From: Wang Dehong-DWANG1 (Dehong.Wang@motorola.com)
Date: Wed Sep 22 2004 - 15:38:08 GMT-3
Scott
Thanks for the response and it really make sense.. Don't have a lab right now and can not try it now any more. I did try to play with AD and metrics but for some reasons I failed to make it work. Since only OSPF is used, I thought that putting "ip ospf cost 30000" under both tunnels might work, but it seemed R3 think it is directly connected net and use 0/0(could be wrong, can not remember the detail logs any more). Should this be the way to manipulate the metric?
R3 Router:
========
int tunne1
ip ospf cost 30000 <=== play with cost
R1 Router:
=========
int tunn 1
ip ospf cost 30000
Thanks again.
-----Original Message-----
From: Scott Morris [mailto:swm@emanon.com]
Sent: Wednesday, September 22, 2004 12:42 PM
To: Wang Dehong-DWANG1; ccielab@groupstudy.com
Subject: RE: recursive routing with a tunnel
You do anything that is necessary to make sure that even after the tunnel is up (and whatever new routing peering is up) the route to the "tunnel destination" is NOT going to be preferred to come through the tunnel.
If the routing protocol is the same in and out of the tunnel, metrics may be used... If you have two different routing protocols, then AD is a good choice to use. Distribution lists may also be something to consider making sure that the 'tunnel destination' route doesn't come into the routing protocol on the tunnel.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP, JNCIP, et al. IPExpert CCIE Program Manager IPExpert Sr. Technical Instructor swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Wang Dehong-DWANG1
Sent: Wednesday, September 22, 2004 12:30 PM
To: ccielab@groupstudy.com
Subject: recursive routing with a tunnel
I knew that this has been posted before.. but would like to ask it again.. Here is the scenario.
R4 ------- (area 4 ) -----R3---( serial link, area 2 )---------- R2--------(serial link, area 3) ----------- R1------- (area 0)
R3 serial link IP: 172.16.2.3
R1 serial link IP: 172.16.3.1
R3 Router:
========
int tunne1
ip add 172.16.15.3 255.255.255.0
tunnel destination 172.16.3.1
tunnel source 172.16.2.3
R1 Router:
=========
int tunn 1
ip add 172.16.15.1 255.255.255.0
tunn destination 172.16.2.3
tunn source 172.16.3.1
R1 connects to area 0, a virtual link was also created between R1 and R2 to learn the routes from area 2. I also built a tunnel between R3 and R1 through area 0 so all the routes in area 4 can be learned as well. I created additional interface on both R1 and R3 and then put them under ospf area 0. It hit the recursive routing.. R3 sees a directly route through 172.16.15.0 subnets and then started to delete routes learned through serial interface, which brought the tunnel interface down..
I am thinking of manipulating the distance which make some routes prefer serial link and some use tunnel, but do not know exactly how.. Your helps are highly appreciated..
thanks in advance.
- Dehong
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