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

Dear Richard,

see answer below

> 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?
> 

Yes. According to section 5.2.4. Hello packets contain a TLV that will:

"advertize the costs of links towards ALL its symmetric MANET neighbors. 
  If the router has several MANET interfaces, links to ALL the symmetric 
MANET neigbors over ALL the MANET interfaces of the router MUST have 
their costs listed."

Thus MPR selection algorithms take into account neighbors on multiple 
MANET interfaces, similar to the way OLSR works. Therefore in your 
example, A will select B as MPR, and will bring up an adjacency with B.

Emmanuel

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