Specifications

3000sb4.fm
P31003-H3560-X100-1-7618, 09/05
HiPath 3000/5000 V6.0, System Description
4-3
For internal use only
HiPath 3000/5000 in the LAN Network
Network Analysis
Payload connections with RTP (Real-Time Transport Protocol) in a LAN environment
The bandwidth required for voice transmission in an IP network can be calculated using the fol-
lowing table:
The LAN load is calculated for a single route. The bandwidth must be doubled for payload con-
nections in both directions. HG 1500 V3.0 supports VAD with codecs G.7231A and G.729AB.
If you use these codecs, bandwidth requirements vary in relation to the length of idle periods
in voice signals.
VLAN tagging based on IEEE 802 1q is also performed as part of the calculation. Packet length
is shorter by 4 bytes without VLAN tagging.
The overhead is calculated as follows:
Codec type Packetizing
parameters
with WBM
Sample
size (ms)
Payload
(bytes)
Ethernet
Packet length
(bytes)
Payload
packet (over-
head in per-
cent)
Ethernet
Load (incl.)
header
(Kbps)
G.711 20 20 160 230 44% 92
G.711 40 40 320 390 22% 78
G.711 60 60 480 550 15% 73.3
G.723.1 1 30 24 94 292% 25.1
G.723.1 2 60 48 118 146% 15.7
G.729A 1 20 20 90 350% 36
G.729A 2 40 40 110 175% 22
G.729A 3 60 60 130 117% 17.3
RTCP 5000 280 0.4
Table 4-1 Codec-Based Bandwidth Requirements
Protocol Bytes
RTP header 12
UDP header 8
IP header 20
802.1Q VLAN tagging 4
MAC (incl. preamble, FCS) 26
Total 70
Table 4-2 Overhead Calculation