Subject: [PWE3] I-D Action:draft-ietf-pwe3-fc-encap-08.txt

From: [email-masked]
Date: Tue, 19 Aug 2008 12:45:01 -0700 (PDT)

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Pseudowire Emulation Edge to Edge Working Group of the IETF.

	Title           : Encapsulation Methods for Transport of Fibre Channel frames Over MPLS Networks
	Author(s)       : M. Roth, et al.
	Filename        : draft-ietf-pwe3-fc-encap-08.txt
	Pages           : 40
	Date            : 2008-08-19

A Fibre Channel pseudowire (PW) is used to carry Fibre Channel frames 
over an MPLS network. This enables service providers to offer 
"emulated" Fibre Channel services over existing MPLS networks. This 
document specifies the encapsulation of Fibre Channel PDUs within a 
pseudowire. It also specifies the procedures for using a PW to 
provide a Fibre Channel service.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-pwe3-fc-encap-08.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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From: [email-masked]
Date: Tue, 26 Aug 2008 18:35:14 -0400

The draft was posted this time.  I've diff'ed this draft against the
-07 version.  The results look good; I have a few minor edits to the
new timing material in Section 7:

OLD:
   while the device is unable to forward these Primitive Sequence due to

   backpressure indication, it shall flush its respective buffer (PSN-
   facing if the Primitive Sequences were received from the CE, CE-
   facing if they were received from the remote PE), and shall forward 
   the Primitive Sequences. 
    
NEW: (change "shall" to "MUST") 
   while the device is unable to forward these Primitive Sequence due to

   backpressure indication, it MUST flush its respective buffer (PSN-
   facing if the Primitive Sequences were received from the CE, CE-
   facing if they were received from the remote PE), and MUST forward 
   the Primitive Sequences. 

OLD:
   Another case is when there is no specific backpressure indication, 
   rather Primitive Sequences are being delayed due to retransmission of

   dropped frames. In this case also, the PE shall flush its PSN-facing 
   buffer and shall forward the Primitive Sequences.

NEW: (clarify paragraph, add retransmission sentence, add explanation
	of why R_T_TOV is important)
   Another case is when there is no specific backpressure indication, 
   but the Primitive Sequences cannot be immediately forwarded
   due to frames awaiting retransmission that must be sent first.
   In this case, the PE MUST flush its PSN-facing buffer and MUST
   forward the Primitive Sequences.  Long sequences of the same
   Primitive Sequence MUST be suppressed as described in [FC-BB].

   If the buffer clearing actions described in the previous paragraphs
   fail to ensure that the round trip latency for Primitive Sequences
   is less than R_T_TOV, the Fibre Channel link that is carried by the
   pseudowire may fail or may go offline and remain in that state
   because an R_T_TOV timeout in used in Fibre Channel's Link
   Initialization,  Link Failure and Link Reset protocols (see
   Section 7 of [FC-FS]).  Therefore, the FC PW SHOULD NOT be used
   when the latency across the FC PW may exceed 0.5 * R_T_TOV.

OLD:
   To guarantee correct operation of this mechanism FC PW SHOULD NOT be 
   used in environments where the RTT may have high variability, i.e., 
   environments where the estimated RTT may not be off by more than 5% 
   of MIN(E_D_TOV,R_A_TOV).
NEW:
   To guarantee correct operation of this mechanism FC PW SHOULD NOT be 
   used in environments where the RTT may have high variability, i.e., 
   environments where the estimated RTT may be off by more than 5% 
   of MIN(E_D_TOV,R_A_TOV).                ^   
                                           |
Remove "not" ------------------------------/

I think this is ready to go with these changes - if we treat the last
one as a thinko, they're all editorial and could be dealt with at IETF
Last Call.

Thanks,
--David

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Sent: Tuesday, August 19, 2008 3:45 PM
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Subject: [PWE3] I-D Action:draft-ietf-pwe3-fc-encap-08.txt

A New Internet-Draft is available from the on-line Internet-Drafts
directories.
This draft is a work item of the Pseudowire Emulation Edge to Edge
Working Group of the IETF.

	Title           : Encapsulation Methods for Transport of Fibre
Channel frames Over MPLS Networks
	Author(s)       : M. Roth, et al.
	Filename        : draft-ietf-pwe3-fc-encap-08.txt
	Pages           : 40
	Date            : 2008-08-19