New Multi-Point Link Aggregation: Under construction

Until recently, trunking (a.k.a. IEEE 802.3ad Link Aggregation) has been limited to point-to-point connections. However, a newly emerging trunking protocol is currently under development that stands to change that. It's called Multi-Point Link Aggregation (MPLA), and it allows the trunking of several links into one logical link. The difference between MPLA and traditional Link Aggregation is that MPLA allows the trunk to span multiple switches and traverse divergent network paths.

Moreover, traditional Link Aggregation provides a level of fault tolerance by automatically redirecting traffic around a failed link. However, since it's restricted to adjacent devices, it has no way to recover from the complete failure of a switch. By contrast, MPLA allows the link to recover from a switch failure by redirecting traffic to a completely different network path.

With MPLA, network managers can leverage the increased speed of traditional Link Aggregation with the high redundancy of parallel network paths to create a high-performance fault-tolerant network.

Now for a reality check: To date, no vendors have actually delivered MPLA devices, and the first products are expected to appear this quarter - providing, of course, that MPLA vendors actually meet their projected delivery schedules. To make matters worse, the complexity of the technology is likely to make interoperability challenging, at best.

In the end, multi-vendor MPLA deployment is not likely much before the end of 1999. Still, as the saying goes, "Anything worth having is worth waiting for."

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