From: Tony Olzak (aolzak@xxxxxxxxxxxxxxxxxxx)
Date: Tue Oct 17 2000 - 17:10:44 GMT-3
Except that on a true multi-point frame, you don't need map statements if
you use "point-to-multipoint". If you use broadcast you'll need to alter
priorities and place map statements on the spokes.
Tony
----- Original Message -----
From: "Andres Zeller" <azeller@uswest.net>
To: "Sam Munzani" <sam@munzani.com>
Cc: "mannan venkatesan" <venkat_m@ins.com>; <ccielab@groupstudy.com>
Sent: Tuesday, October 17, 2000 12:17 PM
Subject: Re: OSPF Problem
> The OSPF network type is only significant, in that it must be the same
> for all routers participating on a particular link, Whether it is a p2p
> or p2multip.
>
> Andres
>
> Sam Munzani wrote:
> >
> > Comments inline.
> >
> > > Hi,
> > > I was playing in ospf over FR lab and came across an interesting
problem(I
> > > was trying to simulate the problem we had in our client production
> > network).
> > > I configured R1 as hub (sub-ifs) and R2 and R3 as spoke (physical
> > > interface). Here the config,
> > >
> > > R1 :
> > > interface Serial0.1 point-to-point
> > > ip address 10.1.0.1 255.255.0.0
> > > ip ospf network broadcast
> > > frame-relay interface-dlci 100
> >
> > Why are you using "ip ospf network broadcast" on a point-to-point link?
> > Specially in NBMA it's not a good idea. Leave it to default
Point-to-Point.
> > and it will form adjecency with remote end.
> >
> > > !
> > > interface Serial0.2 point-to-point
> > > ip address 10.2.0.1 255.255.0.0
> > > ip ospf network Point-to-multipoint
> > > frame-relay interface-dlci 103
> >
> > Again,
> > If your interface is Point-to-Point why are you using
Point-to-Multipoint in
> > here? Use point-to-point at both ends.
> >
> > > router ospf 10
> > > network 10.0.0.0 0.255.255.255 area 0
> > >
> > > R2 :
> > > interface Serial0
> > > ip address 10.1.0.2 255.255.0.0
> > > encapsulation frame-relay
> > > ip ospf network Point-to-multipoint
> > > frame-relay map ip 10.1.0.1 106
> > >
> > > router ospf 10
> > > network 10.0.0.0 0.255.255.255 area 0
> > >
> > > R3:
> > > interface Serial0
> > > ip address 10.2.0.2 255.255.0.0
> > > encapsulation frame-relay
> > > ip ospf network Point-to-multipoint
> > > frame-relay map ip 10.2.0.1 106
> > >
> > > router ospf 10
> > > network 10.0.0.0 0.255.255.255 area 0
> > >
> > > It worked fine with this config. Then I changed OSPF network type to
> > > "Broadcast" in s0 of R3 and s0.2 of R1. R3 became DR and R1 became
BDR.
> > > After I changed OSPF network type to "Broadcast" in s0.1 of R1 and s0
of
> > R2.
> > > As soon as I entered network type 'broadcast' in R2, the network
broke. I
> > > couldn't access any of the routers for 5 minutes.
> > >
> > > Now 'sh ip ospf nei' command shows,
> > >
> > > R1:
> > > Neighbor ID Pri State Dead Time Address
> > Interface
> > > 10.1.0.2 1 FULL/BDR 00:00:39 10.1.0.2
> > Serial0.1
> > > 10.2.0.2 1 FULL/BDR 00:00:37 10.2.0.2
> > Serial0.2
> > >
> > > R2:
> > > Neighbor ID Pri State Dead Time Address
> > Interface
> > > 10.2.0.1 1 FULL/DR 00:00:31 10.1.0.1
Serial0
> > >
> > > R3:
> > > Neighbor ID Pri State Dead Time Address
> > Interface
> > > 10.2.0.1 1 FULL/DR 00:00:39 10.2.0.1
Serial0
> > >
> > > I know DR and BDR election was going on, but why the network broke?
During
> > > election, routers multicast packets and we have only 3 routers. So,
what
> > > traffic did the routers send here? Can I have multiple OSPF network in
one
> > > broadcast medium? Can someone clarify my questions? Think I am missing
> > > something here.
> > >
> > > Thanks,
> > > Mannan Venkatesan
> > >
> > >
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