Cisco Nexus 1000V Troubleshooting Manual page 191

Chapter 18 Multicast IGMP
S e n d d o c u m e n t c o m m e n t s t o n e x u s 1 k - d o c f e e d b a c k @ c i s c o . c o m .
Device ID
n1000V
n1000V
show ip igmp groups
•
Use the show ip igmp groups command to make sure IGMP snooping is enabled on the VLAN.
Example 18-2 show ip igmp snooping vlan Command
n1000V# show ip igmp snooping vlan 159
IGMP Snooping information for vlan 159
show ip igmp snooping groups
•
debug ip igmp snooping vlan
•
Example 18-3 debug ip igmp snooping vlan Command
n1000V(config)# debug ip igmp snooping vlan
2008 Sep
2008 Sep
224.0.0.251 fro 7.159.159.54 on Vethernet3
2008 Sep
224.0.0.251) entry
2008 Sep
224.0.0.251) came on Vethernet3
2008 Sep
router-ports
2008 Sep
Ethernet3/6 (iod 42)
On the VSM, use the following command:
module vem module-number execute vemcmd show vlan
•
In
VM fedora8, interface eth0.
The multicast group table for 224.1.2.3, shows the interfaces the VEM will forward to when it
receives multicast traffic for group 224.1.2.3. If fedora8 has multicast group 224.1.2.3 on its eth0
interface, then LTL 47 should be in the multicast group table for 224.1.2.3.
LTL 18 is also in multicast group 224.1.2.3, which means it is a VM and generates multicast traffic
to 224.1.2.3. The traffic will be forwarded to vmnic3, which is the uplink to the upstream switch.
The multicast group table entry for 0.0.0.0 serves as a default route. If any multicast group traffic
does not match any of the multilcast group, the address will use the default route, which means, in
this case, that the traffic will be forwarded to an upstream switch through vmnic3.
OL-28795-01
S - Switch, H - Host, I - IGMP, r - Repeater,
V - VoIP-Phone, D - Remotely-Managed-Device,
s - Supports-STP-Dispute
Local Intrfce
Eth3/2
Eth3/4
IGMP snooping enabled
IGMP querier none
Switch-querier disabled
IGMPv3 Explicit tracking enabled (initializing, time-left: 00:03:20)
IGMPv2 Fast leave disabled
IGMPv1/v2 Report suppression enabled
IGMPv3 Report suppression disabled
Router port detection using PIM Hellos, IGMP Queries
Number of router-ports: 0
Number of groups: 0show ip igmp snooping
2 13:29:36.125661 igmp: SNOOP: <vlan 159> Process a valid IGMP packet
2 13:29:36.126005 igmp: SNOOP: <vlan 159> Received v2 report: group
2 13:29:36.126086 igmp: SNOOP: <vlan 159> Added oif Vethernet3 for (*,
2 13:29:36.126157 igmp: SNOOP: <vlan 159> Forwarding report for (*,
2 13:29:36.126225 igmp: SNOOP: <vlan 159> Forwarding the packet to
2 13:29:36.126323 igmp: SNOOP: <vlan 159> Forwarding packet to router-port
Example 18-4, the output shows that LTL 18 corresponds to vmnic3, and LTL 47 corresponds to
Hldtme Capability
179 R S I WS-C6506-E
179 R S I WS-C6506-E
<-- IGMP SNOOPING is enabled for vlan 159
Cisco Nexus 1000V Troubleshooting Guide, Release 4.2(1)SV2(2.1)
Problems with Multicast IGMP Snooping
Platform Port ID
Gig5/16
Gig5/23
18-3