IEEE 1588 Analysis
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9.3.The Pseudo-slave Emulation Mode
The pseudo-slave emulation is similar to the slave emulation mode but the test unit now
keeps an independent synchronization source. Typically, a GNSS reference is used
but the test equipment could use any other reference such as ToD, 1 PPS, frequency
inputs or even the internal oscillator in holdover / free running states. From the outside,
the pseudo-slave and slave emulation modes are indistinguishable but internally they
are different. Now, the reference and test signals can be compared and the
measurement bandwidth could be extended to very low frequencies involving phase
variations of hours or days typical of wander tests. If a time reference such as GNSS
is used the Time Error (TE) could be computed as well. Finally, the pseudo-slave
operation mode is also compatible with background traffic generation. This feature
could be used to check any change in the TE, MTIE and TDEV depending on the traffic
load. Additionally, some special test metrics such as the Floor delay population test
require previous configuration of this PTP operation mode.
The pseudo-slave test mode is compatible both with the IP endpoint and the Ethernet
endpoint operation modes. If the test is to be run in IP endpoint mode, the user is
required to configure a valid IP profile (See section 9.2.1). Once the local profile has
been configured the steps to follow to enable the pseudo-slave mode are described
below:
1. Configure the clock reference input (See section 2.6).
2. From the Home panel, go to TEST,
The test configuration panel is displayed.
3. Go to PTP (IEEE 1588).
4. Configure the equipment to become a PTP pseudo-slave entity by configuring
PTP test to Tes t.
A label with the text PTP is displayed in the top notification area.
5. Set the transport protocol to either Ethernet or UDP.
Note: If you are operating in Ethernet endpoint mode, the UDP transport protocol
is not allowed.
6. Configure the Addressing mode to Unicast, Multicast or Hybrid depending on the
system where the test unit is to be connected.
7. Depending on the PTP profile implemented in your system, configure Path delay
mechanism to either End-to-end or Peer-to-peer.
8. Configure the Domain to the right value for your network.
9. If you have configured Addressing mode to Unicast, then you can configure one or
more PTP entities to communicate with from the Unicast master table menu
Note: Remote PTP entities are configured through their IP or MAC address,
depending on the Transport protocol.
10. Configure the timing of the different messages associated to PTP from the
Mes-
sage timing menu.
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