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8 Embedded Web Server
Fig 8-8: Upper Section of PTP Profiles Web Page
Profile Select
– This dropdown list selects the profile to view and change
settings. All of the available profiles can be edited.
Reset to Defaults
– Selecting this checkbox and pressing the submit button
resets the selected profile to the default settings for that profile.
Delay Mechanism
– This selects the method for calculating and maintaining
the clock synchronisation communication delay between master and
slave devices. Both P2P (Peer to Peer) and E2E (End to End) methods are
supported. The best method for a particular installation will depend on the
type of network hardware used. If all the switches are known to be IEEE
1588 capable, P2P should be used. Otherwise it is best to use E2E.
Announce Interval
– This is the rate at which the announce message is sent,
one per the selected time. The announce message forms part of the Best
Master Clock Algorithm (BMCA) and contains the properties of the clock
which sends it. If a device receives an announce message from a better
clock, it will enter the slave state.
Announce Timeout
– This is the time the unit will wait for an announce
message and is a multiple of announce intervals. If no announce messages
are received within the timeout interval, the unit will assume the role of
grandmaster.
Sync Interval
– This is the rate at which the sync message is sent, one per
the selected time. The sync and follow up messages are sent from the
master to the slave to determine the difference in clock frequency. This
information is used in conjunction with the network delay to synchronise
the clocks.
Delay Request Interval
– This defines the rate at which a slave clock sends
delay request messages to the master. The delay request message allows
a slave device to calculate the network delay from the slave to the master.
This option is only valid when using the E2E delay mechanism.
Peer Delay Request Interval
– This is the rate at which a device exchanges
peer delay measurement messages. This allows each unit to track the
network delays between itself and its connected neighbours. This option is
only valid when using the P2P delay mechanism.
Priority 1 & Priority 2
– These values define a precedence setting used
by the best master clock algorithm when selecting a grandmaster clock.
Priority 2 defines a fine tune setting when multiple clock sources have
similar ordering criteria.
Domain
– This defines the group of PTP devices that the unit will
communicate with.
