RE: [PWE3] question on draft-mohan-pwe3-vccv-eth-01.txt

["Dinesh Mohan" <[e-mail]>]

Folks,
 
As Dave, Peter, Himanshu and others have noted, we can keep discussing
the nuances of charter statements and whether this work item is in scope
or not etc. however, we cannot dictate whether or not a technology can
support multi-protocol encapsulations. IETF has done a decent job of
defining PW encapsulations and there is no point in restricting it to
only MPLS/IP. Ethernet is designed to carry Ethernet payloads and is
also designed to carry other payloads types e.g. ATM, FR, IP, MPLS etc.
Carrying of MPLS payload is called out in draft-allan-pwopbt, dry
martini etc activities, and is evidently already used in PHP across
Ethernet link or network between two adjacent LSRs.
 
Therefore PWs can be used across Ethernet networks. Even though Ethernet
OAM can be applied as is for managing PWs and Ethernet OAM does not rely
upon VCCV for providing management capabilities, the proposed extensions
are more guided by existing operational expectations in managing PWs
i.e. via VCCV. This is particularly true when MS-PW comes into play and
a uniform end-to-end PW management capability is desirable across
disparate network types.
 
Hopefully, we can get to more meaningful discussion of how we can
address this work either by expanding the charter or other means, rather
than discounting it simply based on procedural subtleties.
 
---
Dinesh

________________________________

From: Busschbach, Peter B (Peter) [mailto:[e-mail]]

Sent: Monday, March 05, 2007 7:00 PM
To: Andrew G. Malis
Cc: Mark Townsley; pwe3; Shah, Himanshu; Stewart Bryant
Subject: RE: [PWE3] question on draft-mohan-pwe3-vccv-eth-01.txt


Andy,
 
The charter language does not apply in the case of adjacent PEs. You
can't mandate that there be an MPLS network between adjacent PEs,
because then they would not be adjacent.
 
That said, I agree that the text in RFC4447 was not meant to sanction
PWs over Ethernet. We should update the charter and allow PWs over any
packet switched network.
 
Peter


________________________________

	From: Andrew G. Malis [mailto:[e-mail]] 
	Sent: Monday, March 05, 2007 6:50 PM
	To: Busschbach, Peter B (Peter)
	Cc: Mark Townsley; pwe3; Shah,Himanshu; Stewart Bryant
	Subject: RE: [PWE3] question on draft-mohan-pwe3-vccv-eth-01.txt
	
	
	Peter,
	
	Thanks for pointing that out. However, that doesn't change the
existing charter language.
	
	Cheers,
	Andy
	
	-------
	
	At 3/5/2007 05:43 PM -0600, Busschbach, Peter B \(Peter\) wrote:
	

		Andy,
		 
		I respectfully disagree. The text that I quoted says
"... if the pseudowire endpoints are immediately adjacent ...". Note the
"s" at the end of "endpoints". Therefore, the text is about adjacent PEs
and it says that in that case there is no need for an MPLS tunnel to
carry the PW. In other words, the PW can be carried directly over the
link layer between the adjacent PEs.
		 
		Peter
		
		

________________________________

			From: Andrew G. Malis [ mailto:[e-mail]
<mailto:[e-mail]> ] 
			
			Sent: Monday, March 05, 2007 6:33 PM
			
			To: Shah, Himanshu
			
			Cc: Busschbach, Peter B (Peter); Stewart Bryant;
Mark Townsley; pwe3
			
			Subject: RE: [PWE3] question on
draft-mohan-pwe3-vccv-eth-01.txt
			
			
			I would like to point out that the intent of the
RFC 4447 text quoted by Peter was to ONLY allow PHP to be used on the
physical link between the penultimate P router and the PE router where
the PW terminates and connects with the attachment circuit.  In this one
case only, the MPLS tunnel used to carry the PW terminates at the
penultimate P router rather than at the PE router. It was not meant to
be a general escape mechanism to allow the general use of PWs over
tunneling mechanisms other than MPLS or L2TPv3. 
			
			
			Further, to quote the WG charter,
			
			
			"Pseudowire Emulation Edge to Edge (PWE3) will
specify the
			
			encapsulation, transport, control, management,
interworking and
			
			security of services emulated over IETF
specified PSNs."
			
			
			Ethernet and SONET are not IETF specified PSNs.
			
			
			So, while there may be value in supporting PWs
over non-IETF-specified PSNs, I do agree with Stewart and Mark that a
charter change will be necessary to pursue this work.
			
			
			Cheers,
			
			Andy
			
			
			--------
			
			
			
			At 3/5/2007 05:51 PM -0500, Shah, Himanshu
wrote:
			

				Content-class:
urn:content-classes:message
				
				Content-Type: multipart/alternative;
				
	
boundary="----_=_NextPart_001_01C75F78.CAA52CEF"
				
				
				I believe this is a key point.
				
				In my view, discussions on in/out scope
				
				really does not apply (for the reasons
				
				described below). Also, note that as L2
				
				technology becomes more intelligent (eg.
PBT),
				
				keeping it out-of-scope (artificially)
would be
				
				a mistake.
				
				
				There are other docs (past/present),
that already
				
				use this concept, such as dry martini,
				
				MEF3/8 (TDM-PWoETH, except ethType is
different),
				
				pw-over-pbt, etc.
				
				
				IMO,
				
				himanshu
				
				
				
				-----Original Message-----
				
				From: Busschbach, Peter B (Peter) [
mailto:[e-mail]]
				
				Sent: Mon 3/5/2007 5:24 PM
				
				To: Stewart Bryant; Mark Townsley
				
				Cc: pwe3
				
				Subject: RE: [PWE3] question on
draft-mohan-pwe3-vccv-eth-01.txt
				
				
				Dave Allan made a point that I believe
is valid and makes this whole
				
				discussion irrelevant. To rephrase what
he said:
				
				
				Page 4 of RFC 4447 says:
				
				
				   In the protocol specified herein, the
pseudowire demultiplexor field
				
				   is an MPLS label.  Thus, the packets
that are transmitted from one
				
				   end of the pseudowire to the other
are MPLS packets, which must be
				
				   transmitted through an MPLS tunnel.
However, if the pseudowire
				
				   endpoints are immediately adjacent
and penultimate hop popping
				
				   behavior is in use, the MPLS tunnel
may not be necessary. 
				
				
				Based on this logic, PWs can be carried
over SDH, Ethernet or any other
				
				protocol that can carry MPLS packets
without violating the PWE3 charter.
				
				
				Peter
				
				
				
				> -----Original Message-----
				
				> From: Stewart Bryant
[mailto:[e-mail]]
				
				> Sent: Monday, March 05, 2007 1:35 PM
				
				> To: Mark Townsley
				
				> Cc: pwe3
				
				> Subject: Re: [PWE3] question on
draft-mohan-pwe3-vccv-eth-01.txt
				
				>
				
				>
				
				> So the proposal seems to be that PWE3
extends VCCV for use
				
				> with a PWE3 PW over a non IP/MPLS PSN.
				
				>
				
				> We should put this on the agenda for
Prague.
				
				>
				
				> - Stewart
				
				>
				
				>
				
				>
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