Scott,
After further study of the DR/BDR election process
on bcast networks I can confirm that an LSA is created
between the 2-way state and the EX-Start state, this
is a type 2 OSPF packet and is unicast from the DR to
the BDR.
A second LSA is created after the FULL state, this
is a type 4 OSPF packet and is multicast to 224.0.0.5
i.e all OSPF routers to let them know that an
adjacency has been successfully formed.
HTH,
Phil.
--- Phil Barker <[EMAIL PROTECTED]> wrote: >
Scott,
> I'm currently working on OSPF myself and
> believe
> your question has already been answered in an
> earlier
> post.
> I have found using a Sniffer very helpful, used
> in combination with the debug commands you mention.
> If you add 'debug ip ospf packet' you can start to
> match the sniffer trace directly with the debug
> trace.
>
> So you can see the stateful world of the Router
> versus
> the network frames that have been generated.
>
> Word of warning though, and something I have been
> suspicious of for some time. You cannot take the
> word
> of Debug to absolutely i.e as a software tool it is
> seen by very few people compared to an Analyser and
> as
> such I believe contains proportionately more bugs.
>
> It also can get a trace out of sequence with what
> really is happening on the wire, however, if you
> look
> out for sequence numbers and checksums you can get
> it
> back in step.
>
> Regards,
>
> Phil.
>
> --- scott <[EMAIL PROTECTED]> wrote: > Dear
> OSPF
> gurus:
> >
> > I am probably missing a very basic point here as I
> > am somewhat new to
> > OSPF. I have been debugging ospf adjacency, ospf
> > events, ospf flood
> > plus some others. After routers become adjacent,
> > the flooding process
> > starts. What I have noticed is that right after
> > routers become
> > adjacent, they create a new router LSA and add one
> > to the sequence
> > number. (The DR also sends out a network LSA.)
> >
> > My question is this: Does each router create this
> > new instance of the
> > LSA to trigger the flooding process itself or is
> > there some other reason
> >
> > why a "new" LSA is created? *Why not just send
> out
> > the original LSA to
> > begin the flooding process?* Doesn't sending out
> a
> > new LSA cause
> > routers to recalculate their routing tables when,
> in
> > fact, they just
> > calculated them moments ago when they became
> > adjacent using the original
> >
> > LSA?
> >
> > I understand the need for the flooding process. I
> > don't understand the
> > need for a new LSA.
> >
> > Thanks in advance,
> >
> > Scott Chapin
> >
> >
> >
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