Subject: [AAA-WG]: Issue 98:

From: Pat Calhoun <[email-masked]>
Date: Mon, 27 Aug 2001 12:59:33 -0700

This issue was raised basically because the use of the term alternate, and
the introduction of the Alternate-Peer, caused lots of confusion. Since 
Issue 117 removed the Source-Route, this isn't much of an issue anymore,
but I did decide to try to clean up some of the language (and hopefully
succeeded).

New text:

5.1  Peer Connections

   Although a Diameter node may have many possible peers that it is able to
   communicate with, it may not be economical to have an established 
   connection to all of them. At a minimum, a Diameter node SHOULD have
   an established connection with two peers per realm, known as the 
   primary and secondary peers. Of course, a node MAY have additional 
   connections, if it is deemed necessary. Typically, all messages for 
   a realm are sent to the primary peer, but in the event that failover 
   procedures are invoked, any pending requests are sent to the secondary 
   peer. However, implementations are free to load balance requests between 
   a set of peers.
 
   Note that a given peer MAY act as a primary for a given realm, while 
   acting as a secondary for another realm.

   When a peer is deemed suspect, which could occur for various reasons,
   including not receiving a DWA within an alloted timeframe, no new
   requests should be forwarded to the peer, but failover procedures are
   not invoked. When an active peer is moved to this mode, additional
   connections SHOULD be established to ensure that the necessary number
   of active connections exists.

   There are two ways that a peer is removed from the suspect peer list:
      1. The peer is no longer reachable, causing the transport connection
         to be shutdown. The peer is moved to the closed state.
      2. Three watchdog messages are exchanged with accepted round trip
         times, and the connection to the peer is considered stabilized.

   In the event the peer being removed is either the primary or secondary, 
   an alternate peer SHOULD replace the deleted peer, and assume the role 
   of either primary or secondary.

Comments appreciated,

PatC