From: James (james@towardex.com)
Date: Mon Jun 28 2004 - 13:55:53 GMT-3
I always avoid gre tunnels if at all possible. using gre tunnels will most likely
transit traffic thru the tunnel, which will hog the router CPU and give you poor
throughput performance when you start pushing real traffic. Yes, it may certainly
be doable for lab situation, and it's certainly good idea to try it out yourself,
but in real-world application, i fail to see the usefulness of transiting traffic
to the backbone thru a gre tunnel. virtual-link sounds better of idea to be used.
you can use tunnel to do OSPF, and use native path for actual traffic to take, but
that kind of defeats the purpose of having an IGP in the first place and what a
black magic mess that will be :) virtual-link will use real native path to push
the transiting traffic.
my 0.02
-J
On Mon, Jun 28, 2004 at 11:12:34AM -0400, ccie2be wrote:
> Hi guys,
>
> What's the advantage or disadvantage of using a virtual link to connect a
> discontinuous ospf backbone area vs using a tunnel to do the same thing?
>
> Besides the authentications available with a virtual link, are there any other
> differences?
>
> Also, let's assume I wanted to use a tunnel in the following scenario:
>
> Area0 --- s0 Rx E0 --- Area xy --- fa0/1 Ry s1 --- Area0
>
>
> Rx and Ry share a common ethernet subnet and each also has a loopback0
> interface.
>
> What should the endpoints of the tunnel be?
>
> Should any pair of endpoints work as long as they're consistent on both Rx and
> Ry? Why yes or no?
>
> Does it matter what area the physical or loopback interfaces endpoints of the
> tunnel are assigned to?
>
> I know that when the loopback interfaces are put in area 0 and the ip addr of
> the tunnel itself is assigned to area 0, this config works. But, I tried
> other which didn't work but I don't understand why.
>
> Could someone explain why that is?
>
> TIA, Tim
>
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-- James Jun TowardEX Technologies, Inc. Technical Lead Network Design, Consulting, IT Outsourcing james@towardex.com Boston-based Colocation & Bandwidth Services cell: 1(978)-394-2867 web: http://www.towardex.com , noc: www.twdx.net
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