Subject: [PWOT] draft-anavi-tdmoip-01.txt

From: "Motty Anavi" <[email-masked]>
Date: Mon, 5 Mar 2001 12:22:44 -0500

FYI,
    This draft proposes a simple way of transporting TDM circuits over IP.
It can be found on the IETF web site at:
http://www.ietf.org/internet-drafts/draft-anavi-tdmoip-01.txt

I would appreciate any comments you might have.

-- Cheers, Motty

Motty Anavi               |900 Corporate Dr.
RAD data communication    |Mahwah, NJ 07430
Dir. of Product Management|(201)529-1100x213
e-mail: [email-masked]

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From: "Andrew G. Malis" <[email-masked]>
Date: Tue, 06 Mar 2001 00:25:46 -0500

Motty,

>I would appreciate any comments you might have.

I agree that it's very simple, but it seems to have skimped on many of the 
issues and details that have been discussed previously in 
draft-boyle-sts-ip-00.txt and draft-malis-sonet-ces-mpls-03.txt, such as 
non-synchronous timing recovery, synchronous justification events, outage 
signaling, efficiency, and interactions with Internet traffic engineering.

In addition, AAL1 and AAL2 also make a number of assumptions based upon 
their usage above ATM, such as insured cell sequentiality and particular 
jitter and loss bounds, that need to be made explicit if you attempt to use 
them over IP rather than ATM.  I would be interested in hearing if you are 
aware of their successful use in non-ATM environments.

My final comment is that your text is very unclear regarding the use of 
RTP.  Its use is discussed in section 2, but not in section 5.  Is it used, 
or not?

Cheers,
Andy

========

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From: "Motty Anavi" <[email-masked]>
Date: Tue, 6 Mar 2001 15:18:55 -0500

Hi Andy,
     Thank you for your comments. First of all, let me clarify that the
purpose of the document was to propose a high-level guidelines for a
solution. It did not go in to the technical details.
     Having stated that, we fully intend to go over a much more detailed
technical solution. Our assumption was that it was preferable to present a
high level view and concentrate on the requirements, so that we could
establish a work group charter, and drill down later.

   We're also not assuming any specific infrastructure in place that would
create undue constraints on the implementation of the interworking function.

     As for the specific issues you raised regarding the draft:
1. Clocking issues - While this is not referenced in the draft directly,
non-synchronous timing recovery is can be handled through the clocking
mechanism. Adaptive clocking can be used for that.
2. QoS - As an interworking function, the protocol should allow for the
transporting layer to distinguish and prioritize the TDM traffic over lower
priority traffic. As such, mechanisms allowing prioritization and
differentiation should be supported. We would add a section dealing with QoS
interaction. We shouldn't consider QoS requirement of any underlying layer,
but rather provide a mechanism for that layer to prioritize the time
critical data using it's own mechanisms.
3. AAL1 + AAL2 assumptions - I agree that additional facilities should be
outlined for the exact compensations that are to be made for AAL1 and AAL2
to be more efficient, however, the crux of the matter is the use of a
pre-existing standards infrastructure in interworking function to provide
the basis for a more detailed implementation.
4. Use of RTP - We are not proposing using RTP. The overhead is quite large,
considering we can get the RTP clocking benefits through the existing AAL
structures.

We do consider this draft a good solution and don't consider this just as an
informational draft.

Hopefully, this will clarify our approach to this draft and also serve to
enhance your understanding of TDMoIP.

Thanks again for your comments.

-- Cheers, Motty

> -----Original Message-----
> From: Andrew G. Malis [mailto:[email-masked]]
> Sent: Tuesday, March 06, 2001 12:26 AM
> To: Motty Anavi
> Cc: [email-masked]; Yaakov Stein; Schwarzbauer Hanns Juergen
> Subject: Re: [PWOT] draft-anavi-tdmoip-01.txt
>
>
> Motty,
>

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From: "Andrew G. Malis" <[email-masked]>
Date: Tue, 06 Mar 2001 16:25:16 -0500

Motty,

My primary concerns with AAL1 and AAL2 are just that they were designed 
assuming that they are run over ATM, and thus there are assumptions 
regarding the layer below them that IP/UDP may not meet, at least without 
support from diffserv and perhaps other mechanisms, including 
MPLS.  Compensations for the differences of functionality between ATM and 
IP/UDP need to be made explicit in your draft.

Thanks,
Andy

---------

> > >Dir. of Product Management|(201)529-1100x213

________________________________________________________________________
Andrew G. Malis     [email-masked]     phone:408-383-7223
Vivace Networks/2730 Orchard Parkway/San Jose, CA 95134/fax:408-904-4748
http://www.vivacenetworks.com

---

From: "Motty Anavi" <[email-masked]>
Date: Wed, 7 Mar 2001 15:07:54 -0500

Andy,
    There are some differences that can be overcome by existing mechanisms.
We would add more on the technical steps and corrections that can be made to
make IP/UDP a suitable transport.

-- Cheers, Motty

> Sent: Tuesday, March 06, 2001 4:25 PM
> To: Motty Anavi
> Cc: Andrew G. Malis; [email-masked]; Yaakov Stein; Schwarzbauer Hanns
> Juergen
> Subject: RE: [PWOT] draft-anavi-tdmoip-01.txt
>
>
> Motty,
>
> > > draft-boyle-sts-ip-00.txt and
> draft-malis-sonet-ces-mpls-03.txt, such as