The MPLS WG Archive

[ananth.nagarajan@mail.sprint.com]

Shahram,

[deleted]

> It seems that you have confused the "layer above" with the 
> "layer below".
> X over MPLS always requires a Shim header. It is the "layer 
> below" or the
> data-link layer that has different format.
> 

With due respect, I think that's what Yakov meant - if you read 
carefully. in "layer above", he was referring to the layer above the 
transport layer, and saying that the transport layers could be 
different in the case of MPLS.

While i completely agree with Yakov that the theoretical/traditional 
layering concept makes very little sense in the MPLS case, I think what 
Neil refers to when he uses the term "layer" is a "logical separation 
of functionality".  In this sense, it makes perfect sense to  consider 
the functionality of the MPLS data plane as logically separate from the 
control plane.

Yakov, without getting into arguments over terminology,  when we view 
this logical separation, I think Neil's arguments make a lot of sense.

Ananth

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