OTV adjacency server down

[ivan widjaja]

Hi,

if i use OTV unicast mode.

and both primary and secondary adjacency server is down, what happen to existing OTV network?

will the existing OTV connection still running on other edge device ?

thanks,

ivan

[Steve Fuller]

Hi Ivan,

When using two adjacency servers they're configured and used as a primary and secondary. The replication list from the primary is used until such time as an OTV Edge Device detects it is no longer available i.e., by loss of IS-IS hellos, at which time the edge devices will start to use the replication list from the secondary adjacency server.

As per the documentation "OTV will stale the replication list entries with a timer of 10 minutes". I've not tested simultaneous failure of both adjacency servers, but I would imagine that if the secondary adjacency server is also lost, then at best you would have a 10-minute period before the replication list of the secondary became stale, at which point you would lose connectivity between your remaining OTV edge devices.

Given that the primary and secondary adjacency servers would typically be located in different sites, what failure scenario are you considering whereby you lose both adjacency servers at the same time?

Regards

[ivan widjaja]

Hi Steve,

for 2 sites scenario, i just wondering if there is any advantage for placing primary and secondary adjacency server on different sites.

[jkilleda]

Hello Ivan,

OTV adjacency server down
The OTV Edge Device must be configured to use both the Primary and Secondary Adjacency Servers. The sequence of adjacency server address in the configuration determine primary or secondary adjacency server role. This order is relevant since an OTV edge device will always use the neighbor-list provided by the Primary Adjacency Server, unless it detects that specific device is not available anymore , so the edge device will be working with OTV in it , it’s only the reachability with respect to the servers that goes off.