On Mon, June 25, 2007 5:23 pm, Skeeve Stevens wrote: > As I said - Possible Stupid Question Alert ;-) > > What I want to do I think is valid, so please keep flames on low! > > I want to literally be able to change a VLAN's number in a path of > switches. > > For example: in a peering point we have half a dozen ISP's sharing a > central switch for some private peering. > > All connections are Trunks so the different ISP's can patch dot1q VLAN's > to each other in whatever way they like. > > The issue is with conflicting VLAN numbers in the switch chain (involving > 3750G, 3550, 3560G, 3524XL) and the trunks to the ISP's themselves. > > So, when there is a conflict, I'd essentially like to 'renumber' the VLAN > and then pass it off up the chain so their isn't a conflict in the path.
Ignoring the technical piece for a minute, this seems to rely on three things: - All the ISPs "playing nice" and telling you / checking with you before they use a new VLAN - You doing the admin to maintain a record of who is using what and generate re-mappings accordingly - You configuring switches to match Now, if all of those are true, why not instead ask the ISPs to just ask for a new VLAN when they want one, at which point they get assigned a new one that's global to the exchange point? You update the database, and update the switch config to permit this VLAN only on the "core"-facing trunk ports, and the trunks connecting to the ISPs who want to peer. Seems to me to have the exact same level of interaction with the ISPs, record-keeping, and switch config, without having to come up with anything hairy - and has the bonus that ISPs *can't* inject traffic on "wrong" VLANs when they "forgot" to ask you, as their trunks are locked down. You could probably even automate the whole thing through a web front end and let the ISPs effectively self-provision their own interconnects. Regards, Tim. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
