Subject: PWE3 IETF 55 Draft Minutes

From: Danny McPherson <[email-masked]>
Date: Sat, 23 Nov 2002 09:55:42 -0700

Please review minutes for accuracy & clarification and
send me comments ASAP.

Thanks!

-danny

============================================================
IETF 55 PWE3 WG Meeting
Atlanta, GA
November 21, 2002

Chair: Danny McPherson
Minutes Recorded by: [email-masked]

-----------------------
Meeting opens at 13:00

Administrivia - Danny McPherson
-------------------------------

Working Group Document Status: 

 o Requirements went through WG Last Call.  Several comments
   from WG, ADs and others added.  Redo of WG Last Call Dec '02.

 o Framework, Protocol Layering and Terms documents have been 
   folded into architecture.  Makes sense to be in one place. 
   WG Last Call Dec '02.  

 o Fragmentation document hasn't had much feedback. Chair
   doesn't think it is contentious.  WG Last Call Dec '02.

 o Ethernet: WG Last Call for March. A few editorial 
   and semantics changes.

 o Transport: Luca Martini will talk about this

 o SDH/SONET is on hold at the moment. Issues to be discussed
   with authors.

Miscellaneous Comments from Chair:

 o ADs are concerned that we must address congestion.  Must have way 
   to detect packet loss.  Sequencing and length semantics will be 
   put in architecture document and some generic text added to discuss
   congestion control with all service types will be added. 

 o Need Security considerations.

 o Terms must follow those defined in Architecture document and
   only introduce new service-specific terms.  

 o There MUST be a default mode for each service.

 o TDM requirements will be in a separate document.

 o Quote from Alison Mankin: "MSUT be a single default mode"

PWE3 Architecture Draft - Stewart Bryant
----------------------------------------

 o This is the 01 version of the doc. Includes framework and 
   Protocol Layering and terms document. 

 o All comments received are incorporated.

 o Changed diagram to remove RTP.

 o Structured bitstream: needs framing. Agreed with TDM groups.

 o RFC3378 text in security section: Need to be aware that security 
   risks may be higher than on a native network.

 o Operation of IPSec is already explicitly called up
 
 o Will add an extra short section on congestion.  This is not 
   payload congestion, but how you prevent PWs causing congestion 
   in the public Internet. Take packet loss, apply metric, or shut 
   down.

 o Control word: definition of common control word in architecture 
   document.

 o What is an Ethernet pseudo-wire?  PWE3 is consistent with 
   PPVPN, more complex models e.g. bridge, reside in PREP.

 o Terminology: At the last IETF we agreed a separate terminology 
   document.  There is now a consensus that we now delete the old 
   term draft. As a result of ITU-T work, need to tighten up on 
   terms.

 o Requests comments on the document before last call

Comments from floor:

Sasha Vainstein: Does Ethernet mean multiple pseudowires are out 
 of scope?
Stewart Bryant: No, CE->PE is a LAN segment.

Eric Rosen: If you want architecture document to have control word, 
  then it must be standards track
Comment: In other groups, it has been made Informational/BCP
Stewart Bryant: Will defer to Chair and ADs to decide on a status

PPVPN L2 Signalling --  Eric Rosen
----------------------------------

 o Presented in PPVPN yesterday

 o L2 VPN framework and PPVPN architecture aligned in terminology. 

 o Signalling connections 2 forwarders. Two forwarders are connected 
   by a PW using Martini signaling. Each forwarder independently 
   initiates LSP.  Problem: presupposes provisioning model. Each PW 
   individually provisioned.

 o No support for other PPVPN provisioning models. No integration 
   with L2VPN auto-discovery.

 o Solution: Generalise method of identifying remote forwarder. Allow 
   either forwarder to be the initiator, other to be the responder.

 o Martini signalling (PWE3 Transport/Control) currently doesn't have 
   provisions for this.

 o A number of examples and associated problems shown:

    Example 1: VPLS. Forwarders ID'd by VPN-ID. Current VPLS 
      proposals reuse martini VCid field as VPN ID.
    Example 2: Distributed VPLS.
    Example 3: VPWS full mesh model.
    Example 4: switched connections. E.g. ATM SVCs to PWs.

 o Going forward: ensure PWE3 signaling is general enough for PPVPN 
   to use (PWE3 draft?).  Specify use of PWE3 signaling for various 
   provisioning models (PPVPN draft?).

Mark Townsley: Current L2TPv3 spec includes identifier that is not 
  tied to 32 bit. This would match that well, so He supports it.
Habib Ould-Brahin: Good, but comment is not just VPNID, but a 
  general globally unique ID.
Ramula Eggarwal: good idea. Others propose to use BGP.

