Chapter 6 Broadband
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6.3.7 ATM Traffic Classes
These are the basic ATM traffic classes defined by the ATM Forum Traffic
Management 4.0 Specification.
Constant Bit Rate (CBR)
Constant Bit Rate (CBR) provides fixed bandwidth that is always available even if
no data is being sent. CBR traffic is generally time-sensitive (doesn't tolerate
delay). CBR is used for connections that continuously require a specific amount of
bandwidth. A PCR is specified and if traffic exceeds this rate, cells may be
dropped. Examples of connections that need CBR would be high-resolution video
and voice.
Variable Bit Rate (VBR)
The Variable Bit Rate (VBR) ATM traffic class is used with bursty connections.
Connections that use the Variable Bit Rate (VBR) traffic class can be grouped into
real time (VBR-RT) or non-real time (VBR-nRT) connections.
The VBR-RT (real-time Variable Bit Rate) type is used with bursty connections that
require closely controlled delay and delay variation. It also provides a fixed
amount of bandwidth (a PCR is specified) but is only available when data is being
sent. An example of an VBR-RT connection would be video conferencing. Video
conferencing requires real-time data transfers and the bandwidth requirement
varies in proportion to the video image's changing dynamics.
The VBR-nRT (non real-time Variable Bit Rate) type is used with bursty
connections that do not require closely controlled delay and delay variation. It is
commonly used for "bursty" traffic typical on LANs. PCR and MBS define the burst
levels, SCR defines the minimum level. An example of an VBR-nRT connection
would be non-time sensitive data file transfers.
Unspecified Bit Rate (UBR)
The Unspecified Bit Rate (UBR) ATM traffic class is for bursty data transfers.
However, UBR doesn't guarantee any bandwidth and only delivers traffic when the
network has spare bandwidth. An example application is background file transfer.
6.3.8 Introduction to VLANs
A Virtual Local Area Network (VLAN) allows a physical network to be partitioned
into multiple logical networks. Devices on a logical network belong to one group. A
device can belong to more than one group. With VLAN, a device cannot directly
talk to or hear from devices that are not in the same group(s); the traffic must
first go through a router.
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Страница 8: ...Safety Warnings VSG1435 B101 Series User s Guide 8 ...
Страница 10: ...Contents Overview VSG1435 B101 Series User s Guide 10 ...
Страница 20: ...Table of Contents VSG1435 B101 Series User s Guide 20 ...
Страница 21: ...21 PART I User s Guide ...
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Страница 42: ...Chapter 2 The Web Configurator VSG1435 B101 Series User s Guide 42 ...
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Страница 78: ...Chapter 5 Network Map and Status Screens VSG1435 B101 Series User s Guide 78 ...
Страница 150: ...Chapter 8 Home Networking VSG1435 B101 Series User s Guide 150 ...
Страница 154: ...Chapter 9 Static Routing VSG1435 B101 Series User s Guide 154 ...
Страница 178: ...Chapter 11 Policy Forwarding VSG1435 B101 Series User s Guide 178 ...
Страница 196: ...Chapter 12 Network Address Translation NAT VSG1435 B101 Series User s Guide 196 ...
Страница 202: ...Chapter 13 Dynamic DNS Setup VSG1435 B101 Series User s Guide 202 ...
Страница 228: ...Chapter 16 Firewall VSG1435 B101 Series User s Guide 228 ...
Страница 234: ...Chapter 18 Parental Control VSG1435 B101 Series User s Guide 234 ...
Страница 282: ...Chapter 25 Traffic Status VSG1435 B101 Series User s Guide 282 ...
Страница 286: ...Chapter 26 IGMP Status VSG1435 B101 Series User s Guide 286 ...
Страница 294: ...Chapter 28 Remote Management VSG1435 B101 Series User s Guide 294 ...
Страница 298: ...Chapter 29 Time Settings VSG1435 B101 Series User s Guide 298 ...
Страница 302: ...Chapter 30 Logs Setting VSG1435 B101 Series User s Guide 302 ...
Страница 318: ...Chapter 34 Troubleshooting VSG1435 B101 Series User s Guide 318 ...
Страница 348: ...Appendix A Setting up Your Computer s IP Address VSG1435 B101 Series User s Guide 348 ...
Страница 358: ...Appendix B IP Addresses and Subnetting VSG1435 B101 Series User s Guide 358 ...
Страница 368: ...Appendix C Pop up Windows JavaScripts and Java Permissions VSG1435 B101 Series User s Guide 368 ...
Страница 384: ...Appendix D Wireless LANs VSG1435 B101 Series User s Guide 384 ...
Страница 412: ...Index VSG1435 B101 Series User s Guide 412 ...