IGMP Snooping Over VXLAN

Overview of IGMP Snooping Over VXLAN

The configuration of IGMP snooping is same in VXLAN as in configuration of IGMP snooping in regular VLAN domain. All the configuration CLIs remain the same. For more information on IGMP snooping, see the Configuring IGMP Snooping section in Cisco Nexus 3000 Series NX-OS Multicast Routing Configuration Guide.

Guidelines and Limitations for IGMP Snooping Over VXLAN

See the following guidelines and limitations for IGMP snooping over VXLAN:

  • IGMP snooping over VXLAN is supported.

  • IGMP snooping on VXLAN VLAN is disabled by default.

  • For IGMP snooping over VXLAN, all the guidelines and limitations of VXLAN apply.

  • IGMP snooping over VXLAN is not supported on any FEX enabled platforms and FEX ports.

  • IGMP snooping over VXLAN VLAN is supported for Cisco Nexus 3100-V and 3172 platform switches in N9K mode only.

Configuring IGMP Snooping Over VXLAN

Before you begin

For VXLAN IGMP snooping functionality, the ARP-ETHER TCAM must be configured in the double-wide mode using the CLI command, switch# hardware access-list tcam region arp-ether 256 double wide .

Procedure

  Command or Action Purpose
Step 1

switch(config)#ip igmp snooping vxlan

Enables IGMP snooping for VXLAN VLANs. You have to explicitly configure this command to enable snooping for VXLAN VLANs.
Step 2

switch(config)#ip igmp snooping disable-nve-static-router-port

Configures IGMP snooping over VXLAN to not include NVE as static mrouter port using this global CLI command. IGMP snooping over VXLAN has the NVE interface as mrouter port by default.

Step 3

switch(config)#system nve ipmc global index-size ?

Example:

 
switch(config)# system nve ipmc global index-size ?
<1000-7000> Ipmc allowed size

Configures the VXLAN global IPMC index size. IGMP snooping over VXLAN uses the IPMC indexes from the NVE global range on the Cisco Nexus 3000 Series switches with Network Forwarding Engine (NFE). You need to reconfigure the VXLAN global IPMC index size according to the scale using this command. Cisco recommends to reserve 6000 IPMC indexes using this CLI command. The default IPMC index size is 3000.

Step 4

switch(config)# ip igmp snooping vxlan-umc drop vlan ?

Example:


switch(config)# ip igmp snooping vxlan-umc drop vlan ?
<1-3863>  VLAN IDs for which unknown multicast traffic is dropped

Configures IGMP snooping over VXLAN to drop all the unknown multicast traffic on per VLAN basis using this global CLI command. On Cisco Nexus 3000 Series switches with Network Forwarding Engine (NFE), the default behavior of all unknown multicast traffic is to flood to the bridge domain.

Note 

IPv6 neighbor solicitation packets are dropped when this command is enabled. Therefore, IPv6 hosts are not resolved.