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MaxACD Administrator Manual 187
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Enterprise VoIP Network Management
The VoIP-related aspects of a system are configured in Enterprise Manager , available
from the VoIP menu or the Windows Start menu. They include:
•
Codec Profile —create codec profiles that use different settings for jitter buffer size
and packet length. Codec profiles can be assigned to different types of VoIP
connections, as defined in the IP dialing table and IP codec assignment table.
•
VoIP Bandwidth Use —define the maximum VoIP sessions using different codecs
on a public Internet or a private intranet data pipe.
• IP Dialing Table —define IP dialing digits and codec for VoIP dialing to other
MaxACD systems or certified third-party IP devices.
•
IP Codec Table —define the codec and data pipe for IP devices and SIP trunking
service.
Understanding VoIP Bandwidth Requirements
Before starting VoIP-related configurations, it is helpful to have some understanding of
VoIP bandwidth requirements, so that you can plan your VoIP deployment properly.
The data network bandwidth required to carry VoIP depends on the following factors:
•
Codec and Compression —This is the encoding of analog voice to digital form,
decoding of digital form to analog wave form, and compression of digital form to a
smaller size. MaxACD supports three types of codec: G.711, G.729AB, G.723.1.
•
Packet Length (Frame Size) —The size of the voice frame data (payload)
transmitted in a packet. For G.711 and G.729, you have choice of 10, 20, and 30ms
lengths. For G.723.1, the packet length is a fixed 30ms. A larger packet length
decreases the transmission overhead. However, it will increase the latency and have
a negative effect on the voice quality if a packet is lost during transmission. For
G.711 and G.729, 20ms is efficient and recommended.
• IP Header —The IP/UDP/RTP header adds 40 octets per packet. With a packet
length of 20ms, the IP headers will require 16kbps of bandwidth in addition to
whatever codec is being used.
• Transmission Medium —In order to travel through the IP network, the IP packet is
wrapped in another layer by the physical transmission medium. The transmission
medium, such as Ethernet, will add its own header, checksums, and spacers to the
packet. With a packet length of 20ms, the transmission medium requires additional
15.2kbps of bandwidth to carry the packets to their destination.