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Using Master-Slave Protocol to Join a Peer Clock Synchronization Protocol

IP.com Disclosure Number: IPCOM000106167D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Azagury, A: AUTHOR [+6]

Abstract

In a typical peer clock synchronization protocol like [1,2] the prescribed protocol for joining is much more complex than the ongoing resynchronization protocol. The complexity results from a requirement that full members of the protocol share certain agreed on parameters (e.g., the next time to synchronize) and that they be sufficiently synchronized when they participate so as not to throw the resynchronization off. The problem is that to achieve this level of shared knowledge and synchronization, the joiner must either wait for the next scheduled synchronization or cause a special synchronization to occur for its benefit.

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Using Master-Slave Protocol to Join a Peer Clock Synchronization Protocol

      In a typical peer clock synchronization protocol like [1,2] the
prescribed protocol for joining is much more complex than the ongoing
resynchronization protocol.  The complexity results from a
requirement that full members of the protocol share certain agreed on
parameters (e.g., the next time to synchronize) and that they be
sufficiently synchronized when they participate so as not to throw
the resynchronization off.  The problem is that to achieve this level
of shared knowledge and synchronization, the joiner must either wait
for the next scheduled synchronization or cause a special
synchronization to occur for its benefit.

      The method is practiced as follows.  The joiner locates a
neighbor who is already a participant and then uses to use a
Master-Slave protocol such as Probabilistic Clock Synchronization
[3,4] to synchronize with the neighbor.

      Inspection of the timeliness tests used by the peer protocol
will show how tightly the joiner must synchronize in order to be
believed by the others.  Master-slave protocols typically allow the
participants to determine how closely they have synchronized so the
joiner can stop trying when it knows it has attained the required
degree of synchronization.  Since protocols like PCS usually allow
much tighter synchronization than peer protocols like Halpern, et.
al.  1, this method should usually allow the joiner to join with...