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Re: IE Lab15 Task 5.21 posted 07/12/2005
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Arun

IE refers to Internetwork Expert workbook. Thanks for sharing the same point
of view.

Amit
----- Original Message ----- 
From: "Arun Arumuganainar" <aarumuga@xxxxxxxxxxx>
To: "Amit Jain" <netsteps@xxxxxxxxxxxxxx>; <silamoni@xxxxxxxxx>
Cc: <ccielab@xxxxxxxxxxxxxx>
Sent: Tuesday, July 12, 2005 1:19 PM
Subject: Re: IE Lab15 Task 5.21


> Ok I see !!! I think I misunderstood your question.
>
> Your question is to prevent sending hello packets to any one hooking on to
> this topology !!!
>
> Yes definitely you have a choice of using Point to Multipoint & non
> broadcast and NBMA network . This is so because since this is 2 router
> frame-relay setup. So the question of Full mesh and partial mesh does not
> arise . Things will absolutely work fine with both modes .
>
> As for as ISDN network is concerned . The media itself is a point to point
> media . Question of any body hooking on to your network does not arise at
> all !!!So changing the Network type is ir-relevant here.
>
> Might be solution could be wrong !!! You can take this with the author of
> book for correction in its next edition !!!
>
> By the way what is IE LAB 15  ( are you referring to IP EXPERT  work
book )
>
> Thanks and Regards
> Arun
> ----- Original Message -----
> From: "Amit Jain" <netsteps@xxxxxxxxxxxxxx>
> To: "Arun Kumar Arumuganainar" <aarumuga@xxxxxxxxxxx>;
<silamoni@xxxxxxxxx>
> Cc: <ccielab@xxxxxxxxxxxxxx>
> Sent: Monday, July 11, 2005 11:59 AM
> Subject: Re: IE Lab15 Task 5.21
>
>
> > 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@xxxxxxxxxxx>
> > To: <silamoni@xxxxxxxxx>
> > Cc: <ccielab@xxxxxxxxxxxxxx>
> > 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@xxxxxxxxx>
> > > >Reply-To: Sila Moni <silamoni@xxxxxxxxx>
> > > >To: Amit Jain <netsteps@xxxxxxxxxxxxxx>,   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@xxxxxxxxxxxxxx> 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
> > > > >
> > > > >
> > >
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