From: Godswill Oletu (oletu@inbox.lv)
Date: Sun Jul 02 2006 - 10:37:56 ART
Sami,
P2MP-Nonbroadcast as you can see from the name is a hybrid solution, it
combines the best of both P2MP & Nonbroadcast Interface types.
P2MP-Nonbroadcast Interfaces Advantages:
* Generate /32 host routes for your spokes (this was taken from P2MP
interface type).
*Uses unicast instead of multicast Hellos (this was taken from the
nonbroadcast interface type).
*The use of multicast means, neighbor statements are needed. (taken from
nonbroadcast interface type)
*No need for DR/BDR elections (taken from P2MP interface types).
Though there are many Task that will point to P2MP-Nonbroadcast, these are
few:
1. Configure OSPF between your Frame relay Routers, ensure that your frame
spoke reachability is facilitated via a dynamic routing protocol,
your solution must use unicast hellos.
2. Do not use dynamic inverse-arp, do not configure mapping between frame
relay spokes, do not use static routes, but enabled IP
reachability between your frame spokes, your solution must ensure that
other OSPF enabled routers apart from R1, R2 & R3 do not intercept
your OSPF communication.
3. Configure OSPF between R1, R2 & R3 with R1 as the hub, do not elect
DR/BDR & do not use multicast hellos on this segment.
4. Configure OSPF between R1, R2 & R3, your solution may use unicast hellos,
but it may not rely on OSPF interface priority to function.
5. Configure OSPF between R5, R1 & R2; ensure that a 'show ip ospf neighbor'
& 'debug ip ospf hello' on R5 have outputs similar to the following:
Rack1R5#sh ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
150.1.2.2 0 FULL/ - 00:01:49 128.1.125.2 Serial0/0
150.1.1.1 0 FULL/ - 00:01:49 128.1.125.1 Serial0/0
Rack1R5#
Rack1R5#
Rack1R5#debug ip ospf hello
OSPF hello events debugging is on
Rack1R5#
*Mar 1 00:46:34.471: OSPF: Send hello to 128.1.125.2 area 0 on Serial0/0
from 128.1.125.5
*Mar 1 00:46:34.471: OSPF: Send hello to 128.1.125.1 area 0 on Serial0/0
from 128.1.125.5
Rack1R5#
You see that, there are good ways of pointing you towards using
P2MP-Nonbroadcast OSPF interface type and there are still 'evil' ways of
doing it, but once you understand all the various OSPF interface types and
how they affect your environment, you can see through any 'trick' in the
wording of the Task ahead of time. This is why it is very important that, at
least before you configure your Frame Relay Section, skip ahead and read the
OSPF section, else you might find yourself coming back to tear down &
reconfiguring your frame relay for things to work correctly.
Note that, you can configure any OSPF interface type on any media type, your
task will direct you which way to go. Eg, Ethernet supports broadcast, but
your task could be worded in such a way that, non-broadcast or other OSPF
network types might be the only appropriate network type to be configured.
This also goes for frame relay physical interface, which is by default
non-broadcast, but can be configured to support OSPF broadcast or any other
OSPF network type.
HTH
Godswill Oletu
CCIE #16464.
----- Original Message -----
From: "Sami" <sy1977@gmail.com>
To: "Victor Cappuccio" <cvictor@protokolgroup.com>
Cc: "ccielab" <ccielab@groupstudy.com>
Sent: Sunday, July 02, 2006 6:13 AM
Subject: Re: OSPF
> Thanks Victor , use P-2-MP non-brodcast where broadcast is not
> supported...we need neighbour command also to make it work.. right ?
>
>
> On 7/2/06, Victor Cappuccio <cvictor@protokolgroup.com> wrote:
> >
> > For Example when you have a Hub and Spoke topology in a Frame-relay
> > Topology, and in the Frame-relay Could Broadcast is not supported
> >
> > The network type ospf OSPF does not depends on the Physical L2
Interface,
> > (OSI Modularity), cool right?
> >
> > HTH
> > Vmctor.-
> >
> >
> > -----Mensaje original-----
> > De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de
Sami
> > Enviado el: Domingo, 02 de Julio de 2006 05:45 a.m.
> > Para: ccielab
> > Asunto: OSPF
> >
> > Group,
> >
> > Couldn't understand in which scenario do we need to use
> > point-to-multipoint
> > non braodcast. FR interface by default is non-braodcast mode.
> >
> > Appreciate if some one can shed some light on this ?
> >
> > Thanks
> >
> > _______________________________________________________________________
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>
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