Subject: RDMAR vs AODV: Second call for correction in IETF proceedings' page

From: George Aggelou <[email-masked]>
Date: Tue, 07 Mar 2000 12:09:23 +0000

Hello Scott,

Referring to my mail below, as this was sent a month ago, nothing has
been changed yet in IETF proceedings' page
(http://www.ietf.org/proceedings/99nov/unedit/manet-minutes-99nov.txt).

In your last mail you said that you would correct the description of
RDMAR in your report which however has not been done yet!

As the main author of the draft, I am kindly asking you *again* to
change the incorrect statement(s) in your report as these are reported
in my last mail (see below).

Please notify the WG as soon as this is fixed.

Regards,
George A.

***************************************************************************

Hello Scott,

I want to make a few clarifications on the description of RDMAR as this
is composed from you and advertised in IETF's MANET  minutes 
(http://www.ietf.org/proceedings/99nov/unedit/manet-minutes-99nov.txt)
and which contains a *categorically incorrect* statement.

You mention: "The protocol is structured along the lines of a distance
vector algorithm,uses sequence numbers to maintain loop freedom, and is
in several ways similar to AODV. The key concept behind RDM is that a
query flood can be localised by knowing the relative distance (RD)
between two terminals. "

We had a discussion last November and explained to you that RDMAR has
*nothing* in common with AODV.  So, I still can not see why you mention
that RDMAR is similar to AODV. If you still believe so, could you please
identify the similarities and inform the group if you find any?

First, the main and distinguished property of AODV is the dest_seq_nos
which are not used in RDMAR protocol as the discovery is end to end and,
thus, there is no fear for stale route in RREP messages.
Second, RDMAR makes use of sequence numbers during the Route Discovery
procedure (called RREQ_ID in the I-D) to ensure loop freedom.  AODV also
uses seq_nos but this is not a specific property of AODV protocol as
this is a well-establised technique to ensure loop freedom.
Third and most important, RDMAR presents a generic concept on the
maintenance of active paths (Route Maintenance procedure).  The Route
Maintenance algorithm in RDMAR is a distributed operation that exploits
the spatial relationship of nodes when a failure along an active route
occurs and depending on the relative
distance of the node that reports the failure from the calling and
called nodes, two heuristics are considered:

        a) if its relative distance from the called node is smaller or
           equal to this from the calling node, then RDM is to be
           applied to localise the repair of the failed route on the
           region of the network where the failure occurs; otherwise,
        b) the node proceeds and informs the calling node about the
           failure to deliver the call through this path.
        
For a detailed version and thorough understanding of the protocol,
please have a look at the paper attached herein or the RDMAR Internet
Draft.  

>From the above, I am kindly asking you to update the short description
of RDMAR in IETF's minutes page as this is currently put on and notfy
the group as soon as this is fixed.

Regards,
George A.

-- 
*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.     
George Aggelou			     	
Centre for Communications Systems Research   
Mobile Communications Research Group      		
University of Surrey  		     

http://www.ee.surrey.ac.uk/Personal/G.Aggelou
*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.

---

From: Joe Macker <[email-masked]>
Date: Tue, 07 Mar 2000 11:17:49 -0500

George:

I believe Scott requested this change already.

-Joe