Network Configuration Concepts
211
Bandwidth management and call admission control can be used to ensure that voice quality is
maintained in parts of the network where there may be bandwidth constraints. For details, refer
to “Bandwidth, Bandwidth Management, Codecs and Compression” on page 171.
Refer to the
3300 ICP
Resiliency
guide for detailed calculations and breakdown of signalling
messages for different connections.
SERIALIZATION DELAY
Serialization delay happens because data is queued in a particular device, but cannot be sent
because another packet is currently being sent. In a fast link, such as in the LAN, the delay is
fairly small (a few milliseconds) and is easily resolved with the end-device jitter buffer.
However, in a WAN access connection, the data rate is not as high as within the LAN. In this
case, the waiting delay increases as the data rate reduces. If a particularly large packet (for
example, 1500 bytes) is being sent, then other devices must wait until it has gone before they
can gain access.
The IP phone and gateway devices are capable of handling delay variations (jitter) up to high
limits. However, in order to maintain the best voice quality performance, this variation should
be kept below 30 ms, with an ideal limit of 20 ms. The following figure shows waiting delay
against link speed, as well as against maximum transmission units (MTU). The value for MTU
can be programmed in routers so that packets with a payload greater than this number can be
reduced in size. The graph shows that when a packet of 1500 bytes is sent, a data-rate of about
700 kbps is needed on the WAN link in order to meet the ideal 20 ms limit.
Figure 29: Serialization delay Frame Relay
Содержание MiVOICE BUSINESS
Страница 1: ...Mitel MiVoice Business RELEASE 7 2 ENGINEERING GUIDELINES ...
Страница 15: ...Chapter 1 ABOUT THIS DOCUMENT ...
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Страница 22: ...Engineering Guidelines 8 ...
Страница 23: ...Chapter 2 SYSTEM OVERVIEW ...
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Страница 28: ...Engineering Guidelines 14 ...
Страница 29: ...Chapter 3 TYPICAL CONFIGURATIONS ...
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Страница 73: ...Chapter 4 PHONES AND VOICE APPLICATIONS ...
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Страница 95: ...Phones and Voice Applications 81 Figure 9 ICP Connection Paths and Limitations ...
Страница 100: ...Engineering Guidelines 86 ...
Страница 101: ...Chapter 5 POWER ...
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Страница 129: ...Chapter 6 PERFORMANCE ...
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Страница 135: ...Chapter 7 APPLICATIONS ...
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Страница 142: ...Engineering Guidelines 128 ...
Страница 143: ...Chapter 8 EMERGENCY SERVICES ...
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Страница 151: ...Chapter 9 IP NETWORKING ...
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Страница 167: ...Chapter 10 LICENSING ...
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Страница 183: ...Chapter 11 BANDWIDTH CODECS AND COMPRESSION ...
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Страница 209: ...Chapter 12 NETWORK CONFIGURATION CONCEPTS ...
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Страница 245: ...Chapter 13 NETWORK CONFIGURATION SPECIFICS ...
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Страница 309: ...Appendix A CAT 3 WIRING ...
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Страница 315: ...CAT 3 Wiring 301 Figure 55 CX MX MXe AX and LX Minimum Cable Standard ...
Страница 316: ...Engineering Guidelines 302 ...
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Страница 335: ...Appendix C LLDP AND LLDP MED CONFIGURATION EXAMPLES ...
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Страница 347: ...Appendix D VOIP AND VLANS ...
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Страница 353: ...Appendix E VOIP SECURITY ...
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