| |
Using PPP Multilink is, in itself, an optimization of PPP connections. You may obtain additional bandwidth by increasing the member links in a PPP Multilink group. There are two ways to do this, static and bandwidth-on-demand.
If you choose static, every time a connection is made the number of member links assigned to the multilink group are used. This can be costly, but it does provide immediate bandwidth. However, you pay a price for this performance optimization in the cost of your line use. You might not be using all of the bandwidth available, thereby wasting the unused bandwidth.
Bandwidth-on-demand offers the benefit of increasing bandwidth (when needed) by activating another line in the multilink group when the utilization of the first line exceeds the value set in the Bandwidth Threshold Level.
When using bandwidth-on-demand, the server monitors the utilization of the first line connection over the period of time set in Bandwidth Measurement Time field. The default value is set at 30 seconds. If the utilization of the line exceeds the Bandwidth Threshold Level at any time during that 30 seconds, the next line in the multilink group is activated, and both lines share transfers to the PPP connection. (The splitting of packets and overhead is done at the PPP level, and the multilink connection is perceived as a single connection by network protocols such as IP or IPX.)
If a multilink group is configured for three or more lines and the average utilization of the two lines exceeds the Bandwidth Threshold Level during the next measurement period (for example, the next 30 seconds), another line would be activated.
If, however, during the subsequent measuring period, the average utilization of the active member links were to be below the Bandwidth Threshold Level, the most recently activated line would drop out of the connection.
If you decide that the increased performance is required, you have to experiment and monitor the performance of the multilink group to decide on the bandwidth threshold level at which to trigger the connection of another line and the total number of member links to include in the multilink group.
| |