Re: Waiting State Question

[Erblichs <[e-mail]>]

Sorry,

	I have to kind of disagree on two accounts with the
	spec vs implimentations..

	First, if the interface is a passive interface. I
	think passives interfaces are after the spec, thus
	it fits as an exception. But in my opinion, passive
	interfaces have a equiv as a infinite waiting
	period.

	Second, "in the case where more than 1 router"
	is declaring itself as the DR, shouldn't enough 
	time pass (1.5 to 2x) hello interval pass to identify
	this situation before exiting wait state and
	poss determine whether 2-ways are forming.  Yes,
	it could/should exit early, but on that first 
	hello???

	Thus, this section of the spec covers the rare simple 
	case where no BDR has yet been elected or is eligible
	to be elected.

	Mitchell Erblich
	-----------------
	
	

Kishore Rao wrote:
> 
> Not NeighborChange but Backupseen
> 
> "If the neighbor is both declaring itself to be Designated
>             Router (Hello Packet's Designated Router field = Neighbor IP
>             address) and the Backup Designated Router field in the
>             packet is equal to 0.0.0.0 and the receiving interface is in
>             state Waiting, the receiving interface's state machine is
>             scheduled with the event BackupSeen."
> 
> > I think the NeighborChange events are ignored while an interface is in
> waiting
> > state.
> >
> > Thanks,
> > Mukul
> >
> >
> > Quoting Kishore Rao <[e-mail]>:
> >
> > > The question was not about how DR or BDRs are elected. John's question
> was
> > > if the router should exit Wait Timer (and run DR election) on receving
> Hello
> > > from a router declaring itself as DR. Well, from section 10.5 it should.
> > >
> > > Kishore
> > >
> > >
> > > > My guess is that if an interface comes out of the waiting state on
> > > receiving a
> > > > Hello from DR (without having received a Hello from BDR), it may elect
> > > itself
> > > > as BDR. This way many routers may elect themselves as BDR. Now all
> these
> > > BDR
> > > > claimants (except one) will ultimately take their claims to BDRship
> back
> > > but in
> > > > the process each router on the LAN may have to do several DR
> elections.
> > > >
> > > > Here is a paper we wrote recently that may shed further light on this:
> > > > http://cs.uwm.edu/~mukul/ospflan.pdf
> > > >
> > > > Thanks,
> > > > Mukul
> > > >
> > > > Quoting John Smith <[e-mail]>:
> > > >
> > > > > Hi,
> > > > >
> > > > > When a router comes up it starts the Wait Timer before it elects the
> > > DR/BDR.
> > > > > It either
> > > > > waits for the Wait Timer to expire or it waits for a router
> declaring
> > > itself
> > > > > as the BDR
> > > > > before it decides that it needs to get out of the 'Waiting' state
> (it
> > > does
> > > > > this by
> > > > > generating the Backupseen event).
> > > > >
> > > > > My question is why does it wait only for the BDR? Why not the DR? It
> can
> > > when
> > > > > it recieves
> > > > > a HELLO from the DR know that their exists a DR and a BDR. Why not
> then
> > > get
> > > > > out of the
> > > > > 'Waiting' state?
> > > > >
> > > > > Thanks,
> > > > > John
> > > > >
> > > > > Send instant messages to your online friends
> > > http://uk.messenger.yahoo.com
> > > > >
> > >