Subject: Summary for draft-ietf-pwe3-sonet-vt-00.txt

From: "Prayson Pate" <[email-masked]>
Date: Mon, 2 Sep 2002 08:07:38 -0400

As requested by Danny, please find below the summary statement
for draft-ietf-pwe3-sonet-vt-00.txt.

NAME OF I-D:

http://www.ietf.org/internet-drafts/draft-ietf-pwe3-sonet-vt-00.txt
[SONET-VT]

SUMMARY:

This draft describes the service-specific implementation and
requirements for Pseudo-Wire Emulation Edge-to-Edge (PWE3) of
TDM circuits using SONET/SDH payload formats over packet
networks using IP or MPLS. This draft extends SONET/SDH SPE
emulation proposal draft-ietf-pwe3-sonet-00.txt , providing
SONET VT1.5/2/3/6 and SDH VC-11/12/2 circuit emulation. This
draft also provides bandwidth saving modes for SONET STS-1
and SDH VC-3/4 carrying tributaries or asynchronous T3/E3
streams.   It also enables virtual cross connect capability
between TDM ports and SONET/SDH ports in the PSN.

RELATED DOCUMENTS:

http://www.ietf.org/internet-drafts/draft-ietf-pwe3-sonet-00.txt [SONET]
http://www.ietf.org/internet-drafts/draft-cohen-pwe3-tdmsonetapp-00.txt
[APPST]
http://www.ietf.org/internet-drafts/draft-vainshtein-cesopsn-03.txt
[CESoPSN]
http://www.ietf.org/internet-drafts/draft-davari-pwe3-aal12-over-psn-00.txt
[AAL]
http://www.ietf.org/internet-drafts/draft-anavi-tdmoip-04.txt [TDMoIP]
http://www.ietf.org/internet-draftsdraft-ietf-pwe3-framework-01.txt [FW]

WHERE DOES IT FIT IN THE PICTURE OF THE PWE3 WORK:

The following set of drafts provides a complete solution for
the WG work item "TDM (e.g. DS1, DS3, SONET)":
- [SONET] describes how to carry STS-1 and STS-Nc SPEs over
  IP and MPLS PSNs.
- [SONET-VT] extends [SONET] to sub-SPE streams.  It is
  optimized for VT level cross connect applications, for PDH
  to SONET/SDH emulation and for carrying PDH circuits across
  a PSN.
- [CESoPSN] provides a simple and effective means for transport
  of native T1/E1 circuits over PSNs.
- [APPST] provides an applicability statement for the drafts
  listed above.

WHY IS IT TARGETED AT THIS WG:

The PWE charter calls for encapsulation and emulation/maintenance
document(s) for "TDM (e.g. DS1, DS3, SONET)".

This draft, together with [SONET], describes how to transport these
streams in a standard SONET/SDH format over IP and MPLS.

JUSTIFICATION:

Along with the previously mentioned drafts, this draft addresses
one of the work items in the WG charter, namely "TDM (e.g. DS1,
DS3, SONET)".  This is a very important work item for the PWE3 WG.

The following passage is from section 2.1.4 of the framework [FW]:

   As packet traffic takes up a larger and larger portion of the
   available network bandwidth, it becomes increasingly useful to
   optimize public networks for the Internet Protocol.  However, many
   service providers are confronting several obstacles in engineering
   packet-optimized networks.  Although Internet traffic is the fastest
   growing traffic segment, it does not generate the highest revenue per
   bit.  For example, Frame Relay traffic currently generates a higher
   revenue per bit than do native IP services.  Private line TDM
   services still generate even more revenue per bit than does Frame
   Relay.  In addition, there is a tremendous amount of legacy equipment
   deployed within public networks that does not communicate using the
   Internet Protocol.  Service providers continue to utilize non-IP
   equipment to deploy a variety of services, and see a need to
   interconnect this legacy equipment over their IP-optimized core
   networks.

This draft addresses the scenarios described above using existing
SONET/SDH technology as a base, providing these benefits:

1) SONET/SDH is a mature technology and popular technology.  It
   is well documented and is known to operate well in practice.
2) The vast majority of circuit services are provided today
   using existing SONET/SDH networks.  By using the approach
   described in this drat, service interworking between PWE3
   and SONET/SDH networks is simplified.
3) ASICs implementing SONET framers and mappers is commercially
   available, as is the software to control and support them.
   This draft allows implementers to leverage this existing base
   of hardware and software to facilitate development of equipment.
4) The fractional STS-1 mode allows for bandwidth conservation
   when not all timeslots are in use.
5) The timing mechanism of pointer justifications allows the
   simple conveyance of timing information, without the use of
   patented technology like SRTS.

The PWE3 WG should move this draft forward for the following reasons:

1) It is a part of a consistent set of drafts: [SONET], [SONET-VT],
   [CESoPSN] and [APPST].

2) As described above, this draft leverages existing and proven
   SONET/SDH technology.

3) The are a number of implementations, proving the practicality of
   this approach.

Prayson Pate - Overture Networks
Ron Cohen - Lycium Networks
David Zelig - Corrigent Systems

---

From: Shahram Davari <[email-masked]>
Date: Tue, 3 Sep 2002 10:51:42 -0700

Hi,

This summary mentions a couple of times that this draft is a 
part of a set of consistent drafts including the CESoPSN draft.

I wanted to know what is the consistency between CESoPSN draft and this draft.
If you mean that CESoPSN complements this draft, then so does the TDMoIP draft.

In my opinion your draft is completely independent of how native
T1/E1 is transported over a PSN.

Yours,
-Shahram

> -----Original Message-----
> From: Prayson Pate [mailto:[email-masked]]
> Sent: Monday, September 02, 2002 8:08 AM
> To: [email-masked]
> Cc: Danny McPherson
> Subject: [PWE3] Summary for draft-ietf-pwe3-sonet-vt-00.txt
> 
> 
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