Hi Antti,

Just to mention that I have a similar analysis as yours for the phase/time 
architecture.

And I also agree with Mike's comment: let's first discuss what the architecture 
will be, and it will automatically determine what to do with the protocols, as 
well as where there might be issues to be solved.

Thanks.

BR, 

Sébastien

-----Message d'origine-----
De : [email protected] [mailto:[email protected]] De la part de 
Pietilainen, Antti (NSN - FI/Espoo)
Envoyé : mercredi 4 août 2010 09:58
À : ext Shahram Davari; ext Mikael Abrahamsson
Cc : [email protected]
Objet : Re: [TICTOC] FW: 1588 over MPLS draft

Hi Shahram,

So let's clarify a little. Unlike in the case of frequency synchronization I 
don't expect multiple timing flows going across the network in the case of time 
synchronization. Instead, I expect that the network nodes create a 
synchronization hierarchy and synchronize the whole network. Probably BCs will 
be used. Synchronization service will be offered at the edges to customers. My 
view is based on analogy to Synchronous Ethernet. Note, however, that the 
architecture has not yet been discussed in depth in Q13 so other architectures 
are possible too.

If the architecture presented above is the way to go, the MPLS layer does not 
need to do any switching to the timing packets since they are terminated in 
every node. The timing protocol itself (not MPLS) decides what to do with the 
next hop. So the transporting problem is reduced to merely getting the packets 
across a single link. If one can accomplish that without bothering the MPLS 
layer, then we are all set just with OTN
- PTP interaction. 

There are several choices of physical layer media and L1 protocols. For each 
protocol and medium one needs to separately solve how the physical layer 
information is associated with the timing protocol.

Best regards, Antti  

-----Original Message-----
From: ext Shahram Davari [mailto:[email protected]]
Sent: Tuesday, August 03, 2010 8:29 PM
To: Pietilainen, Antti (NSN - FI/Espoo); ext Mikael Abrahamsson
Cc: [email protected]
Subject: RE: [TICTOC] FW: 1588 over MPLS draft

Hi Antti,

I don't understand how 1588 over OTN/SONET can solve the problem of 
transporting 1588 over an MPLS network. Are you saying all networks must use 
OTN or SONET? 

Thanks,
Shahram

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of 
Pietilainen, Antti (NSN - FI/Espoo)
Sent: Tuesday, August 03, 2010 4:54 AM
To: ext Mikael Abrahamsson
Cc: [email protected]
Subject: Re: [TICTOC] FW: 1588 over MPLS draft

Hi Mikael,

> More and more networks are built with DWDM optics being put directly 
> into routers/switches, ie no OTN at all.

By no OTN at all, do you mean, eg. 10GE interface? Ethernet interfaces should 
not require any changes to IETF protocols when Q13 is developing the time 
profile even though IP and UDP protocols might be utilized.

As said earlier, the major IP/MPLS vendors are very well presented in Q13, and 
therefore the IETF and IEEE802 standards have been respected very well there 
(which, unfortunately cannot be said about some other groups in ITU).

Best regards, Antti
 

-----Original Message-----
From: ext Mikael Abrahamsson [mailto:[email protected]]
Sent: Tuesday, August 03, 2010 1:38 PM
To: Pietilainen, Antti (NSN - FI/Espoo)
Cc: ext Yaakov Stein; [email protected]
Subject: Re: [TICTOC] FW: 1588 over MPLS draft

On Tue, 3 Aug 2010, Pietilainen, Antti (NSN - FI/Espoo) wrote:

> Tell me if Im wrong but I guess that the dominant client layer of, for

> example OTN, is MPLS. If one solves the MPLS case, then one solves the

> OTN case for a dominant proportion of OTN cases. On the other hand, if

> one solves timing over OTN without using the MPLS layer, then one does

> not need to solve how to carry time over MPLS whenever layer 1 is OTN.

More and more networks are built with DWDM optics being put directly into 
routers/switches, ie no OTN at all. Future framers might be switchable between 
G.709(with FEC), 10GE WAN/LAN phy, and other framing standards, but this is not 
the case today.

So any packet standard addressed by this WG should look at doing the standard 
over packet (and not just MPLS, it should be over IPv4/IPv6 which might be 
carried by MPLS, but this should not be a requirement).

-- 
Mikael Abrahamsson    email: [email protected]
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