Frame expansion moves forward

* IEEE group looking at Ethernet frame expansion becomes a task force

The IEEE group studying the possibility of expanding the size of Ethernet frames has taken the next step: it has become a task force.

That means that the group must have finished its debate over whether the expansion should be done at all - and has decided to move ahead with creating a standard. The task force has received the designation IEEE 802.3as. A “possible timeline (not adopted)” on the group’s Web site shows a standard being reached this October.

The group has not yet decided what the new, expanded maximum length of Ethernet frames should be. According to material on its Web site, the group is considering lengths ranging from 1,875 bytes to 2,048 bytes. As I noted over the summer, the IEEE 802.1 group had requested frame size in the range of 1,650 bytes to 2,048 bytes.

Today’s Ethernet frames are 1,518 bytes, maximum. The maximum length for the data field will continue to be 1,500 bytes, so expanding the header and footer information - the overhead - is all that is really under discussion. The group says it will preserve the basic frame format.

Some portion of the expanded frames would likely be reserved for “future use.” As the group notes, building in a little bit extra would help to reduce the chance that the maximum frame size would have to be expanded again in the future. That’s especially important since so much rides on top of Ethernet these days, and changing frame sizes is not something the IEEE would want to do very often at all.

Learn more about this topic

Time for frame expansion?IEEE 802.3as

Network World High Speed LANs Newsletter, 07/20/04

Frame Expansion Task Force


Copyright © 2005 IDG Communications, Inc.

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