Re: [TICTOC] Comments about draft-ietf-tictoc-shpiner-multi-path-synchronization-00
Doug Arnold <darnold@symmetricom.com> Fri, 21 December 2012 20:41 UTC
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From: Doug Arnold <darnold@symmetricom.com>
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Thread-Topic: [TICTOC] Comments about draft-ietf-tictoc-shpiner-multi-path-synchronization-00
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Date: Fri, 21 Dec 2012 20:41:45 +0000
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Subject: Re: [TICTOC] Comments about draft-ietf-tictoc-shpiner-multi-path-synchronization-00
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This is an interesting proposal. I believe that some kind of multi-path scheme for timing packets has value. In section 5.2.1 (Two-way MPPTP) it states: Every clock periodically sends a set of N Announce messages, using its N addresses as the source IP address. In 1588, however, only the best master sends multicast Announce messages. Slaves never send Announce messages, and non-best masters do only if they set the Alternate Master Flag (see IEEE-1588-2008, sec. 17.4). However, masters can obtain slave addresses from received Delay Requests. Also, if masters used the Alternate Master Flag, it would help prevent slaves which are not capable of mulit-path, from getting confused. Alternatively this could be done without Alternative Masters, using the Unicast Discovery mechanism (IEEE-1588-2008, sec. 17.5) In this mechanism slaves must start with a list of master addresses. The slaves then send unicast Announce message requests to the addresses, and subsequently receive unicast Announce messages. //Doug Arnold Symmetricom
- Re: [TICTOC] Comments about draft-ietf-tictoc-shp… Doug Arnold
- Re: [TICTOC] Comments about draft-ietf-tictoc-shp… Tal Mizrahi