NEC SL1100
Issue 6.0
Networking Manual
6 - 13
5.2
Bandwidth
The bandwidth required for VoIP calls depends on several factors, including:
Number of simultaneous calls
CODEC used
Frame Size
Data Networking Protocol used
The more frames encapsulated into each packet, the less bandwidth is
required. This is because each packet transmitted has the same header size.
Therefore, if numerous very small packets are sent then bandwidth is also
being used for a large amount of header information. If we add several frames
to the packet, less packets are transmitted and therefore have less header
information sent.
If we add many voice frames to each packet, less bandwidth is being used.
However, this does have disadvantages. If there is a large packet size, and a
particular voice packet is lost, this has a greater impact on the speech quality.
If a small quantity of voice frames per packet is being used, the effect of losing
a packet is reduced.
As a general rule: The more frames per packet, the less bandwidth is used,
but the quality is also lower.
Examples:
Example 1: CODEC: G.729 Frame Size: 10ms Voice Frames per Packet: 2
Voice Sample Size: 20ms (frame size x Voice Frames) Bandwidth Required:
24Kbps
Example 2: CODEC: G.729 Frame Size: 80ms Voice Frames per Packet: 8
Voice Sample Size: 80ms (frame size x Voice Frames) Bandwidth Required:
12Kbps
S
ECTION
6
Q
UALITY
OF
S
ERVICE
(Q
O
S) I
MPLEMENTATION
Section
2.2 Voice Quality Improvements on page 6-3
discusses some of the problems
associated with voice quality. This section describes how QoS can be implemented
on data networks to provide the “best case” for VoIP traffic.
Summary of Contents for SL1100
Page 1: ...Networking Manual NDA 31190 Issue 6 0 SL1100...
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Page 62: ...Issue 6 0 NEC SL1100 5 30 Programming THIS PAGE INTENTIONALLY LEFT BLANK...
Page 94: ...Issue 6 0 NEC SL1100 6 32 Network Design Considerations THIS PAGE INTENTIONALLY LEFT BLANK...
Page 134: ...Issue 6 0 NEC SL1100 8 10 DHCP Client THIS PAGE INTENTIONALLY LEFT BLANK...
Page 159: ...NEC SL1100 Issue 6 0 Networking Manual 9 25 Figure 9 7 Log In to IP Phone...
Page 181: ...NEC SL1100 Issue 6 0 Networking Manual 9 47 Figure 9 25 IP System Operation Setup...
Page 206: ...Issue 6 0 NEC SL1100 9 72 IP Multiline Station SIP Figure 9 36 NAPT Configuration Example...
Page 230: ...Issue 6 0 NEC SL1100 10 18 IP Single Line Telephone THIS PAGE INTENTIONALLY LEFT BLANK...
Page 232: ...Issue 6 0 NEC SL1100 11 2 NAPT Figure 11 1 NAPT Configuration Example...
Page 242: ...Issue 6 0 NEC SL1100 12 4 All DSP Busy Indication THIS PAGE INTENTIONALLY LEFT BLANK...
Page 290: ...Issue 6 0 NEC SL1100 13 48 SL Net THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 292: ...SL1100 Networking Manual NEC Corporation of America Issue 6 0...