ZyXEL 202H 91-003-194001B Manual Do Utilizador

P-202H Plus v2 User’s Guide

Chapter 20 Remote Node Configuration

190

The ZyXEL Device uses the PPP Multilink Protocol (PPP/MP) to bundle multiple links in a 
single connection to boost the effective throughput between two nodes.

Due to the fragmentation/reconstruction overhead associated with MP, you may not get a 
linear increase in throughput when a link is added.

The number of links in an MP bundle can be statically configured, or dynamically determined 
at runtime, as explained in the following section.

The Bandwidth on Demand (BOD) feature adds or subtracts links dynamically according to 
traffic demand. After the initial call, the ZyXEL Device uses BAP (Bandwidth Allocation 
Protocol) to ask the peer for additional telephone number if BACP (Bandwidth Allocation 
Control Protocol) is negotiated. Otherwise, the ZyXEL Device uses the statically configured 
(primary and secondary) telephone numbers of the remote node.

The configuration of bandwidth on demand focuses on the Base Transmission Rate (BTR) and 
the Maximum Transmission Rate (MTR). The relationship between BTR and MTR are shown 
in the following table:

When bandwidth on demand is enabled, a second channel will be brought up if traffic on the 
initial channel is higher than the high Target Utility number for longer than the specified Add 
Persist value. Similarly, the second channel will be dropped if the traffic level falls below the 
low Target Utility number for longer than the Subtract Persist value.

The Target Utility specifies the line utilization range at which you want the ZyXEL Device to 
add or subtract bandwidth. The range is 30 to 64 Kbps (kilobits per second). The parameters 
are separated by a '-'. For example, '30-60' means the add threshold is 30 Kbps and subtract 
threshold is 60 Kbps. The ZyXEL Device performs bandwidth on demand only if it initiates 
the call. Addition and subtraction are based on the value set in the BOD Calculation field. If 
this field is set to Transmit or Receive, then traffic in either direction will be included to 
determine if a link should be added or dropped. Transmit will only use outgoing traffic to 
make this determination and Receive will only use incoming traffic to make this 
determination.

Table 65   BTR vs MTR for BOD

BTR = 64, MTR = 64

1

1

Off

BTR = 64, MTR = 128

1

2

On

BTR = 128, MTR = 128

2

2

Off