Ordinary Clock Mode; Transparent Clock Mode - Lenovo RackSwitch G8264 Application Manual

Ordinary Clock Mode

Transparent Clock Mode

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When the RackSwitch G8264 is configured as an ordinary clock, it synchronizes its
clock with the master clock. If the G8264 does not detect a master clock, it will not
synchronize its clock with any other device. In this mode, the G8264's clock cannot
be modified manually or using another time protocol such as Network Time
Protocol (NTP).
As an ordinary clock, the G8264 synchronizes with a single PTP domain. The
switch uses a delay‐request mechanism to synchronize with the master clock. The
switch uses a source IP address for the packets it generates. You can create a
loopback interface for this purpose. By default, the switch uses the lowest interface
in the VLAN from which the sync messages are received. To assign a loopback
interface, use the following command:
RS G8264(config)# ip ptp source­interface loopback <interface number>
Note: If there are no interfaces on the switch that belong to the VLAN from which
the sync messages are received, then the ordinary clock will not function. An error
message will be generated. You can view this message using the
RS G8264# show ptp command.
When the G8264 is configured as a transparent clock, its time can be set manually
or using any time protocol. You must configure PTPv2 for the transparent clock to
function. The switch does not modify PTPv1 packets as they pass through the
switch.
As a transparent clock, the G8264 supports syntonization (synchronization of clock
frequency but not time) and synchronization with multiple domains.
Event packets received on all ports on the switch that have PTP enabled will be
adjusted with the residence time. The switch sends all PTP packets to the multicast
group address: 224.0.1.129. You can use Protocol Independent Multicast (PIM),
Internet Group Management Protocol (IGMP), or any other multicast protocol to
route the PTP packets.
Chapter 14: Precision Time Protocol
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