Subject: Re: node routing status

From: Marc Pearlman <[email-masked]>
Date: Fri, 18 Feb 2000 06:26:17 -0500

Hi all,

How about if a node reduces its router role by disabling packet forwarding 
only to/for certain neighbors, rather than completely dropping out?  Finer 
control would allow a node to maintain links that appear essential for full 
network connectivity.  (I say "appear" because a node may only have a 
partial snapshot of the current network topology.)

In the case of reactive routing protocols, a node could choose to relay a 
route request only TO certain neighbors, or discard incoming route requests 
received FROM certain neighbors.  For proactive schemes, a node could 
choose to ignore neighbor discovery HELLOs (or I-HEAR-YOUs) from certain 
neighbors.  Effectively, we're producing link failure (at least from the 
perspective of the network layer).

This approach has a nice side benefit for reactive routing protocols. 
 Since only route requests (and not data packets) are being discarded, 
existing connections aren't terminated.  The node only cuts back on its 
participation in future routes.  (If this doesn't sufficiently reduce its 
relay traffic then data packets could be dropped as well).

--

I like the notion of a network-wide "good citizen" policy.  If you allow 
nodes to opt out of being routers, you should also provide an incentive for 
them to stay on as routers.  For example (admitttedly simplistic and 
short-sighted), a node can send 1 of its packets for every n packets that 
it relays.  No doubt, there are better policies to achieve fairness 
(although it's not 100% clear to me what fair means in this context).

---

From: Chai Keong Toh <[email-masked]>
Date: Fri, 18 Feb 2000 10:35:57 -0500

> partial snapshot of the current network topology.)

This may make things a bit too complicated for the user.. Maybe this
is good for security?

> perspective of the network layer).

This may have implications for certain applications that rely on 
neighboring nodes for services. This could be a policy issue..

> relay traffic then data packets could be dropped as well).

Fairness kinda contradicts with collaboration. The "opt-out" option
may be useful for large ad hoc networks with rich connectivity.

-- 
Prof. C-K. Toh, 
Director, Mobile Multimedia & HiSpeed Network Lab, 
School of Electrical and Computer Engineering
Georgia Institute of Technology, Atlanta, Georgia
GA 30332, USA. Fax: 404 894 7883 Tel: 404 894 7468 
URL: www.ece.gatech.edu/~cktoh/
--------------------------------------------------