Re: [Ospf-manet] Re: Regarding MPR-OSPF

Richard Ogier <> Wed, 14 March 2007 00:24 UTC

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Date: Tue, 13 Mar 2007 16:24:26 -0800
From: Richard Ogier <>
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To: Emmanuel Baccelli <>
Subject: Re: [Ospf-manet] Re: Regarding MPR-OSPF
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Emmanuel Baccelli wrote:

> To clarify a point which you indicate that you missed concerning the 
> synch router: the willingness parameter influences a routers 
> forwarding ability only. If a synch router is outside the MANET, then 
> according to the I-D there exists a hybrid router which will 
> synchronise with its whole neighbourhood, thus fulfilling the synch role.


There still seems to be a problem when a router has multiple
MANET interfaces.  You define a hybrid router as follows.

Hybrid router  - a router which has OSPF interfaces of several types,
including the MANET type.

So a router with only MANET interfaces is not a hybrid router.
Consider a router A that has only one MANET interface, but has
only 1-hop neighbors and no 2-hop neighbors on this interface.
(I.e., Hellos received from neighbors on this interface advertise
only routers that are neighbors of router A itself.) As a result,
router A has no MPRs.  Assume it also has no MPR selectors.

A ----- B ----- C

Now suppose router A has a neighbor B which has two MANET
interfaces, one of which connects it to router A, and the other
of which connects it to router C, which is not a neighbor of A.
Assume router C has the largest RID and is therefore the synch router.
Therefore, since router A is not a synch router (nor a neighbor of a
synch router) and has no MPRs or MPR selectors, it has no adjacencies!

Therefore, it still looks like you need to select a synch router
for each MANET interface, or redefine a hybrid router to include
routers with multiple MANET interfaces.  Am I missing something?


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