Controller Based WLANs

Q:

Is it mandatory to enable keepalives on both sides while configuring L2 GRE tunnel ?

We need to enable keepalives in case we are using tunnel-group feature to support multiple tunnels.

Tunnel group feature will be used on the controllers which are configured for multiple L2 GRE tunnels carrying the traffic for the same vlan. The tunnels will be terminating on different controllers. At a given time, one tunnel will be active & other one will be in standby mode.

Example: Master controller has 2 GRE tunnels terminating on 2 different DMZ controllers (different datacenters). Both the tunnels carry traffic for guest vlan (say vlan 400).

In this case, tunnel group will be configured on master controller & both tunnels will be added to it. However, there won't be any tunnel group configured on the DMZ controllers as they have a single GRE tunnel terminating on them.

Keepalive needs to be enabled only to send out keepalive requests. To respond to a request from remote end, keepalive does not need to be enabled. This is intended behavior. So the tunnel is not expected to go down in this case.

If there is no tunnel-group on DMZs then there is no need to enable keepalive there.