OTV Unicast Transport mode packet flow

[brju]

Hi All,

Bit confusing : Is IGMP involved if OTV configured with unicast mode ?

If so what can we check for IGMP command to verify control plane converged between two DCI / OTV site like sho ip mrou for multicast OTV .

OR anything else ?

I appreciate your helps.

Many Thanks,

[Orlando Barboza]

Hello Brju,

The answer to your question is no, if you are running OTV in unicast mode IGMP is not involved, instead OTV will use an adjacency server to build up the adjacency between sites.

An adjacency server is responsible for informing all the other existing edge devices if there is any addition or loss of an edge device. Based on the reachability information, an edge device can further communicate directly with another edge device by using the unicast data path.

An adjacency server distributes the unicast replication list (URL) of all edge device addresses to the members of the overlay network. Each edge device then uses this list to encapsulate multicast packets in a unicast IP header destined for the unicast IP address of each remote edge device.

You can find more information about this type of OTV setup in the link below:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/OTV/config_guide/b_Cisco_Nexus_7000_Series_NX-OS_OTV_Configuration_Guide/adv-otv.html#concept_AC4202C6AFF243E6B7AD182D59AFED88

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/wan_otv/configuration/xe-3s/wan-otv-xe-3s-book/wan-otv-adj-server.html --> this one is not for Nexus but the same logic applies.

HTH