From: Hossam (sam6626@yahoo.com)
Date: Sat Jan 17 2004 - 08:09:35 GMT-3
Yasser,
What happens with you is correct. ISIS does't support HUB and Spoke Topology. For ISIS to work correctly over NMBA networks you need a FULL mesh.
Other wise u go for a point-point mode.
http://www.cisco.com/en/US/tech/tk365/tk381/technologies_tech_note09186a008009445a.shtml
Thanks
SAM
Yasser Abdullah <yasser@alharbitelecom.com> wrote:
I was testing ISIS over FR HUB & 3 spokes. Spokes are adjacent only with
the hub and can see the routes advertised by the hub (I can't see other
spokes in the IS neighbors table). The hub is also the DIS and has all
routes in its routing table.
The problem is routes advertised by spokes are in the db of other spokes
but not in the routing table. Every time I reset the ISIS process, the
routes will appear for a few seconds and then disappears.
I tried debugging but could not see any errors. I changed it to a full
mesh topology and it works fine.
Is this an expected behavior? why are the routes in the DB but not the
RT ?
Thank,
Yasser
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Bob Sinclair
Sent: Friday, January 16, 2004 6:30 PM
To: Hossam; ccielab@groupstudy.com
Subject: Re: ISIS over NMBA
Hossam,
You are right on regarding ISIS over Frame-Relay. All routers need to
form
adjacencies with all others on the link, and this cannot happen between
spokes. So normally you will want to use P-P subinterfaces, or
Multipoint
with a single neighbor.
You might be able to get a multipoint hub to work, if the spokes are
different circuit types: what if the hub is L1/L2, one spoke is L1 and
the
other spoke is L2? Then the spokes would not need an adjacency.
hmmmm..
Bob Sinclair
CCIE #10427, CISSP, MCSE
www.netmasterclass.net
----- Original Message -----
From: "Hossam"
To:
Sent: Friday, January 16, 2004 9:13 AM
Subject: ISIS over NMBA
> Guys,
> Theoriticaly, i know that the ISIS has only two supported network
types
"Point - Point" and Broadcast Multiple Access. I know we need to go for
the
point to point option with all FR interfaces.
>
> But i tried configuring ISIS over NMBA (Point to multipoint FR
interface)
over a link between two routers only. And it worked fine. CNLS neihbour
were
up. Routing tables looked ok.
>
> So i thought i have to take one step further and try ISIS over NMBA
with a
HUB and two spokes. Strangly, the CLNS neighbors were up between the
three
routers. The HUB routing table was ok too. But the spokes did't have the
full routing table.
>
> I think this is realated to that ISIS unlike OSPF needs to build up
links
between all routers over the Multiple access network and NOT only the
Designated router. I think if i went to a FULL Mesh instead of HUB and
spoke
it will work? is't it??
>
> Is my understanding ok?? do i miss anything?
> Is there any turn arrounds to get the ISIS over a HUB and spoke layout
over NMBA to work??
>
>
> Thanks
> SAM
>
>
> ---------------------------------
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>
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