Subject: How to announce ethernet capabilities in GMPLS

From: Freek Dijkstra <[email-masked]>
Date: Wed, 03 May 2006 17:46:05 +0200

Hi,

I have a question about GMPLS.

My interest is mostly scientific in nature; and after reading a few
RFC's and internet drafts, I still found no satisfying answer. I may
have overlooked it.

How would you specify the encoding type for a link with IEEE 802.1q VLAN
tags versus a link which can not do that?
And related, how to distinguish between WAN PHY and LAN PHY encoding?

Imagine a small network with 3 or 4 layer 2 switches, with all
interfaces connected to one central photonic cross connect (MEMS
device). In such a case, it is useful to know the above details.

If I'm correct, a Layer 2 switch announces the capabilities of each
interface using a link state advertisement (LSA).

A LSA seems to contain at least
- "LSP encoding type" and
- "switching type".

In all cases, the parameters seem to be "Ethernet" and "L2SC" respectively.

At least draft-papadimitriou-enhanced-lsps-04 explictly says that WAN
PHY and LAN PHY both fall in the Ethernet "LSP Encoding Type".

draft-dimitri-gels-framework-00 seems to suggest that perhaps new
encoding types must be invented. I take it that I misunderstood, and
this will be defined in the "Switching Capability-Specific Information"
part of the LSA.

I tried looking, and Adrian's excellent Internet and it's protocols
lists that the "Switching Capability-Specific Information" for L2SC
only lists "minimum bandwidth" and "MTU".

Am I correct that the GELS working group will look into extensions for
this purpose? I'm currently not interested (yet) in the specific
details, but mostly in the general idea here. Is there by any chance a
list of already defined "Switching Capability-Specific Information"
parameters for other layers? Perhaps a list of internet drafts to go
through.

I might be wrong here somewhere -- somehow WAN/LAN PHY and IEEE 802.1q
VLAN or not capable seem other type of parameters to me then "MTU"
(which is currently defined for L2SC). If so -- what am I missing?

Regards,
Freek

---

From: <[email-masked]>
Date: Mon, 8 May 2006 21:13:14 +0200

> 
> I'm currently mostly interested in the former case.
> Am I correct that this would typically involve two LSPs at the link
> layer (L2 switch to PXC and PXC to anoother L2 switch) and a third LSP
> at the ethernet layer.
> 
> 

If I understand your setup correctly (switch <--> pxc <--> switch) this
would be one LSP between the switches and through (switched by) the PXC.
This LSP instantiates a 'link' between two ports on the Ethernet
switches.

/Eduard