MediaGateway
User Manual
83
5.3
Propagation delay measurement
For the correction adjust of the time reference transmitted by the Sync and Follow Up
Packets, the delay between the initiator of the protocol „Time-aware system i-1“ and
the first slave port of the MediaGateway „Time-aware system i“, should be measured.
𝐷𝐷
=
𝑡𝑡
𝑖𝑖𝑖𝑖
+
𝑡𝑡
𝑖𝑖𝑖𝑖
2
=
(
𝑡𝑡
4
− 𝑡𝑡
1
)
−
(
𝑡𝑡
3
− 𝑡𝑡
2
)
2
Figure 5-2: p_delay messages and formula
The measures of the propagation delay are performed by each attached link of an
802.1AS communication, which means that each side of the link will generate and
response to these packets, called
Pdelay_Request
Pdelay_Response
Pdelay_Response_Follow_Up.