Eric Rosen: PPVPN is prohibiyed from defining protocols. This group 
  is defining protocols, and PPVPN model is based on PWs, so should 
  rely on the PWE3 sig mechanisms RE: sounds like PWE3 should set up 
  PWs.
Luce Martini: We are chartered to have maintenance protocol. Pt-pt,
  simple. Including some extensions for PPVPN isn't a problem, but I 
  don't think we should consider all of the PPVPN designs here. 
  Would like to receive comments from WG on including this. Not a bad 
  idea, but still it is pt-pt oriented.
Mohan: Some of these extensions fit very nicely.
Chair: In favour. Trivial to define semantics of extensible attributes
  to assist PPVPN in defining deployment scenarios, etc...
Marco Carugi: PPVPN wil clarify functional blocks for sig. DT will 
  work to clarify.  Which info we want to carry for different models. 
  For LDP, being done with same people in 2 groups.  Doesn't mean 
  this is the proposal.  Group doing protocol should define how. This 
  seems a clear way to proceed.  We want same sig for pt-pt and for 
  VPN models.

PW Management Discussion -- David Zelig
---------------------------------------

 o Provides a brief update. Shows general concept of the 
   generic MIB.

 o Connected to service layer MIB and PSN layer MIBs.

 o Very stable. No change from last IETF.  Waiting for control 
   plane last call.

 o PW MPLS MIB is very stable. 
 
 o Ethernet MIB is just a WG item. 

 o ATM MIB just expired. Needs to be respun. 

 o PW CEP MIB needs cleanup of unused objects.

 o Summary: Implementation experience exists but needs more 
   inputs.

 o Future additions: Notifications, use cases, and cleanup based 
   on implementation experience.

 o Frame relay coming soon. Good timing for MIB doctor review.

TDM Design Team Update -- Tom Johnson
-------------------------------------

 o Deadlock for about 2 years now. Design team was put together 
   to solve this.

 o Agreed: Max Riegel's requirements for going forward: services 
   going forward.  New revision by end of year.

 o Proposed compromise between 3 TDM drafts. Those 3 drafts split 
   into 2 camps.  Asking for 2 of the drafts as WG items.

 o All drafts will be aligned in terms of language, etc. Want to 
   put together a common framework.

Transport of ATM AAL1/2 frames over PSN -- Shahram Davari
---------------------------------------------------------

 o Described the compromise in TDM: have a structured draft,
   and an unstructured draft.

 o Proposes for PWE3 to adopt TDMoIP Anavi draft.

 o Applications: Leased line, private line, toll bypass.

 o Need to reuse as much as possible existing technology. AAL1 is 
   a proven technology, available in both hardware and software. 
   Has a number of desirable features, which are listed.

 o There is also a need to interwork with ATM. Carriers use ATM 
   CE in their network. Simple and inexpensive to use ATM SAR at 
   ATM and IP/MPLS boundary.

 o Slide showing how TDMoIP and ATM CES are converted.

 o Any Service and Port is an important architecture.

 o Current ASAPs support AAL1.

 o Easy to upgrade to IP/MPLS CES from current ASAP

 o TDMoIP is based on proven AAL1 technology. Off the shelf 
   hardware/SW.

 o Interwork seamlessly with ATM.

 o Asks WG to adopt TDMoIP.

Chair: Take proposal to mailing list.

Unstructured TDM (Sasha Vainshtein)
-----------------------------------

 o Presents motivation:

   - Many transport applications carry entire TDM stream 
     transparently.
   - An evolution of unstructured approaches presented 
     earlier in draft-vainstein-cesopen-03 and 
     draft-anavi-tdmoip-04.

   - Simple enough to overcome differences.
   - Supported by editors in separate drafts.

 o Scope: all unstructured services, except unstructured SONET/SDH.

 o Encap has been aligned with SONET/SDH.  RTP is part of the header. 
   Control word is mandatory.

 o Two modes of timestamp generation.

 o Procedures updated to handle local handling of lost packets.

 o Payload is carried as captured. Two payload sizes.

 o Issues: default payload size value is not yet specified. 
   DT is considering a compromise based on solutions for structured/
   unstructured.

Steve Casner: Is this consistent with AAL framing from previous talk?
Sasha V: this draft accommodates unstructured AAL1 attachment circuits.
Steve Casner: Does this proposal meet the agreement that previous talk said?
Sasha V: we are working on details of compromise. This proposal is part of the=20
  compromise.
Dave McDyson: Glad for compromise. I am unclear specifically what you are
  proposing.
Chair: Actual text of compromise is not in these drafts.

