Subject: Re: [Detnet-dp-dt] [EXT] Re: Data Plane Approach - Synchronization Traffic

From: Jiangyuanlong <[email-masked]>
Date: Mon, 6 Feb 2017 12:22:31 +0000

Synchronization traffic can be categorized into two cases:
1. Synchronization as a service, high availability can be an advantage for this kind of service 
Synchronization service is transported from an ingress PE to an egress PE, replication/elimination can optionally be applied between two PEs (i.e., on S-PEs), while all network nodes including PEs and S-PEs are not aware of the sync message themselves (that is, they don't need to process the PTP messages in the service). And the egress PE will terminate and provide a single copy of each sync packet to a destination CE.

2. Synchronization as an infrastructure 
Since existing technology including SyncE and IEEE 1588 rely heavily on a tree topology to work properly, replication/elimination must not be used in this case.

My 2 cents,
Yuanlong

> -----Original Message-----
> From: Detnet-dp-dt [mailto:[email-masked]] On Behalf Of
> Jouni Korhonen
> Sent: Wednesday, February 01, 2017 4:25 AM
> To: Balázs Varga A
> Cc: Loa Andersson; Tal Mizrahi; [email-masked]
> Subject: Re: [Detnet-dp-dt] [EXT] Re: Data Plane Approach - Synchronization
> Traffic
> 
> Indeed. Not all traffic will receive the replication/elimination service. That is
> based on the configuration.
> 
> - Jouni
> 
> 
> --
> Jouni Korhonen, Broadcom Ltd.
> M: +1-408-391-7160
> 
> > On Jan 31, 2017, at 12:13 PM, Balázs Varga A
> <[email-masked]> wrote:
> >
> > Hi,
> > For sync usually we need hop-by-hop forwarding.
> > So it is not clear why to consider replication (and elimination) at all?
> > Cheers
> > Bala'zs
> >
> > -----Original Message-----
> > From: Detnet-dp-dt [mailto:[email-masked]] On Behalf Of
> > Tal Mizrahi
> > Sent: Friday, January 27, 2017 8:37 AM
> > To: Jouni Korhonen <[email-masked]>
> > Cc: [email-masked]; Loa Andersson <[email-masked]>
> > Subject: Re: [Detnet-dp-dt] [EXT] Re: Data Plane Approach -
> > Synchronization Traffic
> >
> >> In a path redundancy case would the PTP messages on multiple paths be
> >> exact copies a single origin PTP message or different PTP messages?
> >
> > They would be two different PTP messages.
> > This implies that we would not like PTP packets to be subject to replication
> and elimination.
> >
> > Tal.
> >
> >
> >> -----Original Message-----
> >> From: Jouni Korhonen [mailto:[email-masked]]
> >> Sent: Thursday, January 26, 2017 8:40 PM
> >> To: Tal Mizrahi
> >> Cc: Loa Andersson; [email-masked]
> >> Subject: Re: [Detnet-dp-dt] [EXT] Re: Data Plane Approach -
> >> Synchronization Traffic
> >>
> >>
> >>
> >>> On Jan 25, 2017, at 11:10 PM, Tal Mizrahi <[email-masked]> wrote:
> >>>
> >>> Hi Loa,
> >>>
> >>>
> >>>>> - If the answer is yes: not sure replication and elimination makes
> >>>>> sense for
> >> PTP.
> >>>>
> >>>> Why is that?
> >>>
> >>> In order for PTP to work well, PTP packets have to be consistently
> >>> sent over the
> >> same path. If packets are intermittently sent through two different
> >> paths (with two different delays) the PTP slave will not be able to
> synchronize in a stable way.
> >>> However, it *does* make sense for PTP to be sent through two
> >>> different paths
> >> *without* elimination at the end. Such path redundancy allows the
> >> slave to always receive the sync information through both paths,
> >> which actually allows more robust synchronization than over a single
> path.
> >>>
> >>> So path redundancy is good for PTP, but elimination - not so good.
> >>
> >> In a path redundancy case would the PTP messages on multiple paths be
> >> exact copies a single origin PTP message or different PTP messages?
> >>
> >> - JOuni
> >>
> >>
> >>>
> >>> Cheers,
> >>> Tal.
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Loa Andersson [mailto:[email-masked]]
> >>>> Sent: Thursday, January 26, 2017 9:01 AM
> >>>> To: Tal Mizrahi; [email-masked]
> >>>> Subject: [EXT] Re: [Detnet-dp-dt] Data Plane Approach -
> >>>> Synchronization Traffic
> >>>>
> >>>> External Email
> >>>>
> >>>> -------------------------------------------------------------------
> >>>> -
> >>>> -
> >>>> -
> >>>> Tal,
> >>>>
> >>>> On 2017-01-26 14:44, Tal Mizrahi wrote:
> >>>>> Hi,
> >>>>>
> >>>>> I realize this is a bit off-topic, but one of the things I am
> >>>>> wondering about is how
> >>>> synchronization traffic (PTP) is forwarded in the context of the
> >>>> data plane approaches we have been considering.
> >>>>> Is PTP transported as a DETNET flow?
> >>>>> - If the answer is no: does that mean we are assuming that
> >>>>> synchronization is
> >>>> achieved at a different layer, possibly requiring dedicated
> >>>> communication between the customer and provider?
> >>>>> - If the answer is yes: not sure replication and elimination makes
> >>>>> sense for
> >> PTP.
> >>>>
> >>>> Why is that?
> >>>>
> >>>> /Loa
> >>>>>
> >>>>> Will be happy to hear your thoughts, and apologies if this has
> >>>>> already been
> >>>> discussed elsewhere and I am not aware.
> >>>>>
> >>>>> Cheers,
> >>>>> Tal.
> >>>>> _______________________________________________
> >>>>> Detnet-dp-dt mailing list
> >>>>> [email-masked]
> >>>>> https://www.ietf.org/mailman/listinfo/detnet-dp-dt
> >>>>>
> >>>>
> >>>> --
> >>>>
> >>>>
> >>>> Loa Andersson                        email:
> [email-masked]
> >>>> Senior MPLS Expert                          [email-masked]
> >>>> Huawei Technologies (consultant)     phone: +46 739 81 21 64
> >>>
> >>> _______________________________________________
> >>> Detnet-dp-dt mailing list
> >>> [email-masked]
> >>> https://www.ietf.org/mailman/listinfo/detnet-dp-dt
> >
> > _______________________________________________
> > Detnet-dp-dt mailing list
> > [email-masked]
> > https://www.ietf.org/mailman/listinfo/detnet-dp-dt
> 
> _______________________________________________
> Detnet-dp-dt mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/detnet-dp-dt