From: adel habbas (a_ahabbas@hotmail.com)
Date: Mon Dec 09 2002 - 21:10:51 GMT-3
The problem, as Debbie pointed out herself, is that she is unable to
create a virtual link over the nssa area 1. This is in fact not possible
according to RFC 2178
http://www.faqs.org/rfcs/rfc2178.html
see section 3.6
"There are a couple of restrictions on the use of stub areas. Virtual
links cannot be configured through stub areas. In addition, AS
boundary routers cannot be placed internal to stub areas."
NSSA by definition is a stub area.
Additonally, all areas must be connected to the OSPF backbone (area 0)
either physically or logically. Area 0 is used to propogate routes
between other areas.
To sum it all up. The topology would need to be changed in order for all
networks to be reachable from all routers.
SOLUTION: connect r3+r5 via ethernet and configure those directly
connected interface to be in OSPF area 0. As noted in her config r3e0
interface is already in area 0.
ADDITIONAL INFO:
Please refer to Karl Solie's Practical Studies vol 1 pg. 801 for more
information on how to configure virutal links.
Jeff Doyle Routing TCP/IP vol. 1 pg. 481 "Virtual links cannot be
configured within, or transit, a stub area".
Good luck!
A
>From: "Adam Crisp" >Reply-To: "Adam Crisp" >To: "Debbie Westall" ,
>Subject: RE: Ospf stub and NSSA problem >Date: Mon, 9 Dec 2002 22:18:57
-0000 > >Hi Debbie, > >I think the problem here is that you need a
virtual link between R5 and R3 >BUT you need to be aware that you form
virtual links using RouterID's, not >necessarily router loopbacks! > >can
I suggest you try and form the virtual link, by doing the following. >1.
Make the routerID of router3 the serial(FR) interface >2. Make the
routerID of Router4 the ethernet interface. > >you should be able to ping
R3 from R5 and vica versa (router IDs) >it's then simply a matter of
configureing the virtual link between these >routers > >please let me
know how you get on! > >cheers > >Adam > > >-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
>Debbie Westall >Sent: 09 December 2002 20:18 >To: ccielab@groupstudy.com
>Cc: ccielab@groupstudy.com >Subject: Ospf stub and NSSA problem > > >I'm
working on a lab and need alittle help..... > >Here's the diagram: > >
------- ------ > | R1 |------------ | R3 | > ------- ------- > | > | >
------- > | R2 | > ------- > | > | > ------ > | R5 | > ------- > >* There
is frame-relay, fully meshed between R1, R2 & R3., R5 is connected > via
ethernet. >* R1 (all interfaces), area 1 >* R2 (loopback2, s0/0.1and
s0/0.2) - area 1 >* R3 (s0/0.1 & s0/0.2) are in OSPF area 1 >* Area 1 is
an NSSA. >* R3 (interfaces L0, L1, & L2 are area 0), e0/0 is area 3. >*
R5 (Interfaces e0/0, L0) area Area 2. >* Area 2 is a stub network. > >I
don't see routes in R3 to R5, except for the directly connected. And
>vice versa from R5 to R3. In addition, on R5 I have formed a neighbor
>relationship, but have no routing table, except for the directly
>connected. > >I tried setting up a virtual link through Area 1, but it
will not because >Area 1 is an NSSA. > >I don't know what I'm missing. >
>Thanks for any assistance > >Debbie >. >.
>__________________________________________________________________ >To
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