From: Scott Morris (swm@emanon.com)
Date: Wed Sep 22 2004 - 14:41:31 GMT-3
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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