[c-nsp] Possible Stupid Questions Alert - Combining VLAN's

[Jeff Fitzwater]

Try this...

    If you are only dealing with native vlans and not 802.1q vlans, then 
you could connect say port 1 vlan 100 native on one switch to port 2  
vlan  650 on a different switch.  So in this case all vlan 100 frames 
become vlan 650.  Now the catch.  PVST does not like different vlans 
talking to each other, so this will only work if STP is disabled in your 
net.  Also disable CDP on these ports. 

If I understand your issue correctly this should work.

We do not use STP here at all, and we must connect CISCO devices to 
older 3COM devices which only support management on vlan 1.  So each of 
our subnets are assigned different native VLANS which connect to vlan 1 
of downstream 3com device. All the other tagged vlans are carried in the 
trunks normally.

Jeff Fitzwater
OIT Network Systems
Princeton University


Skeeve Stevens wrote:
> Excuse the 5 or so typos in this post which makes it looks like I am
> challenged by the English language... it is 2.32am here ;-)
>
> ...Skeeve
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Skeeve Stevens
> Sent: Tuesday, 26 June 2007 2:23 AM
> To: 'Cisco-nsp'
> Subject: [c-nsp] Possible Stupid Questions Alert - Combining VLAN's
>
>
> 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.
>
> Ideally.
>
> ISP - uses 100
> Sends up trunk into shared switch
> Switch turns vlan 100 into vlan 650 and then sends out link to upstream
> switch and it is forever 650.
>
> Or something like that.
>
> I realise I could just burn 2 ports and put a x-over cable between them, but
> it seems such a waste.
>
> It would also be done on a router, but we don't have that kit available.
>
> I'm ready for useful comments and a share of ridicule.
>
> For those with a massive amount of money who can buy anything their like and
> may respond 'just by a 6509', please remember that not all of us have
> massive amounts of unlimited funding to $100k on a 10G interface for a GSR
> when 100k might be out yearly budget! ;-)
>
> .Skeeve
>
>
>  
> --
> Skeeve Stevens, RHCE
> skeeve at skeeve.org / www.skeeve.org
> Cell +61 (0)414 753 383 / skype://skeeve
>
> eintellego - skeeve at eintellego.net - www.eintellego.net 
> --
> I'm a groove licked love child king of the verse 
> Si vis pacem, para bellum
>
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>