User`s guide

Chapter 8 WAN Setup
P-2602HWUDL-D User’s Guide
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8.3.1.2 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.
8.3.1.3 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.
8.4 Zero Configuration Internet Access
Once you turn on and connect the ZyXEL Device to a telephone jack, it automatically detects
the Internet connection settings (such as the VCI/VPI numbers and the encapsulation method)
from the ISP and makes the necessary configuration changes. In cases where additional
account information (such as an Internet account user name and password) is required or the
ZyXEL Device cannot connect to the ISP, you will be redirected to web screen(s) for
information input or troubleshooting.
Zero configuration for Internet access is disabled when
• the ZyXEL Device is in bridge mode
• you set the ZyXEL Device to use a static (fixed) WAN IP address.
8.5 Internet Access Setup
Use this screen to change your ZyXEL Device’s WAN remote node settings. Click Network >
WAN > Internet Access Setup. The screen differs by the encapsulation you select.
See Section 8.1 on page 127 for more information.