ZyXEL Communications 1001H manual PPP Multilink, Bandwidth on Demand, BTR v MTR for BOD

P100IH ISDN Router

successful authentication, please make sure that you specify the correct authentication protocol when connecting to such an implementation.

5.1.4PPP Multilink

The Prestige 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.

5.1.5Bandwidth on Demand

The Bandwidth on Demand (BOD) feature adds or subtracts links dynamically according to traffic demand. After the initial call, the Prestige uses BAP (Bandwidth Allocation Protocol) to ask the peer for additional telephone number if BACP (Bandwidth Allocation Control Protocol) is negotiated. Otherwise, the Prestige 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 below:

Table 5-2 BTR v MTR for BOD

BTR & MTR Setting	No. of	Max No. of	Bandwidth
	channel(s)	channel(s)	on demand
	used	used
BTR = 64, MTR = 64	1	1	Off
BTR = 64, MTR = 128	1	2	On
BTR = 128, MTR = 128	2	2	Off

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 Prestige 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 Prestige 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

5-6 Remote Node Configuration