Subject: [Dime] Multiple transport connections between peers

From: Max Bacik <[email-masked]>
Date: Wed, 20 May 2009 14:42:03 +0100

Hi All,

===============================================================================
* RFC 3588, Section 2.1: *

A given Diameter instance of the peer state machine MUST NOT use more 
than one
transport connection to communicate with a given peer, unless multiple
instances exist on the peer in which case a separate connection per 
process is
allowed.

===============================================================================

A previous conversation 
(http://www.ietf.org/mail-archive/web/dime/current/msg00803.html) seems 
to conclude that the above statement means that multiple Diameter nodes 
may reside on the same host, each using a different alias to that host 
as their Origin-Host and each using its own port (only one could use 3868).

However, this seems to conflict with the RFC, firstly because the use of 
port 3868 is mandated, and secondly because of the wording of the 
statement. It says "a given Diameter instance of the peer state 
machine... ...unless multiple instances exist *on the peer*...". This 
seems to imply that it is multiple transport connections between two 
Diameter nodes - which seems to present quite a few problems for the 
peer state machine and for message routing. The above wording also still 
exists in the latest BIS draft (17) of the RFC.

Can anyone shed some light on this topic?

Thanks,

Max