Re: [DNA] Re: RS/RA Exchange

[Brett Pentland <brett.pentland@eng.monash.edu.au>]

Erik Nordmark wrote:
>>So, I can dust off some "historic" code for this.  DVMRP has a HELLO
>>message like many other routing protocols.  But, DVMRP uses them to
>>announce reachability and discovery.  That is, peer routers on a link
>>look in the other routers' HELLO messages for their own addresses.
>>This allows them to determine when they have been "discovered" by
>>their peers.
>>
>>Could we mimic this and have some type of announcement message that
>>a router would send out with all the other routers' addresses that
>>it has heard from?
> 
> 
> I don't think for this case (RA collision avoidance) we need the
> confirmation of bidirectional reachability between the routers;
> allowing each router to have an ordered list where the lists on
> the different routers are loosly and approximately consistent should
> be sufficient. Doesn't mean it would hurt to know that the routers
> have a consistent view though.
> 
> One way to build this is to just interpret what is currently in the RA
> messages.
> Should this be insufficient and some new information needs to be
> exchanged between the routers than it makes sense reusing something
> which has already been built.
> I don't know if there are related things that the routers might want
> to advertise and coordinate with eachother.

Having this information might be useful for coordinating a link 
identifier if it becomes desirable to use one for DNA.  Greg, JinHyeock 
and I proposed a method for coordinating a link identifier last year 
(http://www.watersprings.org/pub/id/draft-pentland-mobileip-linkid-00.txt) 
but it might be good to have a method that is useful for other tasks as 
well.

Brett.