The All-New Switch Book: The Complete Guide to LAN Switching Technology, Second Edition

9.5. IEEE 802.3ad Link Aggregation Standard

IEEE 802.3ad is the official standard for Link Aggregation [IEEE99b]. The explanation of aggregation presented in this chapter is consistent with both the model of operation and the formal description in the standard. However, the usual caveats apply — this chapter is not intended as a replacement for the standard and does not attempt to present all of the formal compliance requirements and specifications of the standard itself. Readers responsible for developing standards-compliant products can use this book as a guide, but should refer to the official documents for specific conformance requirements.

Initial presentations and discussions relating to link aggregation occurred at an IEEE standards meeting in November 1997. The IEEE 802.3ad Task Force first officially met in July 1998. By July 1999, a draft standard was ready for formal balloting; final approval of the standard occurred in 2000.

9.5.1. Scope of the Standard

There is always a tradeoff to be made between specifying a standard with wide applicability and getting the work completed in a timely manner. Defined too narrowly, a standard has limited usefulness. Defined too broadly, it may take so long for the specifications to be agreed on that proprietary solutions (with a narrower scope) will become widely deployed, making the standard moot. IEEE 802.3ad specifies a method for vendor-interoperable link aggregation under the following constraints:

• The standard applies exclusively ...