[Dime] Alternate (secondary) peers in diameter commands

[Krishna Prasad <[e-mail]>]

Diameter experts,
          Diameter base protocol addresses some level of redundancy mechanisms by defining failover and failback procedures and Device Watchdog messages etc. For sure, this simplified or standardized the failover procedures across different implementations which we claim one of the benefits of diameter over RADIUS.
Though the diameter base protocol supports facilities for when to trigger failover/failback procedures, retransmissions  etc..but it does not exactly specify to which alternate peer a diameter node should failover in case of primary peer failure. This is because a diameter node does not know who is secondary for a given primary peer and this is completely left to the implementations choice (probably as a configuration or DNS etc...). What I mean here is, we can left it open for the users to configure secondary peers for a given primary peer. So is it not a good idea to support for diameter nodes to exchange the secondary peers identities also during CER/CEA?
For example client sends CER with its list of secondary peers and server responds with its list of secondary peers in CEA. If there is any change in this list of secondary peers the peers can dynamically exchange this information using 'Diameter Capabilities Update' application. (draft-ietf-dime-capablities-update-07).

I am not sure if this option is already discussed in the working group earlier, if not I would like to know the experts opinion  on this. Does it make sense, completely useless , out of diameter scope, too late to incorporate this in base etc...?


Prasad.
Sandvine Networks