Subject: [TICTOC] on-path support type - clock on network element

From: Yaakov Stein <[email-masked]>
Date: Tue, 28 Jul 2009 18:03:06 +0300

The question was asked yesterday why it is useful to have a use case of on-path support
as a network element (switch or router) with a clock input.

Of course, if this clock is used to make the links SyncE, this is not a separate case.

I claimed that the clock could be used in other ways,
and it was asked why not, in that case, simply distribute it.

There are several reasons :

1)      the network element may be a network element that does not generate traffic towards users

2)      the clock may not be the clock that the user wants, but may improve the distribution of the clock that the user wants

 (think about common clock <differential> methods, or a transit domain with a ToD clock not locked to the user's national one)

3)      the clock may be used purely for network maintenance functions (as in Stewart's slides on use of accurate time in routers)

I am sure there are more cases as well.

Y(J)S