Ieee 1588V2 Ptp - Alcatel-Lucent 7450 Basic System Configuration Manual

IEEE 1588v2 PTP

Precision Time Protocol (PTP) is a timing-over-packet protocol defined in the IEEE 1588v2
standard 1588 PTP 2008. Support for PTP is dependent on both platform and software
release; check the release notes for applicability.
PTP may be deployed as an alternative timing-over-packet option to ACR. PTP provides the
capability to synchronize network elements to a Stratum-1 clock or primary reference clock
(PRC) traceable frequency source over a network that may or may not be PTP-aware. PTP
has several advantages over ACR. It is a standards-based protocol, has lower bandwidth
requirements, can transport both frequency and time, and can potentially provide better
performance.
The PTP functionality has dependencies on hardware components in the applicable platform.
Refer to the relevant release notes for details.
Support is provided for an ordinary clock in slave or master mode or a boundary clock. When
configured as an ordinary clock master, PTP can only be used for the distribution of a
frequency reference, not a time reference. The boundary clock and ordinary clock slave can
be used for both frequency and time distribution.
The ordinary clock master, ordinary clock slave, and boundary clock communicate with
neighboring IEEE 1588v2 clocks. These neighbor clocks can be ordinary clock masters,
ordinary clock slaves, or boundary clocks. The communication can be based on either unicast
IPv4 sessions transported through IP interfaces or multicast Ethernet transported through
Ethernet ports.
For the unicast IP sessions, the external clocks are labeled 'peers'. There there are two types
of peers: configured and discovered. An ordinary clock slave or a boundary clock should have
configured peers for each PTP neighbor clock from which it might accept synchronization
information. The router initiates unicast sessions with all configured peers. An ordinary clock
master or boundary clock will accept unicast session requests from external peers. If the peer
is not a configured peer, then it is considered a discovered peer. An ordinary clock master or
boundary clock can deliver synchronization information toward discovered peers.
shows the relationship of various neighbor clocks using unicast IP sessions to communicate
with a 7750 SR configured as a boundary clock with two configured peers.
Basic System Configuration Guide
System Management
Figure 15
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