Subject: [manet] backup routes

From: "Nast, Douglas P" <[email-masked]>
Date: Thu, 11 Apr 2002 12:09:03 -0700

Do any of the proposed pro-active manet routing protocols support an idea
analogous to the feasible successor concept in EIGRP?   That is, a
guaranteed loop-free backup route is maintained in a topology database for
immediate use when the link to the best path goes down?   

Doug Nast

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From: "Nast, Douglas P" <[email-masked]>
Date: Fri, 12 Apr 2002 08:10:27 -0700

Thanks Richard.

I am interested any feasible manet DVs, and noted that EIGRP claims
convergence comparable to link state because it retains backup routes.  I
was wondering if anyone thought this idea worth exploiting in Manet
protocols. 

As you say, with link states replicated topology database discovering
loop-free alternates is not an issue.  

I will take a look at DSDV.

Doug Nast 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, April 11, 2002 5:09 PM
To: Nast, Douglas P
Cc: [email-masked]
Subject: Re: [manet] backup routes 

> immediate use when the link to the best path goes down?   

Doug,

In TBRPF, when a route fails, the source tree and routing table
are updated immediately, based on the topology database, to provide 
immediate rerouting (even if the new path is longer, unlike EIGRP 
as explained below).  Since TBRPF is a link-state protocol, the source 
node knows the entire path (and therefore knows that it is loop free).  
EIGRP is a distance-vector protocol, and must send "query" messages
if the distance to some destination increases, to ensure loop freedom.
EIGRP is not being considered for MANETs.  DSDV is another distance-vector 
protocol that is a better candidate for MANETs.  

Richard

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From: "Nast, Douglas P" <[email-masked]>
Date: Fri, 12 Apr 2002 08:10:27 -0700

Thanks Richard.

Doug Nast 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, April 11, 2002 5:09 PM
To: Nast, Douglas P
Cc: [email-masked]
Subject: Re: [manet] backup routes 

Doug,

Richard