Subject: [manet] Q. about RFC3561

From: YAMADA Tatsuya <[email-masked]>
Date: Thu, 24 Jul 2003 18:30:38 +0900

Hello all,

I have a question about RFC3561.  Section 6.1. is written as below,

>6.1. Maintaining Sequence Numbers
(snip)
>   guarantee the loop-freedom of all routes towards that node.  A
>   destination node increments its own sequence number in two
>   circumstances:
>
>   -  Immediately before a node originates a route discovery, it MUST
>      increment its own sequence number.  This prevents conflicts with
>      previously established reverse routes towards the originator of a
>      RREQ.

Does "a node" in first item mean "an originator" ?

If so, it shold be written like that explicitly.

If not so, could you tell me when a destination node has to originate a 
route discovery ?
(When a destination node will reply a RREP, a route from a destination to 
an originator (and vice versa) has been already established, I think.)

Or does "a node" mean both ?

Best Regards,

----
YAMADA Tatsuya / mailto:[email-masked]
Software Technology Group 2, Software Engineering Center, Toshiba Corp.
Tel: +81-44-549-2404 / Fax: +81-44-549-5484

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From: Ian Chakeres <[email-masked]>
Date: Thu, 24 Jul 2003 09:49:51 -0700

This paragraph is not describing management of routing table entries
but each nodes own "destination sequence number".  In AODV each node
maintains it's own destination sequence number therefore specifying
originator or destination is slightly redundant (but correct in the
context of each bullet) in this paragraph.  I'll try to make it more
clear in future drafts.

Does this re-write remove the confusion?

   guarantee the loop-freedom of all routes towards that node.  A node
   increments its own sequence number in two circumstances:

   - Immediately before a originating node starts a route discovery, it
      MUST increment its own sequence number.  This prevents conflicts
      with previously established reverse routes towards the
      originator of a RREQ.

   - Immediately before a destination node issues a route reply in
     response to a RREQ, it MUST update its own sequence number to the
     maximum of its current sequence number and the destination
     sequence number in the RREQ packet.

Ian Chakeres

>YAMADA Tatsuya wrote:

---

From: YAMADA Tatsuya <[email-masked]>
Date: Sat, 26 Jul 2003 16:06:21 +0900

Hello,

Thank you for your reply.
Added word and your comment solve my misunderstanding.

I think that it is better to rewrite it as described below
in a next version draft.

Best regards,

----

---

From: Casey Carter <[email-masked]>
Date: Sat, 26 Jul 2003 13:06:00 -0500

>     sequence number in the RREQ packet.
Doesn't this text (from Section 6.1) conflict with:

    6.6.1. Route Reply Generation by the Destination

    If the generating node is the destination itself, it MUST increment
    its own sequence number by one if the sequence number in the RREQ
    packet is equal to that incremented value. Otherwise, the
    destination does not change its sequence number before generating the
    RREP message. The destination node places its (perhaps newly
    incremented) sequence number into the Destination Sequence Number
    field of the RREP, and enters the value zero in the Hop Count field
    of the RREP.

Is there an internal inconsistency in the document, or am I missing 
something?

-- 
Casey Carter
[email-masked]
[email-masked]
AIM: cartec69