[c-nsp] Cisco 7206VXR as ATM switch

[Bob Tinkelman]

> Well, with frame-relay, you can just do dlci-switching.

> Thats a feature that has been around for as long as I can remember --
> perhaps 7 or 8 years.

> http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_configuration_guide_chapter09186a0080087d01.html#wp1002491

> frame-relay switching

> int s0/0
>   frame-relay intf-type [dce | dte | nni]
>   frame-relay route in-dlci interface out-interface-type out-interface-number out-dlci


Right.  I actually remember when that enhancement was added,
though not specifically what release it was.


I probably should have used dlci-switching on the router that's
currently bridging two F/R PVCs.  I'm not sure why I didn't.  It
was a very long time ago.  Maybe I wanted to keep the config
similar to the other router that was doing FR-to-Ethernet bridging
on the other end of the PVC.

It may not have been clear that (in my example) I had a PVC between
two routers, with one router bridging the PVC to Ethernet and the
other router bridging the PVC to a PVC on another f/r circuit.

So, I guess my choices are:

    o	Leave things as they are:
	F/R protocol on all circuits
	bridging between PVC and Ethernet on Router A
	bridging between PVCs on Router B

    o	Leave everything as-is, except
	replace: bridging between PVCs on Router B
	with:    dlci-switching between PVCs on Router B

    o	Change everything:
	ATM protocol on the inter-switch T3
	level 2 switching between ATM PVCs on Router A
	level 2 switching ATM-to-Ethernet on Router B
   
Can you think of any obvious reason for one of these to be
better than the others?

- Bob




> On Wed, 1 Jun 2005, Bob Tinkelman wrote:

> >
> >> The feature you want is
> >> http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s27/fslocal.htm
> >
> > Hmmm.  This is a feature I've never used before.
> >
> > I have a few routers which have been configured, forever,
> > to use frame-relay encapsulation on inter-router DS3s and
> > to bridge PVCs to each other or to Ethernet sub-interfaces.
> >
> > On one router I might have something like this:
> >
> > | bridge irb
> > ...
> > | interface Serial2/0/20:0.151 point-to-point
> > !  description PVC on customer T1
> > |  frame-relay interface-dlci 151
> > |  bridge-group 151
> > ...
> > | interface Serial3/0.151 point-to-point
> > !  description PVC to "other router"
> > |  frame-relay interface-dlci 151
> > |  bridge-group 151
> > ...
> > | bridge 151 protocol ieee
> >
> >
> > And, then on another router:
> >
> > | bridge irb
> > ...
> > | interface Serial3/0.151 point-to-point
> > !  description PVC to "other router"
> > |  frame-relay interface-dlci 151
> > |  bridge-group 151
> > ...
> > | interface GigabitEthernet2/0.151
> > !  description Customer VLAN
> > |  encapsulation isl 151
> > |  bridge-group 151
> > ...
> > | bridge 151 protocol ieee
> >
> >
> > This works fine.
> > Would I be better off using "Layer 2 Local Switching" instead?
> > The referenced document doesn't list F/R-to-Ethernet as supported,
> > only ATM-to-Ethernet.  If that's really not supported, I guess I'd
> > have to reconfigure the T3s to be ATM instead of Frame-Relay.
> >
> > --
> > Bob Tinkelman <bob at tink.com>
> > ISPnet, Inc.    718.464.4747
> >

> --
> Alex Rubenstein, AR97, K2AHR, alex at nac.net, latency, Al Reuben
> Net Access Corporation, 800-NET-ME-36, http://www.nac.net