Atm Qos; Traffic Shaping; Atm Traffic Classes - ZyXEL Communications IES-1248-51V User Manual

Chapter 17 xDSL Profiles Setup
Table 26 Port Profile (continued)
LABEL
Down Shift SNR
Add
Cancel

17.2 ATM QoS

ATM Quality of Service (QoS) mechanisms provide the best service on a per-flow
guarantee. ATM network infrastructure was designed to provide QoS. It uses fixed
cell sizes and built-in traffic management (see
allows you to fine-tune the levels of services on the priority of the traffic flow.

17.3 Traffic Shaping

Traffic shaping is an agreement between the carrier and the subscriber to regulate
the average rate and fluctuations of data transmission over an ATM network. This
agreement helps eliminate congestion, which is important for transmission of real
time data such as audio and video connections.
Note: Traffic shaping controls outgoing (downstream) traffic, not incoming (upstream).

17.3.1 ATM Traffic Classes

These are the basic ATM traffic classes defined by the ATM Forum Traffic
Management 4.0 Specification.
17.3.1.1 Constant Bit Rate (CBR)
Constant Bit Rate (CBR) is an ATM traffic class that provides fixed bandwidth. CBR
traffic is generally time-sensitive (doesn't tolerate delay). CBR is used for
connections that continuously require a specific amount of bandwidth. Examples
of connections that need CBR would be high-resolution video and voice.
154
DESCRIPTION
The downstream down shift signal to noise margin (0-31 dB). When
the channel's signal to noise margin goes below this number, the
device shifts to a lower transfer rate. Configure the downstream down
shift signal to noise margin to be less than or equal to the target
downstream signal to noise margin and greater than or equal to the
minimum downstream signal to noise margin.
Click Add to save your changes to the IES's volatile memory. The IES
loses these changes if it is turned off or loses power, so use the
Config Save link on the navigation panel to save your changes to the
non-volatile memory when you are done configuring.
Click Cancel to start configuring the screen again.
Section 17.3 on page
IES-1248-51V User's Guide
154). This