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.
Summary of Contents for VSG1432-B101 - V1.10
Page 2: ......
Page 8: ...Safety Warnings VSG1432 B101 Series User s Guide 8 ...
Page 10: ...Contents Overview VSG1432 B101 Series User s Guide 10 ...
Page 20: ...Table of Contents VSG1432 B101 Series User s Guide 20 ...
Page 21: ...21 PART I User s Guide ...
Page 22: ...22 ...
Page 40: ...Chapter 2 The Web Configurator VSG1432 B101 Series User s Guide 40 ...
Page 67: ...67 PART II Technical Reference ...
Page 68: ...68 ...
Page 74: ...Chapter 5 Network Map and Status Screens VSG1432 B101 Series User s Guide 74 ...
Page 146: ...Chapter 8 Home Networking VSG1432 B101 Series User s Guide 146 ...
Page 150: ...Chapter 9 Static Routing VSG1432 B101 Series User s Guide 150 ...
Page 174: ...Chapter 11 Policy Forwarding VSG1432 B101 Series User s Guide 174 ...
Page 192: ...Chapter 12 Network Address Translation NAT VSG1432 B101 Series User s Guide 192 ...
Page 198: ...Chapter 13 Dynamic DNS Setup VSG1432 B101 Series User s Guide 198 ...
Page 224: ...Chapter 16 Firewall VSG1432 B101 Series User s Guide 224 ...
Page 230: ...Chapter 18 Parental Control VSG1432 B101 Series User s Guide 230 ...
Page 278: ...Chapter 25 Traffic Status VSG1432 B101 Series User s Guide 278 ...
Page 282: ...Chapter 26 IGMP Status VSG1432 B101 Series User s Guide 282 ...
Page 290: ...Chapter 28 Remote Management VSG1432 B101 Series User s Guide 290 ...
Page 294: ...Chapter 29 Time Settings VSG1432 B101 Series User s Guide 294 ...
Page 298: ...Chapter 30 Logs Setting VSG1432 B101 Series User s Guide 298 ...
Page 314: ...Chapter 34 Troubleshooting VSG1432 B101 Series User s Guide 314 ...
Page 344: ...Appendix A Setting up Your Computer s IP Address VSG1432 B101 Series User s Guide 344 ...
Page 354: ...Appendix B IP Addresses and Subnetting VSG1432 B101 Series User s Guide 354 ...
Page 380: ...Appendix D Wireless LANs VSG1432 B101 Series User s Guide 380 ...