Subject: RE: [manet] REF: AODV (Updating and creating reverse/forward rout e)

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Wed, 9 Oct 2002 08:10:04 -0600

Hi, Sibusisiwe,

Please excuse me for breaking off our conversation yesterday, but something
came up and I had to go.

Let me relate the sequence of events, as I see it.

When a node receives the RREQ, it stores the reverse path on that RREQ as a
temporary route.  This route will include the previous node.  Then, the node
checks the sequence number in the RREQ.  If that RREQ is a duplicate of a
previous RREQ, it dumps the RREQ and temporary route information.
Forwarding the RREQ would be duplication and the presumption is that the
route taken to deliver that earlier RREQ was probably a better one.

If the RREQ is not a duplicate, the node forwards it.  Then, the node looks
at the temporary route back to the originator taken from that RREQ.  One of
four things will happen:

1.  If the node does not already have a route back to the Originator, the
reverse route in the RREQ is the only information the node has on that
route, so it will make the temporary route the "official" route back to the
Originator.

2.  If the node already has a route back to the Originator in its tables,
but that route is older (has a smaller sequence number), the node will
replace that route with the fresher route in the RREQ.

3.  If the node already has a route back to the Originator and its sequence
number is the same as that in the RREQ, the node will pick the better of the
two routes and store that as the "official" route.

4.  If the node already has route back to the Originator and that route is
newer (has a higher sequence number), the node will discard the temporary
route and retain the original one.

The end result is that the node attempts to determine a route back to the
Originator on the basis of available information without initiating a RREQ
of its own.

John Mullen

-----Original Message-----
From: Sibusisiwe Chiyangwa [mailto:[email-masked]]
Sent: Tuesday, October 08, 2002 9:34 AM
To: Mullen, John P. (Contractor)
Subject: Re: [manet] REF: AODV (Updating and creating reverse/forward
route)

Mullen

We are creating two reverse routes (1) to the previous hop (2) to the
Originating node. WHY?

It is suggested that you first create a reverse route to the previous
node, then another reverse route to the Originating node. Obviously this
reverse route to the Originating node has the previous hop as its next
hop to the Originating node. Why then in the first place did we create a
reverse route to the previous hop? 

The RREP will find its way to the Originating node because I have a
reverse route to the Originating node with that previous node as the
next hop to the Originating node.
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From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Wed, 9 Oct 2002 08:10:04 -0600

Hi, Sibusisiwe,

John Mullen

-----Original Message-----
From: Sibusisiwe Chiyangwa [mailto:[email-masked]]
Sent: Tuesday, October 08, 2002 9:34 AM
To: Mullen, John P. (Contractor)
Subject: Re: [manet] REF: AODV (Updating and creating reverse/forward
route)

Mullen