Cisco Nexus 1000V User Manual

19-2
Cisco Nexus 1000V Troubleshooting Guide, Release 5.2(1)SV3(1.1)
OL-31593-01
Chapter 19 Multicast IGMP
Problems with Multicast IGMP Snooping
Problems with Multicast IGMP Snooping
The operation of multicast IGMP snooping depends on the correct configuration of the upstream switch.
Because the IGMP process needs to know which upstream port connects to the router that supports IGMP
routing, you must turn on IP multicast routing on the upstream switch by entering the
ip multicast-routing command.
The following example shows how to turn on global multicast routing, configure an SVI interface, and
turn on the PIM routing protocol:
switch# conf terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# ip multicast-routing
switch(config)# end
switch# conf terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# int vlan159
switch(config-if)# ip pim dense-mode
switch(config-if)# end
The following example shows a sample Cisco Nexus 5000 Series configuration that has an IGMP querier
configured on a VLAN:
n5k-sw1(config)# vlan configuration 59
n5k-sw1(config-vlan-config)# ip igmp snooping querier 7.59.59.1
n5k-sw1(config-vlan-config)# ip igmp snooping query-interval 60
n5k-sw1(config-vlan-config)# ip igmp snooping version 3
n5k-sw1(config-vlan-config)#
Troubleshooting Guidelines
Follow these guidelines when troubleshooting multicast IGMP issues:
• Use the show ip igmp snooping command to verify that IGMP snooping is enabled.
• Make sure that the upstream switch has IGMP configured.
• Use the show ip igmp snooping groups command to verify if the Cisco Nexus 1000V switch is
configured correctly and is ready to forward multicast traffic. In the displayed output of the
command, look for the letter R under the port heading. The R indicates that the Virtual Supervisor
Module (VSM) has learned the uplink router port from the IGMP query that was sent by the
upstream switch, and means that the Cisco Nexus 1000V is ready to forward multicast traffic.
IGMP Snooping Debugging Commands
You can enable debugging commands for IGMP snooping:
Step 1 Enable logs files on the module that hosts the preferred VMs/Veths.
switch(config)# module vem 4 execute vemdpalog debug sfigmp_snoop d
switch(config)# module vem 4 execute vemlog debug sfigmp_snoop d
Step 2 (Optional) Clear existing log data.
switch(config)# module vem 4 execute vemlog clear
Cleared log

Cisco Nexus 1000V Specifications

General

Type	Virtual Switch
Manageable	Yes
NetFlow	Yes
SPAN	Yes
ERSPAN	Yes
Operating System	Cisco NX-OS
Form Factor	Virtual
Hypervisor Support	VMware ESXi
Features	VXLAN
Security Features	Port Security, Private VLANs, ACLs