Prestige 100 and 100IH ISDN Router and Router/Hub
4.1.3 PPP 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.
4.1.4 Bandwidth 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 4-2 BTR v MTR for BOD
BTR & MTR Setting
No. of channel(s) used
Max No. of channel(s) used
Bandwidth on demand
BTR = 64, MTR = 64 | 1 | 1 | Off |
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BTR = 64, MTR = 128 | 1 | 2 | On |
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BTR = 128, MTR = 128 | 2 | 2 | Off |
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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
Remote Node Configuration |