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repost: Re: WGLC ule-03




I'm forwarding the comments below (extracted, from a longer email from "Bernhard Collini-Nocker" <bnocker@cosy.sbg.ac.at>), since they relate to suggested changes to ULE, resulting from reading during the WGLC.

Gorry Fairhurst
(ipdvb WG Chair)

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1. Figure 12 does not provide clear guidance on the placement of the NPA field when extension headers are present. The placement within the base-header needs to be clarified.


So, section 5. provides the following (more complex) example:
   < --------------------------   SNDU   ------------------------- >
   +---+---------------------------------------------------+--------+
   |D=1| Length | T1 | H1 | T2 | H2 | T3 |       PDU       | CRC-32 |
   +---+---------------------------------------------------+--------+
   < ULE base header >< ext 1 >< ext 2 >

   Figure 12: SNDU Encapsulation with two Extension Headers

> Gorry:
I'd kind of assumed the NPA ALAWAYS was a part of the BASE HEADER, and that
it always is inserted after the first type field, with any extension headers
FOLLOWING the NPA when it is present. So, I guess I had imagined:

    < --------------------------   SNDU   ------------------------- >
     +---+---------------------------------------------------+--------+
     |D=0| Length | T1 | NPA | H1 | T2 | H2 | T3 |    PDU      | CRC-32 |
     +---+---------------------------------------------------+--------+
        <base header>   <*1> <  ext 1  >< ext 2 >

*1 NPA, if present, is always counted as a part of the base header.
>
> Thoughts?

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2. In Section 4.7.5 Fig 8

The Bridge Frame SNDU Encapsulation
- "Receiver Destination Address" should be marked as "NPA Address"

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