From: Amit Jain (netsteps@rediffmail.com)
Date: Mon Jul 11 2005 - 03:29:15 GMT-3
Thanks Arun, but still I cannot relate your answer to my questions. In my
Diagram
R3 ----frame-relay----R5 ------isdn-------R4
Do you call this hub and spoke, if they are connected together through
different WAN topology??
R3 and R5 are on non-broadcast default mode for which neighbor statement is
configured.
R5 and R4 are on point-to-point mode as what i seee from "sh ip ospf inter
bri0/0"
Ques asked to prevent hello packets to anyone hooking on to this topology.
Sol says that configure point-to-multipoint non-broadcast on all the
routers.
My Ques : Why to configure point-to-multipoint non-broadcast when the
default network type between R3 and R5 is non-br and sending unicast (so
nobody can hook on this segment and see hello) AND
Why to configure point-to-multipoint non-broadcast between R5 and R4 when
default network type point-to-point will prevent leaking of hellos, as the
hellos will only go to other side.
What am I missing?
AMit
----- Original Message -----
From: "Arun Kumar Arumuganainar" <aarumuga@hotmail.com>
To: <silamoni@yahoo.com>
Cc: <ccielab@groupstudy.com>
Sent: Sunday, July 10, 2005 5:14 PM
Subject: Re: IE Lab15 Task 5.21
> For Fram Relay Networks , Default Mode in Frame Relay Network is NBMA .
> But this will work only with Fully Meshed network .In Hub and Spoke
> topology full connectivity can not be achived . Spoke routers will only
> be able to ping Hub router and none of the other spoke routers.
>
> Note :In the above scenario OSPF neighborship will get established .
> Routing table will get populated as normal . But however , connectivity
> alone will not be there across the Spokes .This Problem will also be seen
> in Partially meshed networks as well .
>
> By making the Network type Point to Multipoint you can over come this
> problem . Actually if you inspect the routing table on the point to
> Multipoint network , you will be able to observe host route ( Route with
> /32 Bit mask ) for all connected IP address . This will enable routing
> possible between spokes !!!
>
> Pls. Note : You could add broadcast keyword appended to point to
> Multipoint . In case you are not allowed to configure broadcast key word
> then you will have manually configure neighbour statement . This will
> enable OSPF packets to unicasted over the FR Cloud .
>
> Hope this helps.
>
> Thanks and Regards
> Arun
>
> >From: Sila Moni <silamoni@yahoo.com>
> >Reply-To: Sila Moni <silamoni@yahoo.com>
> >To: Amit Jain <netsteps@rediffmail.com>, Group Study <>
> >Subject: Re: IE Lab15 Task 5.21
> >Date: Sat, 9 Jul 2005 05:52:29 -0700 (PDT)
> >
> >There are two issues that I see from this scenario.
> >
> >1. Typically, you would use the neighbor statement on
> >the hub. Since it is on R3 (spoke), it will create
> >some problems. Are you allowed to put the neighbor
> >statement on R4 as well?
> >
> >2. P-T-M non-broadcast is used in NBMA with virtual
> >circuits of differing speeds (e.g. ISDN and FR).
> >Here, assigning cost to the neighbor is optional.
> >
> >
> >--- Amit Jain <netsteps@rediffmail.com> wrote:
> >
> > > Hi
> > >
> > > In the task, R3 and R5 are connected through frame
> > > relay and R4 and R5 through
> > > ISDN
> > >
> > > R3
> > > -
> > > -
> > > - FR -
> > > -
> > >
> > > R4 - -ISDN - - R5
> > >
> > > Now the ospf area 345 is running on FR and ISDN
> > > links and network type
> > > non-broadcast between R3 and R5, with neighbor
> > > command on R3.
> > > Task requirement is to configure all adjacencies in
> > > area 345 in such a manner
> > > that other devices on segment cannot recieve OSPF
> > > hello packets.
> > > The solution given is that the network type on ISDN
> > > and FR segment be changed
> > > to point-to-multipoint (with ofcourse neighbor
> > > statements)
> > >
> > > My ques is why we need to change it to
> > > point-to-multpoint from non-broadcast
> > > on FR segment ? When the netwrk type is
> > > non-broadcast we are sending packets
> > > as unicast only, so why specifically change to
> > > p-to-multipoint ?? (Only
> > > difference will be no DR/BDR elec and host route)
> > >
> > > Also the ISDN segment is network type point-to-point
> > > so anyways the hello
> > > packets will only go to the other side ?? What am i
> > > missing.
> > >
> > > Could not get the answer from IE website posts.
> > >
> > > Thanks
> > > Amit Jain
> > >
> > >
> >_______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> > >
> >
> >
> >
> >
> >____________________________________________________
> >Sell on Yahoo! Auctions no fees. Bid on great items.
> >http://auctions.yahoo.com/
> >
> >_______________________________________________________________________
> >Subscription information may be found at:
> >http://www.groupstudy.com/list/CCIELab.html
>
> ------------------------------------------------------------------------
>
> Looking for a date? Meet interesting singles like you Sign up with
> Match.com
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sun Sep 04 2005 - 17:00:29 GMT-3