Atm Qos; Traffic Shaping - ZyXEL Communications IES-1248 VDSL-SWITCH User Manual

IES-1248 User's Guide
LABEL
Min SNR (db) Type the minimum downstream signal to noise margin (0-31 dB). Configure the minimum
Target SNR (db) Type the target downstream signal to noise margin (0-31 dB). Configure the target
Add
Cancel
11.11

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 the
following section on traffic shaping). This allows you to fine-tune the levels of services on the priority of the traffic
flow.
11.12

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.
11.12.1 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) 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.
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 (rt-VBR) or non-real time (nrt-VBR) connections.
11-14
Table 11-5 Port Profile
downstream signal to noise margin to be less than or equal to the maximum downstream
signal to noise margin.
downstream signal to noise margin to be greater than or equal to the minimum
downstream signal to noise margin and less than or equal to the maximum downstream
signal to noise margin.
Click Add to save your changes to the IES-1248's volatile memory. The IES-1248 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.
DESCRIPTION
ADSL Port Setup