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RE: [manet] Last Call: <draft-ietf-manet-olsrv2-multipath-12.txt> (Multi-path Extension for the Optimized Link State Routing Protocol version 2 (OLSRv2)) to Experimental RFC

2017-05-09 05:13:56
A few comments on this draft.

IPv6 specifies complete source routing. But this specification can only 
consider what happens within the MANET. So for a packet from somewhere in the 
MANET to somewhere well outside the MANET, the packet must be source routed to 
the gateway between MANET and rest of Internet, and not source routed after 
that. This I think should be explicitly mentioned. Whether that is considered 
compliant with IPv6 I leave to others.

7.1 SR_addr would better say "originator" address rather than "network" 
address. (That makes it an address without a netmask, see RFC 7181.)

8.1 This is suggesting creating TC messages that have on neighbour addresses 
but have only a SOURCE_ROUTE TLV. This is not the design I would have suggested 
as consistent with how I would expect an extension to OLSRv2 to do things. We 
need to consider two kinds of routers: those sending TC messages anyway, those 
that (other than this extension) do not. In the former case you could just add 
the SOURCE_ROUTE TLV to those TC messages it sends. Then that information is 
maintained up to date. Routers that don't usually send TC messages could send 
TC messages with just that TLV. But then there's an issue over validity time. A 
parameter SR_HOLD_TIME_MULTIPLIER is introduced. There's no need for that - you 
can simply incorporate that into the validity time recorded in the message. 
That avoids a need to handle the two cases of routers differently. There is 
then an oddity that you get some routers sending TC messages with normal 
validity times and addresses, and some that can be sent !
 less frequently with no addresses and longer validity times. But that's 
suspect - note that it's not done in OLSRv2 for attached networks (another 
reason to send TC messages although no neighbours need reporting). That's 
because longer intervals make reacting to new routers joining (and network 
reassembly after fragmentation) slow. Rather a better design would simply be to 
add SOURCE_ROUTE TLV to normal TC messages. When sending TC messages for just 
that reason, that could be just the usual case, but you could allow as an 
option in this case to send less frequently with validity time increased 
accordingly. When not using that option, once a router needs to send a TC 
message, it could then decide to report neighbours, increasing the topology 
distributed and allowing more routes, this also being an option.

8.3 second bullet. You should here (and possibly elsewhere) exclude routers 
with routing willingness zero.

8.3 there seems to be an inconsistency. When operating proactively and no 
multiple routes, drop the packet, but reactively use standard routing. The 
latter seems more appropriate in the former case also.

9 CUTOFF_RATIO. Insists of strictly, but as defined earlier, may be >= 1`.

-- 
Christopher Dearlove
Senior Principal Engineer
BAE Systems Applied Intelligence Laboratories
__________________________________________________________________________

T:  +44 3300 467500  |  E: chris(_dot_)dearlove(_at_)baesystems(_dot_)com

BAE Systems Applied Intelligence, Chelmsford Technology Park, Great Baddow, 
Chelmsford, Essex CM2 8HN.
www.baesystems.com/ai
BAE Systems Applied Intelligence Limited
Registered in England & Wales No: 01337451
Registered Office: Surrey Research Park, Guildford, Surrey, GU2 7YP


-----Original Message-----
From: manet [mailto:manet-bounces(_at_)ietf(_dot_)org] On Behalf Of The IESG
Sent: 20 April 2017 22:51
To: IETF-Announce
Cc: manet(_at_)ietf(_dot_)org; 
draft-ietf-manet-olsrv2-multipath(_at_)ietf(_dot_)org; 
manet-chairs(_at_)ietf(_dot_)org
Subject: [manet] Last Call: <draft-ietf-manet-olsrv2-multipath-12.txt> 
(Multi-path Extension for the Optimized Link State Routing Protocol version 2 
(OLSRv2)) to Experimental RFC

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The IESG has received a request from the Mobile Ad-hoc Networks WG
(manet) to consider the following document:
- 'Multi-path Extension for the Optimized Link State Routing Protocol
   version 2 (OLSRv2)'
  <draft-ietf-manet-olsrv2-multipath-12.txt> as Experimental RFC

The IESG plans to make a decision in the next few weeks, and solicits final 
comments on this action. Please send substantive comments to the 
ietf(_at_)ietf(_dot_)org mailing lists by 2017-05-04. Exceptionally, comments 
may be sent to iesg(_at_)ietf(_dot_)org instead. In either case, please retain 
the beginning of the Subject line to allow automated sorting.

Abstract


   This document specifies a multi-path extension for the Optimized Link
   State Routing Protocol version 2 (OLSRv2) to discover multiple
   disjoint paths, so as to improve reliability of the OLSRv2 protocol.
   The interoperability with OLSRv2 is retained.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-manet-olsrv2-multipath/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-manet-olsrv2-multipath/ballot/


No IPR declarations have been submitted directly on this I-D.




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