Subject: [AAA-WG]: Issue 222: Routing within a domain

From: Johan Johansson <[email-masked]>
Date: Wed, 07 Nov 2001 10:45:28 +0100

Hi all.

I promised Pat I'd email the list about this one and elaborate about the 
issue. The issue is that the protocol forces a certain network topology, 
which may or may not be a problem. We just observed that this is indeed 
the case and would like to get some more comments about it.

For reference (approximation of 6.1):

1. If there is a destination host, and it's us, handle msg locally
2. If there is a destination host, and it's one of our peers, pass the 
msg to this peer
3. If there is a destination realm, consult the routing table
a) destination realm is one of the realms we handle locally - handle 
message locally
b) destination realm is handled by someone else - pass the message to 
the appropriate peer

This algorithm disallows relay nodes inside a realm, e.g. assume that 
the following three diameter entities are all within the same realm, say 
x.com.

AAAH ----------- R ----------- HA

Assume AAAH wants to send a message to HA and sets destination host and 
destination realm accordingly and let's see where the algorithm leads us.

1. AAAH is not the destination host, so move on.
2. HA is not a peer of AAAH, so move on.
3. It's in our realm, so... uhm.. handle locally?

The suggested fix is to use subrealms. The above scenario works if R and 
HA is e.g. in the realm s.x.com.

j