From: Tony Olzak (aolzak@xxxxxxxxxxxxxxxxxxx)
Date: Tue Oct 17 2000 - 19:50:53 GMT-3
Mapping is required for spoke-to-spoke communication if you use "ip ospf
network broadcast". If you use "point-to-multipoint", OSPF dynamically
creates routes for each spoke using the hub router as the next hop.
Remember also that if you use a map statement to reach another spoke, you'll
need another one to reach the hub router. Using frame-relay maps disables
inverse arp.
Tony
----- Original Message -----
From: "Andres Zeller" <azeller@uswest.net>
To: "Tony Olzak" <aolzak@buckeye-express.com>
Cc: "Sam Munzani" <sam@munzani.com>; "mannan venkatesan" <venkat_m@ins.com>;
<ccielab@groupstudy.com>
Sent: Tuesday, October 17, 2000 5:22 PM
Subject: Re: OSPF Problem
> I thought the static mapping was only necessary if you do not support
> inverse-arp.
>
> Andres
>
> Tony Olzak wrote:
> >
> > 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,
> > > > >
> > > > >
> > > > >
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:25:27 GMT-3