Chapter 7 Signal Delay and WAN Bandwidth Requirement IP6704A TDMoEthernet
Loop Telecommunication International, Inc.
164
7.
SIGNAL DELAY AND WAN
BANDWIDTH REQUIREMENT
This chapter provides formulas on how to calculate the delay time of delivering TDM data
and the bandwidth that is required for TDM data transmission. The results present in this
chapter are empirical and are derived from testing.
7.1.
Signal Delay from TDM Port to
Ethernet (WAN) Port
The TDMoIP frame format requires Ethernet, IP/UDP, control word, and payload header
for a total overhead of 48 bytes. The payload size (portion of E1 signal) carried by the
TDMoIP frame varies according to the format used, its associated parameters, and the
jitter buffer threshold (jitter delay in ms).
TDMoEthernet Payload has the following three payload types:
SAToP
CESoPSN
MEF8
Each payload format has its unique formula on calculating the delay time, all of which are
introduced in paragraphs below.
SAToP
When using the SAToP format, the following parameters are included:
the size of bytes in the payload: 24 to 1500 bytes
The delay time of SAToP format can be computed by the following formula, and a few
examples are shown in the tables below.
T
T
o
o
t
t
a
a
l
l
D
D
e
e
l
l
a
a
y
y
T
T
i
i
m
m
e
e
(
(
m
m
s
s
)
)
f
f
o
o
r
r
E
E
1
1
=
=
0
0
.
.
0
0
0
0
3
3
9
9
0
0
6
6
2
2
5
5
x
x
M
M
+
+
0
0
.
.
2
2
7
7
7
7
5
5
+
+
J
J
i
i
t
t
t
t
e
e
r
r
B
B
u
u
f
f
f
f
e
e
r
r
T
T
h
h
r
r
e
e
s
s
h
h
o
o
l
l
d
d
Table 7-1 Total Delay Time of SAToP (E1)
# of bytes in the payload (M)
1500
100
24
Jitter Delay (buffer threshold in ms)
20
3
1
Total Delay Time (ms)
26.14
3.67
1.37