Explanation of TDM compromise -- Yakov Stein
--------------------------------------------

 o Previous draft is an unstructured draft only. This might be 
   progressed more easily. Problem is that we had no mandatory mode 
   and we must have this.  

 o There will be 2 TDM drafts: 

   Unstructured: 
   - raw bitstream at TDM rates
   - structured that has no impact on transport mechanisms

   Structured TDM: a single MUST mode and 2 optional main 
     modes. 

 o AAL1 and one AAL2 or dynamic bandwidth and ??

Sasha V: correction. There are 2 not 3 main modes in structured 
  TDM.  Yakov has correctly relayed compromise.

Issues with Control Word & Packet Loss -- Yaakov Stein
------------------------------------------------------

 o Presenter claims the intention matches well with the ADs

   Control word has:
    - Sequence number
    - Payload dependent flags
    - Packet length
    - Fragmentation
    - Payload type

 o We actual have 3 types of control word:
    - Martini CW
    - CEP Header
    - Fischer CW

 o Why 3 formats: Different services have different requirements, 
   but primarily different groups wrote different drafts and different 
   existing implementations.

 o Proposal: CW should be based on Martini draft.

Ron Cohen: don't understand motivation.  Really disagrees.
Mark Townsley: When running over PSN, there should be one control word.
  There is point of first nibble. The martini definition is very 
  friendly to existing P routers.=
Yakov Stein: Agrees and should deal with this
Ghassem Koleyni: Martini is compatible with ITU-T
Sasha Vainstein: Not sure we can force one control word structure.
Chair: ATM mode is the only one that employ "fischer" CW format and it's
  optional there.

Comment: Are you proposing that we have 2 types of sequence number: 
  one that wraps to 0 and one that doesn't?
Chair: Indeed Martini wraps to 1 and RTP wraps to 0.  Martini reasoning 
  for this is so tha 0 represents "no sequencing enabled" but field is 
  always present in CW.  We'll try to make this less confusing in the 
  architecture document.

Effects of Congestion -- Yakov Stein
------------------------------------

 o PWE3 needs to take congestion into account. Presenter Shows 
   effects of packet loss on voice quality.  Packets contain info 
   from lots of different voice channels.  
 
 o Graph comparing different techniques.  Packet loss concealment 
   can be built into VoIP.

 o Proposal: structured TDM transported. Encapsulation must be able 
   to easily support replay. Implementations should provide 
   interpolation.

Chair: Perhaps this needs to be in the requirements for TDM.
Sasha Vainstein: Unstructured TDM transport can do better than other
  methods.
Steve Cassner: In the structured case you always know if it is voice?
Yakov Stein: Yes
Steve Cassner: Do you pass an error?
Yakov Stein: As long as loss is good enough for toll voice, its OK
Stewart Bryant: If this is deemed of value after peer review, why not 
  progress as informational or best practice?
Chair: Take proposal to mailing list please.

Bi-directional LSPs for classical MPLS -- Rohit Dube
----------------------------------------------------

 o Previously presented at MEF and MPLS WG.

 o Presents definition for Bi-directional and symmetric LSP.

 o Benefits: Good fit for both PWE3 and MEF EVPL.

 o Better manageability.

 o Shows RSVP-TE extension required.
 
 o CSPF extension shown.

 o Proposal extends LSP setup mechanism.  Fits in MPLS WG and 
   presented to PWE3 for information.

Chair: Thanks for sharing...

Header Compression Drafts -- Jerry Ash
--------------------------------------

 o Motivation: carriers evolving to converged MPLS backbone 
   with VoIP services.  Enterprise VPN services with VoIP. 
   Legacy voice migration to VoIP.

 o Requirements are presented: needs efficient voice transport.
   
 o Support voice encoding. 
  
 o Compress/decompress header using cRTP or simple algorithm, operate 
   in 2547 VPN context, and be scalable.
 
 o Proposals: steps: 
    - use RSVP to establish LSPs between CE1-CE2. 
    - Use cRTP ?

 o Claimed Advantages: Minimises PE requirements

 o Claimed disadvantages: Ces need to run RSVP

 o Why PWE3: seems best fit, but not within current charter.

 o Review of Implementation issues, and changes to protocols.

Stewart Bryant: this does not fit here as it is radically different.
Steve Cassner: isn't an extension to cRTP, but an extension to 2509.
Chair:  Still need to discuss if/where this fits with ADs.

