Nortel Remote Office 9150 Installation And Administration Manual page 435

March 2000
Propagation delay
Propagation delay is affected by the mileage and medium of links traversed.
Within an average size country, the one-way propagation delay over terrestrial
lines is under 18 ms. Within the United States, the propagation delay from coast-
to-coast is under 40 ms. To estimate the propagation delay of long-haul and
transoceanic circuits, use 1 ms per 100 terrestrial miles.
If a circuit goes through a satellite system, estimate each hop between earth
stations to contribute 260 ms to the propagation delay.
Serialization delay
This is the time it takes to transmit the voice packet one bit at a time over a WAN
link. The serialization delay depends on the voice packet size and the link
bandwidth, and is given by the following formula:
Serialization delay in ms = 8*(IP packet size in bytes)/(link bandwidth in Kbps)
The following table shows the serialization delay for voice packets on a 64 Kbps
and 128 Kbps link. The serialization delay on higher speed links is considered
negligible.
Codec
G.711A
G.711U
G.726
G.729A
G.729 Annex AB
Installation and Administration Guide
Serialization delay
Frame duration over 64 Kbps link (ms)
10 ms 14.00
20 ms 24.00
30 ms 34.00
30 ms 20
10 ms 5.25
20 ms 6.50
30 ms 7.75
Network engineering guidelines
Serialization delay over
128 Kbps link (ms)
0.88
1.50
2.13
12
0.33
0.41
0.48
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