Tangent for B-LLI (was Re: Comments on ipv6nd-02.txt )

[Grenville Armitage <[e-mail]>]

Bryan,

	[..]

I thought we'd gone over this a year or so ago :-)

>>For example one protocol may use multiple data plane encapsulations (e.g.
>>a Classical IP which uses both LLC/SNAP and "null" encapsulated VCs).
>>The same data plane encapsulation may be used by different protocols
>>(e.g. Classical IP, NHRP, MPOA, LANE V2.0, etc may all use LLC/SNAP
>>encapsulation). As the mapping is many to many the BLLI just doesn't do a
>>good job of identifying signalling user entities. 

I don't think your conclusion in this example is justifiable. The
B-LLI does exactly what it is required to do - identify the AAL User
that will take AAL_SDUs immediately after AAL reassembly.

For Classical IP there can be two types of AAL Users - an IP layer
itself ("null" encapsulation), or an LLC entity (further demuxing
arriving AAL_SDUs based on the LLC/SNAP header).

If an LLC entity is identified as the immediate AAL User to
which AAL_SDUs are passed, and there was no additional B-LLI
or B-HLI field in the call that pre-defined the ultimate
destination of the AAL_SDU's contents, then the LLC entity does
the demuxing of IP, NHRP, LANE, MARS, packets. The various
higher layer protocols are then simply clients of the LLC
entity, and are insulated from the LLC entities interactions
with the AAL layer and UNI instance. I think the B-LLI does
exactly what is needed for identifying 'signalling user entities'.

cheers,
gja
_________________________________________________________________________
Grenville Armitage                               [e-mail]
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