Some of the terms related to Ethernet should be clarified, I believe. The IEEE 802.3 standard does not recognize the terms 'jumbo' or 'superjumbo'. These are as you point out of the standard. The max frame size in the original Ethernet standard was 1518. This was slightly increased about a decade ago to 1522 when IEEE 802.1 added four bytes for VLAN ID. More recently the IEEE 802.3as extended the max size of the Ethernet frame to 2048. Also, there is no such thing as a 'extra large Ethernet header'. The header of an Ethernet frame is of fixed size. It is the payload in the Ethernet frame that may be of variable length.
Dan > -----Original Message----- > From: Matt Mathis [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 01, 2007 5:35 PM > To: Internet Area > Subject: Re: [Int-area] What is a jumbogram, was: Larger MTUs > > Jumbo just means larger than standard. Given that there are > so many standards to choose from... well you get the idea. > > To add to the confusion, to IEEE 802.3, jumbo means 1536 (I > think I got the number right). This is for extra large > Ethernet headers with a 1500 byte payload. They use > "superjumbo" to refer to 9kB, etc. > > It is really important that we do not standardize 9k or any > other fixed MTU as the new Internet cell size. The intent of > 4821 was to permit the Internet to support diverse MTUs at > all scales. With a couple of additional clicks on Moore's > Law 9k is likely to be deemed too small, but we really don't > want to have to do any part of this over again. > > BTW for some background on the wider problem check out > http://www.psc.edu/~mathis/MTU > > THanks, > --MM-- > ------------------------------------------- > Matt Mathis http://www.psc.edu/~mathis > Work:412.268.3319 Home/Cell:412.654.7529 > ------------------------------------------- > Evil is defined by mortals who think they know "The Truth" > and use force to apply it to others. > > > > _______________________________________________ > Int-area mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/int-area > _______________________________________________ Int-area mailing list [email protected] https://www1.ietf.org/mailman/listinfo/int-area
