DXD/PTP/GPS User Manual (rev 2.10)
Page 23
16.3 NETWORKING HARDWARE
•
PTP-aware
: PTP is implemented in some networking hardware often referred to as ‘PTP-aware’, meaning either as an
IEEE 1588 “Transparent Clock” or “Boundary Clock”. This includes switches and routers. Transparent Clocks and
Boundary Clocks are designed to improve accuracy particularly in large and busy environments.
•
Non-PTP-aware and
QoS
: The DXD-8 has been observed to perform very well with standard non-PTP switches. It
adheres to the IEEE 1588 2008 Annex D recommendation that, for PTP event messages, the value of the differentiated
service (DS) field in the Type of Service (ToS) field is set to the highest traffic class selector codepoint available, which in
this case is the DSCP value "High Priority / Expedited Forwarding (EF)”. This means that, with a switch properly
configured for Quality-of-Service (QoS), PTP traffic from the DXD-8 will be prioritized over other traffic.
•
Router/DHCP
: It is always required to have a router visible to the DXD on the network when using DHCP. Without the
router (and the DHCP server), fixed IP addresses must be used and set manually in menu 4.1.
•
IGMP - internet Group Management Protocol
: The DXD-8 supports IGMPv2. On larger networks, a router is
required to manage multicast group membership. Switches that support IGMP snooping are also recommended.
17. Troubleshooting - Error / Warning Messages
17.1 PTP ‘NO PORT’ WARNING
With PTP Mode selected as the reference a warning message will appear when the port has not been turned on.
This message indicates 3 possible causes:
•Port Mode not assigned
•Missing IP address
•Network disconnected.
If the port has been turned on but the warning message appears, it would indicate that the PTP
initialization request has not been granted. This could happen because the IP address hasn’t
been set properly, possibly due to a DHCP error.
-
Make sure the port has been turned on (menu 5.1)
-
Make sure the port has an IP address (menu 4.1)
17.2 PTP PORT IN PASSIVE STATE
Per IEEE 1588, a port in Passive state is not the master on the path nor does it synchronize to a master.
•Master Only: In a case where the DXD-8 is referenced to it’s internal crystal, to GPS or to a source connected via one of the 2
BNC inputs, the PTP port becomes master-only. In such a scenario, if another unit is selected by the BMCA as the master for
that domain, the port will switch to the Passive state.
-
If the port must be the Master on that domain, make sure Priority 1 is set low enough (menu 5.2)
PTP NO PORT
Possible causes include:
- PORT MODE not assigned
- Missing IP Address
- Network disconnected
Press Any Key to Exit
