With its focus on interoperability and the minimization of complexity, Ethernet networks continue to be plug-and-play, supporting large multi-vendor deployments with reliable auto-detection and auto-negotiation. This tradition continues in the new IEEE 802.3ah standards for Ethernet-over-copper, including 2BASE-TL. One particularly interesting feature is the ability to auto-detect which pairs are connected between two devices and are, therefore, eligible to be aggregated into a single Ethernet connection. Using this bonding auto-detection, carriers are not forced to configure the cross-connect information on each device. Instead, an IEEE 802.3ah-capable switch exchanges information to negotiate which pairs are connected to the same remote system, and then creates an aggregate port from those pairs. Pairs can even come and go, being added and removed dynamically, without affecting the operational status of the aggregate port.

Another major improvement over traditional IMA, with best-in-class 2BASE-TL bonding involves the utilization of each pair at its maximum rate, making the aggregate truly the sum of its parts. The IEEE 802.3ah interfaces introduce an aggregation multiplexing and de-multiplexing layer into the Ethernet stack that is responsible for taking an Ethernet frame and partitioning it over multiple variable speed links in a manner that best utilizes the speed of each pair. For example, an implementation could partition a frame into variable size fragments, where the size of the fragments depends upon the speed of the link, with the faster links carrying the larger fragments.

In addition to efficiency, the Ethernet-over-copper technologies of IEEE 802.3ah establish a multi-vendor foundation for frame-optimized access networks. In effect, these new technologies provide a better path to simplicity and interoperability in the network. IEEE 802.3ah is a pure carrier-grade Ethernet technology and, therefore, eliminates the complex translation and interworking functions that were previously required when taking the customers’ frames, translating them into ATM cells in the access network, and then re-translating them back into frames for the next-hop router or switch.