Re: Layer 2 Switching Caps LSPs

["Adrian Farrel" <adrian@olddog.co.uk>]

Thanks Dave,

Just one point...

Is there any difference (from the point of view of the network) between a
VLAN with just two sites, and an LSP that uses the (same along the whole
path) VLAN tag to route data?

Clearly there is a difference in hardware with respect to the way that the
hardware is programmed from the control plane.)

Adrian
----- Original Message ----- 
From: "David Allan" <dallan@nortelnetworks.com>
To: "'Adrian Farrel'" <adrian@olddog.co.uk>; "'Shahram Davari'"
<Shahram_Davari@pmc-sierra.com>
Cc: <ccamp@ops.ietf.org>
Sent: Thursday, January 27, 2005 9:37 PM
Subject: RE: Layer 2 Switching Caps LSPs


> Hi Adrian:
>
> Your suggestion is in a way reasonable but with the caveat that in IEEE
> terms, a bridging topology is currently all VLANs (802.1Q single
spanning
> tree) or partitioned into specific ranges (I believe 64 in 802.1s
although I
> do not claim to be an expert).
>
> If the PEs were to implement a bridge function and we were using GMPLS
to
> interconnect them, then the control plane should be identifying either
all
> VLANs (single spanning tree, which I beleive the draft covers by
referring
> simply to Ethernet port) or a VLAN range to be associated with the LSP
> consistent with 802.1s if it is to operate to interconnect bridges
defined
> by the IEEE...
>
> I suspect assuming any other behavior (e.g. LSP for single VLAN tag)
would
> go outside the boundary of what is currently defined...so alignment with
> 802.1s IMO would be a minimum requirement if we are to consider carrying
> VLAN information in GMPLS signalling....
>
> cheers
> Dave
>
> You wrote....
> > Hi,
> >
> > The authors of the draft might like to clarify for the list
> > exactly what data plane operations they are suggesting. To me
> > it seems possible that the draft is proposing VLAN ID
> > *swapping*. But an alternative is that the VLAN ID is used as
> > a label, but that the same label is used for the full length
> > of the LSP.
> >
> > Adrian
>
>
>