[ednog] Using MPLS to replace layer 2 trunking
vcelindro at northwestern.edu
Sat Jul 30 00:44:08 EDT 2005
> We've been doing it for about a year, both layer 2 and layer
> 3 MPLS VPNs. We prefer to use layer 3 where we can and use
> layer 2 where we must. Which right now Layer 2 is used only
> for two or three legacy VLANs and cross core backhaul for
> Wireless to authentication boxes in a Data Center.
We are planning to use this for our quarantine networks.
> The 6500/7600 only supports Port based EoMPLS or
> Pseudo-Wires, unless you have OSMs. We are pushing (starting
> over year ago) for the next-gen PFC to support this, but that
> is still a little ways off. There is a way to work around
> this though, a loop back cable between two GigE ports. one
> port is configured as a psudo wire Xconnect and the other as
> a trunk port. Do this on both the 6509s in your diagram
> below and you have a virtualised trunk between them. (Yes it
> is a Hack!!! But it works!)
I talked to a Cisco Engineer briefly about this awhile ago and I recall him
saying that I would have to use a physical loopback, but didn't catch the
details, since I figured it was well documented somewhere.;)
I called the tac about this and mentioned the loopback, they of course had
no idea about what I was talking about, go figure. I was hoping someone
would respond with the specifics of the hack, as you said it works.
> The only way to do this is to have a loop-back per VLAN or use OSMs.
There really aren't any OSMs that appeal to us on a campus environment. I
guess we'll also start pushing cisco for this func. In the next-gen
More information about the ednog