though L3 entry si present and get dropped.There is a mismatch seen in state of ipv4MulticastEn between active and standby when switch is in this state. 

hrn3-4500x-vss-01#sh platfo hardware rxvlan-map-table  vl 200  <<< Ingress port

Executing the command on VSS member switch role = VSS Active, id = 1


Vlan 200:
l2LookupId:           200
srcMissIgnored:       0
ipv4UnicastEn:          1
ipv4MulticastEn:        1  <<<<<
ipv6UnicastEn:          0
ipv6MulticastEn:        0
mplsUnicastEn:          0
mplsMulticastEn:        0
privateVlanMode:      Normal
ipv4UcastRpfMode:     None
ipv6UcastRpfMode:     None
routingTableId:       1
rpSet:                0
flcIpLookupKeyType:   IpForUcastAndMcast
flcOtherL3LookupKeyTypeIndex: 0
vlanFlcKeyCtrlTableIndex:     0
vlanFlcCtrl:                  0


Executing the command on VSS member switch role = VSS Standby, id = 2


Vlan 200:
l2LookupId:           200
srcMissIgnored:       0
ipv4UnicastEn:          1
ipv4MulticastEn:        0   <<<<<
ipv6UnicastEn:          0
ipv6MulticastEn:        0
mplsUnicastEn:          0
mplsMulticastEn:        0
privateVlanMode:      Normal
ipv4UcastRpfMode:     None
ipv6UcastRpfMode:     None
routingTableId:       1
rpSet:                0
flcIpLookupKeyType:   IpForUcastAndMcast
flcOtherL3LookupKeyTypeIndex: 0
vlanFlcKeyCtrlTableIndex:     0
vlanFlcCtrl:                  0

Conditions:
NA
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