Subject: [Autoconf] Asymmetric Reachablity

From: Ian Chakeres <[email-masked]>
Date: Fri, 29 Sep 2006 10:01:52 -0700

In recently revising the MANET architecture document, I've been  
thinking about asymmetric reachability.

Asymmetric Reachability
       A link where non-reflexive and/or non-transitive reachability  
is part of normal operation.  Non-reflexive reachability means  
packets from X reach Y but packets from Y don't reach X. Non- 
transitive reachability means packets from X reach Y, and packets  
from Y reach Z, but packets from X don't reach Z. Many radio/wireless  
interfaces exhibit these properties.

I wanted to solicit discussion on whether the Autoconf group should  
create a protocol that works in the presence of asymmetric  
reachablity, multihop networks, or both?

What is your opinion?

Ian Chakeres

_______________________________________________
Autoconf mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/autoconf

---

From: "Charles E. Perkins" <[email-masked]>
Date: Fri, 29 Sep 2006 12:59:23 -0700

Hello Ian,

I thought it was already a given that the autoconf working group
would be dealing with multihop networks.  Is this not true?

If we have multihop, then nontransitive reachability is overcome
almost by definition.

I think we ought to solve the symmetric reachability case first,
and then think about how to go about solving the problems
introduced by asymmetric reachability.  The latter problem is
very very hard to solve, and the solution will almost certainly
exhibit poorer performance than the solution for the reachable
case.  Maybe the intermediate situation, in which a link is not
symmetric but still passes data in both directions, would be a
suitable next target if we ever get past hop count as the only
metric.

Regards,
Charlie P.

ext Ian Chakeres wrote:
>       A link where non-reflexive and/or non-transitive reachability is 
> part of normal operation.  Non-reflexive reachability means packets 
> from X reach Y but packets from Y don't reach X. Non-transitive 
> reachability means packets from X reach Y, and packets from Y reach Z, 
> but packets from X don't reach Z. Many radio/wireless interfaces 
> exhibit these properties.
>

-- 
Please address return e-mail to [email-masked]