If you look at page 432, Table 9.1 in Doyle's "Routing TCP/IP" for the OSPF
interface state machine, you will see clearly that one of the events (6). is
"the expiration of the RouterDeadInterval without having received a Hello
from the DR or the BDR or both", which changes directly to the DR/BDR
election state. This implies that the DR/BDR election process is associated
with the Hello interval, not an LSA. It makes sense, because every Hello
packet states the DR and the BDR. If the DR goes down, how does it send an
LSA to notify anybody about it? I am not sure exactly what a "missed LSA"
means in this regard. The state diagram is probably the source from which
that actual software algorithms were derived.
JMHO
MLC
"David Armstrong" <[EMAIL PROTECTED]> wrote in message
8up5n1$src$[EMAIL PROTECTED]">news:8up5n1$src$[EMAIL PROTECTED]...
> This has been an awesome thread to me. Thanks everyone for the input.
> Evidently I'm not alone in being confused over BDR to DR promotion. The
> books and literature I've found have clearly stated that the event to
> promote BDR's to DR's is a missed LSA; however, the tests here show
> otherwise. Winston, I'm with you: I hope they never ask this on the test.
> I'll have to decide between what I believe to be right and what the book
> states as right.
>
> I still think there's a piece missing. 40 seconds to take over the
functions
> of DR seems like it could create routing delays or time outs on a large
> network. I'm going to continue to look for a definitive answer.
>
> Thanks Again,
>
> David
>
> ""David Armstrong"" <[EMAIL PROTECTED]> wrote in message
> 8uh8vj$c47$[EMAIL PROTECTED]">news:8uh8vj$c47$[EMAIL PROTECTED]...
> > Last night at our BSCN study group meeting in Dallas we had some
questions
> > about OSPF that we weren't able to resolve. If someone or ones could
> answer
> > these it would clarify some areas we're a little fuzzy on. Also, if
you're
> > iin the Dallas Ft. Worth area and would like to attend, we'd love to
have
> > you join us..
> >
> > Thanks for any help,
> >
> > David Armstrong
> >
> >
> > 1) What is the default time period that the BDR waits when listening to
> > LSA's from the DR before it decides that the DR is down and promotes
> itself
> > to DR. All the literature we could find simply said that the BDR waits
for
> > the specified time period but never said what that period is.
> >
> > 2) In a Point-to-Point network in which the router in Area 0 is
connected
> to
> > FR, ISDN, X.25 or ATM branch offices (networks), how does convergence
and
> > updates take place? From what we've found a DR and BDR is not elected in
a
> > strictly Point-to-Point network.
> >
> > I think an example would explain this question better: We have one 3620
> > router in our Ft. Worth office connected to an office in Houston (via
FR),
> > and office in Kansas City (via FR), an office in the DFW area (via ISDN)
> and
> > the owner's home (via ISDN). The 3620 is behind a firewall (Pix 520) and
> the
> > firewall is connected to a 1720 going to the Internet. I'd like to
> implement
> > OSPF on our network simply for the experience. However, I don't have 2
> > routers internally on our Ethernet LAN that can be configured for Area 0
> and
> > elected to DR and BDR. All other routers connected to that router are
via
> > NBMA Point-to-Point connections. Since I only have one router on the
> > Broadcast Multiaccess network (the 3620) and routers connected via PtoP
> > don't participate in DR and BDR elections, how would updates occur? Can
> > their only be one DR (in this case the 3620)?
> >
> > 3) The books and tutorials all state that "router ospf 6" defines ospf
on
> > the router with a process ID of 6. They then all say that you shouldn't
> > define more than one process. Does that mean that you can have a router
> with
> > the following:
> >
> > router ospf 6
> > network 10.100.0.0 0.0.255.255
> >
> > router ospf 7
> > network 10.200.0.0 0.0.255.255
> >
> > If this is an allowed configuration, what kind of instances would it be
> used
> > for? Also, exactly what is the process ID used for?
> >
> >
> >
> >
> > _________________________________
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> >
>
>
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