[c-nsp] Bridging ATM on 7206?

[Matthew Crocker]

Nathan,

  It sounds like what you want to do should be possible.  I'm not sure  
if the 7206 can do it or not.   I'm pretty sure a Redback SE-400 can  
do it.

  You need to unwrap the layers of the onion...

  Build a Bridge group on the 7206 and attach each PVC to it.  That  
should create one big layer 2 'switch' which should be transparent to  
the VLAN tags on the PVCs.

  You now need to figure out how to get routed interfaces on the 7206  
attaches to the bridge group.  You could do that with BVIs or you  
could attach G0/1 to the bridge-group and then put a cross connect  
cable into G0/2 and create the VLAN interfaces on G0/2

something like

  bridge 1 protocol vlan-bridge
  bridge irb

interface ATM1/0.50
   no ip address
   pvc 50/50
	encapsulation aal5snap
   bridge-group 1

interface ATM1/0.51
   no ip address
   pvc 51/51
     encapsulation aal5snap
   bridge-group 1

  [...]

interface bvi 1.6
    bridge 1 route ip
    encapsulation dot1q 6
    ip address 6.6.6.6 255.255.255.0

interface bvi 1.7
    bridge 1 route ip
    encapsulation dot1q 7
    ip vrf PRIVATE_IP
    ip address 7.7.7.7 255.255.255.0


I have no idea if this is even close to a working config but it is the  
way I would think it should work.

On May 20, 2008, at 11:18 AM, Nathan wrote:

> Hi,
>
> I have a 7206 G1 running 12.3(21) with a PA-A3 interface. The ATM
> interface has sub-interfaces, aal5snap encapsulated, each one of which
> corresponds to one PVC and to one IP network (30 or /31 usually),
> either public or in a VRF. I do not control the other end of the fiber
> link. The other end of each PVC is usually some device that translates
> between AAL5SNAP and Ethernet, connected to some customer-owned
> equipement.
>
> It seems that VLAN tags received on the Ethernet are encapsulated into
> AAL5SNAP, so the customer should be able to configure 802.1q trunking
> on the ethernet.
>
> Question 1: can I bridge together two PVCs so that the ATM packets
> that come in on one PVC go right out again on the other without being
> de-encapsulated, or at least no layer-2 changes?
>
> Question 2: can I set up something that permits me to distinguish
> VLANs on the vlan-into-aal5snap-encapsulated PVCs, seeing each PVC as
> a 802.1q trunk? I've found LANE, I've found "atm pvc vcd  vpi  vci",
> but I don't see how to tie it all together, especially if I want to
> put each VLAN in a separate VRF.
>
> Basically what I want to do is have several PVCs, each containing a
> 802.1q trunk, and bridge them together, something like this:
>
> - vlan 5 on PVCs 50/50, 50/51, 50/52 together into a single layer 2
> that has no IP address on my 7206
> - vlan 6 on PVCs 50/50, 50/51, 50/52 together into a single layer 2
> that has a public IP address on my 7206
> - vlan 7 on PVCs 50/50, 50/51, 50/52 together into a single layer 2
> that has a private IP address in a VRF on my 7206
>
> so that the network behaves as if the several customer devices on the
> several PVCs were all connected to a simple switch.
>
> Feasible? I'll take partial solutions too . . .
>
> -- 
> Thanks
> Nathan
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