From: Bogdan Sass (bogdan.sass@catc.ro)
Date: Sun Sep 07 2008 - 05:46:12 ART
Hobbs wrote:
> Hi,
>
> Did you ever find a solution to your problem? I did this lab and never
> had that issue...
I did find what seems to be a solution - although I'm still not sure
what caused the problem.
While troubleshooting, I noticed that R2 was trying to replicate
OSPF packets on all interfaces (Virtual-Template, 2xVirtual-Access, and
Multilink). So I removed the "network" command from OSPF, and activated
OSPF only on the multilink interface (using the "ip ospf 1 area 0"
command). And then... everything worked.
R3, on the other hand, was sending updates only on the multilink
interface. Probably because R3 had two physical interfaces, while R2 had
subinterfaces on the same physical link.
As I was saying, I'm still not sure what caused the problem ("no RTR
back link"). I can only assume that OSPF somehow saw that router ID
accessible through the virtual-template interface, which is always down.
Maybe someone more experienced could shed some light on this subject?
Thank you,
-- Bogdan Sass CCAI,CCNP,CCSP,JNCIA-ER Information Systems Security Professional "Curiosity was framed - ignorance killed the cat"> > On Mon, Aug 25, 2008 at 7:33 AM, Bogdan Sass <bogdan.sass@catc.ro > <mailto:bogdan.sass@catc.ro>> wrote: > > I am working on an IE lab (lab 8), and I have the following > topology: > > R2 directly connected to R3, over a multilink interface (MLPPP > over FR). Both advertising their loopback interfaces into OSPF area 0. > > The problem: while R3 sees R2's loopback, R2 doesn't see the > route from R3: > > R3#sh ip ro > 174.1.0.0/24 <http://174.1.0.0/24> is subnetted, 2 subnets > C 174.1.3.0 <http://174.1.3.0> is directly connected, Ethernet0/0 > C 174.1.23.0 <http://174.1.23.0> is directly connected, Multilink1 > 150.1.0.0/16 <http://150.1.0.0/16> is variably subnetted, 2 > subnets, 2 masks > C 150.1.3.0/24 <http://150.1.3.0/24> is directly connected, Loopback0 > O 150.1.2.2/32 <http://150.1.2.2/32> [110/1786] via 174.1.23.2 > <http://174.1.23.2>, 00:01:02, Multilink1 > > R2#sh ip ro > 174.1.0.0/24 <http://174.1.0.0/24> is subnetted, 1 subnets > C 174.1.23.0 <http://174.1.23.0> is directly connected, Multilink1 > 150.1.0.0/24 <http://150.1.0.0/24> is subnetted, 1 subnets > C 150.1.2.0 <http://150.1.2.0> is directly connected, Loopback0 > > A debug ip ospf spf on R2 shows the following: > > *Mar 1 06:03:44.786: Processing link 2, id 150.1.3.3 > <http://150.1.3.3>, link data 174.1.23.2 <http://174.1.23.2>, type 1 > *Mar 1 06:03:44.786: No RTR Back link > > Does anyone know why this happens and how to fix it? I wouldn't > mind so much the loss of one route, but... if the router id is not > accessible, neither are any of the routes distributed by R3... :| > > Thank you, > > -- > Bogdan Sass > CCAI,CCNP,CCSP,JNCIA-ER > Information Systems Security Professional > "Curiosity was framed - ignorance killed the cat" > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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