From: Scott Vermillion (scott_ccie_list@it-ag.com)
Date: Mon Nov 05 2007 - 15:00:20 ART
Hey Alex,
Well, is there more to the task since both R4 and SW1 are attached directly
to the backbone? Or is this a segmented backbone type of a task? If the
requirement is that another unnamed ABR attached to Area 47 establish
connectivity to the backbone, you'd need to look at alternatives such as a
GRE tunnel (placed in Area 0), as virtual links require full routing
knowledge in the transit area. This, as I understand it, is due to the fact
that only OSPF traffic (protocol 89) is tunneled over the VL, whereas
payload traffic is sent natively through the transit area. A GRE tunnel
solves this problem if you don't have full routing knowledge. See:
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example0918
6a00801ec9ee.shtml
If it's a segmented backbone task (the more I think about it, the more it
seems that must be what you've described), then again I would think a GRE
tunnel might be the ticket. Sorry but I likely won't have time to lab this
up today, so this is just more thinking out loud than a solid answer...
Regards,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Alex
Steer
Sent: Monday, November 05, 2007 9:47 AM
To: ccielab@groupstudy.com
Subject: ospf virtual-link over totally stubby area
Hi,
I got completely stuck on this question I hoped someone maybe able to help
me
out. The topology is as follows
AREA 0=Router4====area 47=====Switch1=area0
The question was (word for word):-
Configure OSPF area 47 on the Ethernet segment between R4 and SW1
Devices in OSPF area 47 should only receive LSA of type 1, 2 and a default
of
type 3.
To me that says configure Router 4 with "area 47 stub no-summary"
The problem then is that I cant configure a virtual-link to SW1s area0.
Is the answer on router4:-
configure area47 as normal area
configure "default-information orginate always" on router4
configure "area 47 filter-list prefix prefix-list"
ip prefix-list prefix-list permit 0.0.0.0/0 le 32
Can anybody suggest for sure?
Many thanks
Alex
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