Re: ARE: [T1X1.5] arbitrary contiguous concatenation question

[Maarten Vissers <mvissers@lucent.com>]

Eric,

Let's discuss this issue during the IETF meeting in London. Being face to face
its easier to illustrate that a STS-3c isn't using 3 physically contiguous
timeslots.

For the standard contiguous concatenation (including STS-3c) there are T1.105
and G.707 defining the timeslots used. But there are no transport plane
documents that define the timeslot allocation for arbitrary concatenation. I.e.
is a STS-3a using physically contiguous timeslots or is it using the same
timeslots a STS-3c would use?
As the gmpls-sonet-sdh document is the first and only standard describing
arbitrary concatenation, interworking is only guaranteed when it is unambiguous
which timeslots are being used.

Regards,

Maarten

"Mannie, Eric" wrote:
> 
> Hello Juergen and Maarten,
> 
> I don't understand the relationship between
> draft-ietf-ccamp-gmpls-sonet-sdh-01.txt and the problem that you are talking
> about.
> 
> In addition, the IETF is not specifying any SDH/SONET interoperability (Not
> at all in the GMPLS scope).
> 
> Also, I am not sure to understand why the abstract (B, A) notation of G.707
> (used to have a clearer specification, and not used (transported) in any
> protocol as far as I know) could imply that contiguous time-slots are not
> contiguous anymore ?
> 
> The "Arbitrary" concatenation that you are speaking about is a contiguous
> concatenation, time-slots are physically contiguous. I don't understand the
> relevance of the SDH (B, A) notation in relationship with SONET in the
> context of the IETF. Anyway, contiguous time-slots will stay physically
> contiguous even if you see an issue with the SDH G.707 (B, A) notation
> applied to SONET.
> 
> Also, "flexible arbitrary concatenation" (whatever it is - everybody seems
> to have a different understanding) is not part of
> draft-ietf-ccamp-gmpls-sonet-sdh-01.txt.
> 
> I guess also that this discussion is relevant for the ITU-T and/or T1X1, not
> for the ccamp mailing list (of the IETF).
> 
> Kind regards,
> 
> Eric
> 
> -----Original Message-----
> From: Heiles Juergen [mailto:Juergen.Heiles@icn.siemens.de]
> Sent: Tuesday, July 24, 2001 4:28 PM
> To: 'Maarten Vissers'; ccamp
> Cc: t1x1.5; q11/15
> Subject: AW: [T1X1.5] arbitrary contiguous concatenation question
> 
> Maarten,
> 
> good point. Lets hear what the supporters of arbitrary concatenation have to
> say.
> 
> Juergen
> 
> > -----Ursprüngliche Nachricht-----
> > Von: Maarten Vissers [mailto:mvissers@lucent.com]
> > Gesendet: Dienstag, 10. Juli 2001 11:14
> > An: ccamp
> > Cc: t1x1.5; q11/15
> > Betreff: [T1X1.5] arbitrary contiguous concatenation question
> >
> >
> > All,
> >
> > draft-ietf-ccamp-gmpls-sonet-sdh-01.txt defines signalling
> > support for arbitrary
> > contiguous concatenation in appendix 3. Looking a bit more
> > into this arbitrary
> > concatenation from the transport plane, I came across a
> > question with respect to
> > the definition of "contiguous STS-1/AU-3 timeslots". Let me
> > introduce this
> > question:
> >
> > Figure 7-25/G.707 (10/2000) lists the AU-3 numbering (within
> > an STM-4) as
> > follows
> >
> >      Time          111
> >      Slot 123456789012123456789
> >
> >       B 123412341234123412341...
> >       A 111122223333111122223...
> >
> > AU-3 timeslots have a TimeSlot number and a (B,A) number,
> > with TS1 associated
> > with (1,1) and TS12 associated with (4,3).
> >
> >       Note - the figure in the pre-published version of G.707
> >       doesn't show the timeslot numbering in a correct manner.
> >
> > and the AU-4 numbering is as follows (figure 7-24/G.707)
> >
> >      Time
> >      Slot 123412341234123412341
> >
> >       B 123412341234123412341...
> >       A 000000000000000000000...
> >
> > An AU-4 [STS-3c] is as such essentially a "non-contiguous"
> > concatenation of
> > AU-3s [STS-1s]; i.e. every 4th AU-3/STS-1 is use; e.g. AU-4
> > (2,0) uses AU-3
> > timeslots 2,6,10 [i.e. (2,1), (2,2), (2,3)].
> >
> >
> > If we define STS-1 contiguous concatenation, which timeslots
> > are then used for
> > e.g. a STS-1-3c:
> >       i)  timeslots (1,1),(2,1) and (3,1) [TS1,TS2,TS3], or
> >       ii) timeslots (1,1), (1,2) and (1,3) [TS1,TS5,TS9]
> >
> > Similarly, for the case of a STS-1-6c do we use:
> >       i)  (1,1), (2,1), (3,1), (4,1), (1,2) and (2,2)
> > [TS1,TS2,TS3,TS4,TS5,TS6] or
> >       ii) (1,1), (2,1), (1,2), (2,2), (1,3) and (2,3)
> > [TS1,TS2,TS5,TS6,TS9,TS10]
> >
> >
> > And which timeslots do we use for e.g. a STS-1-5c?
> >
> >
> > If this detail is not specified, interworking is not possible
> > unless we include
> > the list of timeslots as we do with virtual concatenation
> > (and as discussed for
> > flexible arbitrary concatenation).
> >
> >
> > Regards,
> >
> > Maarten
> >
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