A key feature of the FB2500 is the ability to bond multiple links at a per packet level. This feature is only enabled on a fully loaded model of your FB2500.

Bonding works with routing and shapers together. (See Chapter 10 for details of shapers.)

The basic principle is that you have two or more routes that are identical (same target IP prefix) and have the same localpref, so that there is nothing to decide between them. As described above this normally means one of the routes is picked.

However, where the two (or more) routes are the same type of interface, and there are shapers applied to those routes, then a decisions is made on a per packet basis as to which interface to used. The shapers are used to decide which link is least far ahead. This means that traffic is sent down each link at the speed of that link.

To make this work to the best effect, set the tx speed of the shapers on the links to match the actual link speed. E.g. for broadband lines, set the speed to match the uplink from the FB2500.

For L2TP use as an LNS, the graph created for each L2TP session has an agress speed automatically set based on the speed details sent on the L2TP connection. These can also be overridden by a RADIUS response. The effect of this is that multiple lines that are connected to the same LNS and have the same IPs routed to the lines will automatically per packet bond traffic down those lines.