Hi Manev, My comments are more or less the same as submitted for the -00 draft. The document does not differentiate well the topic of MPLS transport mapping with the individual clock types along the reference chain (specifically TC). It leads the reader to conclude that the transport of 1588 over MPLS requires TCs.
Perhaps a generic architecture diagram may be useful. 1) A few places in the text the phrase "proper handling of these packets" or "properly handle PTP messages" or "perform proper processing" is used to mean transparent clock. I would propose to remove such language as from the ITU-T studies of timing performances of PTP one could argue the "proper" way is to implement a boundary clock. Where the intention is to aid the designer of a TC that is fine to describe the implementation recommendation, but not to suggest this is the way to acheive the best performance or even the desired way to deploy PTP over MPLS. Refer to first paragraph of Abstract, and first paragraph of Problem Statement (section 3) 2) I would like to see a statement added in the document that the performance aspects (e.g. the phase or frequency alignment) are outside the scope of the document. Refer to fifth paragraph of Introduction(section 1) where performance of TC is mentioned and TCs are mentioned as the way ensure synchronization objectives are met. 3) The 1588 message transport section 6 it lists sync, delay_req, pdelay_req and pdelay_resp as requiring TC processing. I believe also Follow_Ups are handled for two-step or the conversion from one-step to two-step. I think also pdelay_resp_follow_ups aswell. In addition, syntonized TCs may handle the general messages aswell to figure out which flow to use as a syntonization source. 4) Section 6, 7, 8, 10 and 13 seems to focus only on the TC case between OC's and does not consider BC situation. 5) Section 12 text on checksums could be improved to indicate this only applies to TC and not to OC & BC. 6) Section 16 seems to address only TC clocks and not OC or BC clocks. 7) Section 16.3 implies that the only possible way to handle PTP is TC, excluding BC --- "don't have the capability to process 1588 packets (e.g. TC processing)" and " Non-1588-aware LSRs ignore the RSVP 1588_PTP_LSP object and just switch the MPLS packets carrying 1588 messages as data packets and don't perform any TC processing." ZARLINK Semiconductor Peter Meyer Timing & Synchronization Communication Products Group Office: +1-613-270-7203 | Fax: +1-613-592-1010 [email protected] | www.zarlink.com <[email protected]> Sent by: <[email protected]> 24/05/2011 06:41 PM To <[email protected]> cc <[email protected]> Subject [TICTOC] I-D Action: draft-ietf-tictoc-1588overmpls-01.txt A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Timing over IP Connection and Transfer of Clock Working Group of the IETF. Title : Transporting PTP messages (1588) over MPLS Networks Author(s) : Shahram Davari Amit Oren Manav Bhatia Peter Roberts Laurent Montini Filename : draft-ietf-tictoc-1588overmpls-01.txt Pages : 35 Date : 2011-05-24 This document defines the method for transporting PTP messages (PDUs) over an MPLS network to enable a proper handling of these packets (e.g. implementation of Transparent Clocks (TC)) in LSRs. The basic idea is to transport PTP messages inside dedicated MPLS LSPs. These LSPs only carry PTP messages and possibly Control and Management packets, but they do not carry customer traffic. Two methods for transporting 1588 over MPLS are defined. The first method is to transport PTP messages directly over the dedicated MPLS LSP via UDP/IP encapsulation, which is suitable for IP/MPLS networks. The second method is to transport PTP messages inside a PW via Ethernet encapsulation, which is more suitable for MPLS-TP networks. A URL for this Internet-Draft is: http://www.ietf.org/internet-drafts/draft-ietf-tictoc-1588overmpls-01.txt Internet-Drafts are also available by anonymous FTP at: ftp://ftp.ietf.org/internet-drafts/ This Internet-Draft can be retrieved at: ftp://ftp.ietf.org/internet-drafts/draft-ietf-tictoc-1588overmpls-01.txt _______________________________________________ TICTOC mailing list [email protected] https://www.ietf.org/mailman/listinfo/tictoc
_______________________________________________ TICTOC mailing list [email protected] https://www.ietf.org/mailman/listinfo/tictoc
