RAD Data comm IPmux-1 - Manual (Page 29)

IPmux-1/1E Installation and Operation Manual Chapter 1 Introduction
Functional Description 1-21
integer between 1 and 8. Configuring TDM bytes/frame to a higher value reduces
the IP/Ethernet overhead segment of the total packet and thus can significantly
reduce the total Ethernet throughput.
On the other hand, packetization delay and intrinsic packet delay variation (PDVT)
are increased; this contributes to a higher end-to-end delay. This effect can be
small and negligible when a full E1 (or many timeslots) are transferred but can be
very significant when few timeslots are transferred. In this case, the packetization
delay and the intrinsic PDV when configuring a large value of
TDM bytes/frame can be very large and may exceed the maximum PDVT (jitter)
buffer on the receiving end. Table 1-4 and Table 1-5 show throughput as a
function of the TDM bytes/frame configuration for full E1 and full T1.
Table 1-4. Ethernet Throughput – Unframed E1
TDM
bytes/frame Frame
Length
(bytes)
Overhead
(bytes) Overhead
(%) Packets
per
Second Throughput
(Mbps)
48 94 46 96 5447 4.1
96 142 46 48 2724 3.1
144 190 46 32 1816 2.76
192 238 46 24 1362 2.6
240 286 46 19 1089 2.5
288 334 46 16 908 2.43
336 382 46 14 778 2.38
384 430 46 12 681 2.34
Table 1-5. Ethernet Throughput – Unframed T1
TDM
bytes/frame Frame
length
(bytes) Over head
(bytes)
Over head
(%)
Packets
per
Second Throughput
(Mbps)
48 94 46 96 4107 3.08
96 142 46 48 2054 2.32
144 190 46 32 1369 2.07
192 238 46 24 1027 1.95
240 286 46 19 821 1.87
288 334 46 16 685 1.82
336 382 46 14 587 1.78
384 430 46 12 513 1.76
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