I'm with Priscilla 110% on this one. Although a lot of folks want to get real scientific on terminology, I try to stick to the basics. In terms of Internet speak on TCP/IP, my ultimate reference is TCP/IP Illustrated by the late W. Richard Stevens. He says on page 9, "The unit of data that TCP sends to IP is called a TCP segment. The unit of data that IP sends to the network interface is called an IP datagram. The stream of bits that flows across the Ethernet is called a frame...We could draw a nearly identical picture for UDP data. The only changes are that the unit of information that UDP passes to IP is called a UDP datagram" That says it all. I don't know if it helps any, but the original IP RFC (760) defines a TCP protocol data unit as a "segment". In a related note, the original RFC for TCP quotes no less than 200+ instances of referencing TCP as "segments". Also, the original RFC specification for UDP (768) makes reference to datagrams only. There is no mention of segments. On a semi-related note, Cisco maintains an Internetworking terms and glossary section on CCO. They have correctly stated, "segment -3. Term used in the TCP specification to describe a single transport layer unit of information." Unfortunately in several instances of Cisco courseware they have erroneously referred to a segment as both TCP and UDP, which in my humble opinion is wrong. Of course, one must ever be mindful of the old axiom: There's the right way, the wrong way, and the Cisco way :-) HTH, Paul Werner p.s. To add to your well researched list below, oddly Novell refers to SPXII as "messages". IPX is of course referenced as datagrams. > I have been excluded once again from the list, but this may get through > at > some point. > > I checked Banyan VINES and it doesn't use the term segment for the Inter > > Process Communications (IPC) protocol which provides both datagram and > reliable message delivery service. VINES doesn't use segment for the > Sequenced Packet Protocol (SPP) either, which provides a reliable > virtual > connection service. See: > > http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/vines.h tm > > AppleTalk Transaction Protocol (ATP) doesn't use the term "segment." > Neither does the AppleTalk Datastream Protocol (ADSP). They are both > connection-oriented transport-layer protocols. > > NetWare Core Protocol (NCP) doesn't use "segment." Neither does NetWare > Sequenced Packet Exchange (SPX). > > Some descriptions of the DECnet Network Services Protocol (NSP) use > "segment." Most descriptions of NSP do not use the term. See > http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/decnet. htm > > A quick look at Tannenbaum, who does a nice job with generic but > technical > descriptions of the layers in his quintessential "Computer Networks," > found > no use of the word segment. He uses the OSI term Transport Protocol Data > > Unit (TPDU) and the term "message." > > Which reminds me, OSI does not use the term segment. It's mostly just > TCP > and it is an unfortunate word to use because segment has many other > meanings, such as LAN segment, a segment of memory, etc. ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=18741&t=18702 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