Any-MPLS Interworking in ITU-T -- Ghassem Koleyni
- -------------------------------------------------

 o Report on what happened in ITU-T in last 2 weeks. 

 o Agreed last time to incorporate Martini modes into ITU-T
   2 cell modes: 1-1 and N-1.=20

 o On cell modes, document sent for approval.

 o Reference diagrams shown for 1:1 and N:1 shown along with 
   encapsulation formats.

 o Voice over MPLS is also being discussed.

 o All referenced documents can be found online (IETF participants 
   have to register)

 o A liaison statement was sent to IETF explaining this.

Progress Update for ATM, Ethernet, Control Draft -- Luca Martini
----------------------------------------------------------------

 o ATM Draft is a merging of the ATM drafts (draft-martini, 
   draft-koleyni, draft-bocci) for cell modes and AAL5 modes.

 o We met in this IETF and agreed to some changes to the first 
   encapsulation document. 

 o We want to make one applicability section. Lots of editorial 
   work.

 o Remove MTU, sequencing, introduction terms/diagram, leave to 
   architecture document.

 o Agreement to make N-to-one cell the only mandatory mode.

 o Ethernet draft: Single mode for Ethernet encapsulation. 
    Todo: - remove control word sequencing, length. 
          - Remove appendix. 
          - WG last call.

 o Control Document: Since 00, refs updated, VLAN Request 
   interface parameter.  TODOs:
    - Considering protocol extensions draft-rosen-l2-signaling-02. 
    - New TLV for PW status
    - New TLV for IP address will be in separate document in 
      PPVPN
    - congestion control, seq, length will be put in arch draft 

Ramula Eggarwal: Ethernet: you mean encap, not PW type? 
Luca: Yes only one encap. 2 PW types but one encap.
Mark Townsley: Ethernet and control draft, a good amount of improvement.
  ATM document still has a lot to do.
Chair: applicability statements will determine the modes.
Ramula Eggarwal: There should be no such thing as mandatory and not
  mandatory.
Chair, agree: but unfortunately, this is the real world and we've made 
  lots of progress.  It's far better than where we were.
Craig White: should remove non-implemented modes from the drafts.

Meeting Adjourned.

---

From: Sasha Vainshtein <[email-masked]>
Date: Sun, 24 Nov 2002 07:35:30 +0200

Danny and all,
Please see a brief comment inline.

----------------------------------------------------------------------------
--------
With best regards,
                          Sasha Vainshtein
email:   [email-masked] <mailto:[email-masked]> 
phone:  +972-3-7659993 (office)
            +972-8-9254948 (home)
            +972-58-674833 (cellular)

> -----Original Message-----
> From: Danny McPherson [mailto:[email-masked]]
> Sent: Saturday, November 23, 2002 6:56 PM
> To: [email-masked]
> Subject: [PWE3] PWE3 IETF 55 Draft Minutes
> 
> 
> 
... snipped ...
> Effects of Congestion -- Yakov Stein
Actually I have only said that unstructured TDM can safely reply previous
packets provided that the packet payload size is a suitable multiple of 
the frame size of the original circuit. This corresponds to one of
the methods described in the draft. Other methods (linear interpolation,
statistical) really require structured TDM.
> _______________________________________________
> pwe3 mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/pwe3
>

---

From: Danny McPherson <[email-masked]>
Date: Sun, 24 Nov 2002 10:09:19 -0700

The minutes have been updated to reflect this.

-danny

---

From: Stewart Bryant <[email-masked]>
Date: Mon, 25 Nov 2002 11:53:35 +0000

>  o Quote from Alison Mankin: "MSUT be a single default mode"

Repetition and spelling

>  o Changed diagram to remove RTP.

Changed to include RTP for MPLS

> Stewart Bryant: this does not fit here as it is radically different.

Close: What I actually said was "Whilst I am sympathetic of the need
for a home for this work, it does not fit here, because it is radically 
different from any pseudo-wire type we are defining"

---

From: David Zelig <[email-masked]>
Date: Mon, 25 Nov 2002 14:09:02 +0200

Danny,
Few corrections and additions to the MIB presentation minutes.

> PW Management Discussion -- David Zelig
Should be : o PW-MIB is Very stable. No change from last IETF.  Waiting for
control plane last call.

>  o PW CEP MIB needs cleanup of unused objects.
Should be: o PW CEP MIB : did cleanup of unused objects.

>  o Frame relay coming soon. Good timing for MIB doctor review.
Separate to read:

 o Frame relay coming soon. 

 o Good timing for MIB doctor review.

Thanks
David