From: ccie2be (ccie2be@nyc.rr.com)
Date: Tue Aug 23 2005 - 09:30:59 GMT-3
This sounds like a recursive tunnel issue.
If you make the ospf metric of the tunnel very high relative to the other
paths for reaching the remote tunnel endpoint, that could solve your
problems.
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Loi,
Choon Ho
Sent: Tuesday, August 23, 2005 8:16 AM
To: ccie2be; ccielab@groupstudy.com
Subject: RE: OSPF Virtual-Link & GRE
Hi,
When I change the GRE tunnel to area 0, it become unstable.
I found out that the tunnel itself giving the intermittent problem.
When I try to ping from one tunnel ip to the other tunnel ip, it also
drop intermittently.
-----Original Message-----
From: ccie2be [mailto:ccie2be@nyc.rr.com]
Sent: Tuesday, August 23, 2005 6:03 PM
To: Loi, Choon Ho; ccielab@groupstudy.com
Subject: RE: OSPF Virtual-Link & GRE
Hi,
Interesting config.
This is what I noticed.
You configured a virtual link between R2 and R5 which extends area 0 to
area 2. Then you configured a gre tunnel from R2 to R3 to extend area 0
to area 3.
That's an interesting way to approach this problem but I don't think
that's the correct way to approach this problem.
When you extend area 0 out to non-backbone area which are not directly
connected to the backbone, there are 2 things I try to keep in mind:
1 A gre tunnel or virtual link (which is in essence a tunnel)
extend
area 0 out to other areas and therefore always should be part of area 0.
In your config, you put your gre tunnel in area 3. If it were in area
0, this might work.
2 You chain virtual links. So, if you added a virtual link between
R5
and R3, that would work.
One other thing to note: If you're not using any type of stub area, you
don't need a gre tunnel - virtual links will work fine. However, if any
of the transits areas are any type of stub area, you must use a gre
tunnel.
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Loi, Choon Ho
Sent: Tuesday, August 23, 2005 5:08 AM
To: ccielab@groupstudy.com
Subject: OSPF Virtual-Link & GRE
Hi,
I lab-up the following Scenario for OSPF:
Area 0 | R2 -----Area 1------- R5 ------Area 2--------R3--------| Area 3
Everything works fine... but, my ping drop intermittently when I try to
ping from Area3 to Area0.
Anything wrong with my configuration?
Thanks.
Following is my configuration:
hostname r2
!
!
interface Loopback0
ip address 192.2.2.2 255.255.255.0
!
interface Tunnel0
ip address 23.23.23.2 255.255.255.248
tunnel source Serial1/1
tunnel destination 172.16.35.1
!
interface Serial1/1
ip address 172.16.25.1 255.255.255.252
encapsulation ppp
router ospf 1
router-id 2.0.0.2
log-adjacency-changes
area 1 virtual-link 5.0.0.5
network 23.23.23.0 0.0.0.7 area 3
network 172.16.25.0 0.0.0.3 area 1
network 192.2.2.0 0.0.0.255 area 0
------------------------------------------------------------------------
--- ! hostname r5interface Loopback0 ip address 100.100.100.100 255.255.255.0 ! interface Loopback1 ip address 5.0.0.5 255.255.255.255
interface Serial0/0 ip address 172.16.25.2 255.255.255.252 encapsulation ppp no fair-queue ! interface Serial0/1 ip address 172.16.35.2 255.255.255.252 encapsulation ppp ! router ospf 1 router-id 5.0.0.5 log-adjacency-changes area 1 virtual-link 2.0.0.2 network 172.16.25.0 0.0.0.3 area 1 network 172.16.35.0 0.0.0.3 area 2 neighbor 5.5.5.2 !
------------------------------------------------------------------------ ------ ! hostname r3
interface Loopback0 ip address 10.10.10.3 255.255.255.255 ! interface Tunnel0 ip address 23.23.23.3 255.255.255.248 tunnel source Serial1/1 tunnel destination 172.16.25.1
interface Serial1/1 ip address 172.16.35.1 255.255.255.252 encapsulation ppp serial restart_delay 0 clockrate 64000
router ospf 1 router-id 3.0.0.3 log-adjacency-changes network 10.10.10.0 0.0.0.255 area 3 network 23.23.23.0 0.0.0.7 area 3 network 172.16.35.0 0.0.0.3 area 2 ------------------------------------------------------------------------ -------------------------------------
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