Inter-Tel AXXESS - Table 2-19 Variables; Table 2-20 Required Bandwidth

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Specifications
INTER-TEL
®
AXXESS
®
MANUAL VERSION 11.0 – May 2008
Bandwidth Utilization
B. BANDWIDTH UTILIZATION
7.8 The IPRC uses all of the channels as talk paths, and signaling is transmitted via the
Ethernet interface along with the voice traffic.
7.9 To ensure enough bandwidth (i.e., the IP, Ethernet, and/or Frame Relay overhead) is
available, use the formulas listed below to calculate the amount required to make inter-node
IPRC calls. Although bandwidth varies depending upon call control messages, tone detection,
voice activity detection (VAD), and the RTP profile, these formulas provide a good estimate
for planning the network.
NOTE: The amount of bandwidth used on any network segment (i.e., WAN or LAN) should
never exceed 75% of the available bandwidth. There should always be a 25% margin factored
in when planning the network capacity for voice, data, etc.
7.10 The bandwidth is calculated based on the following programmable settings:
• Vocoder (voice codec): Determines the codec bandwidth and the frame size (audio
sample size).
• Audio Frames per IP Packet: Determines the number of voice frames placed into each
packet.
• RTP Profile: Determines the Real-time Transport Protocol (RTP) header size.
7.11 The specific variables in the formula are defined in the following table.
7.12 While the maximum burst data per call (BurstDataPerCall) varies from system to sys-
tem, you can estimate the bandwidth required based on the values in the following table.
Table 2-19. Variables
Variable Value
RTPHeadSize 4 for Inter-Tel RTP; 12 for Standard RTP
IP/UDPHeadSize 28 bytes
EthHeadSize 18 bytes
FrameHeadSize 6 bytes (worst case)
AudioFramesPerIPPacket Number of voice frames used per packet
VoiceFrameSize Size, in milliseconds, for one voice frame, which is dependent
on the voice codec (vocoder)
CodeBW Codec bandwidth (in kbps)
BurstDataPerCall Data bursts in the call control socket for each call setup
BurstDataDB 200 kbps when importing/exporting in DB Programming
#Calls Number of calls
Table 2-20. Required Bandwidth
Event KBPS
IC Call 10
All-Ring Hunt Group Call 10 per member