From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <3.0.6.32.20011122115008.00974e88@pop3.clear.net.nz> To: 9fans@cse.psu.edu From: Andrew Simmons Subject: Re: [9fans] Private Namespaces for Linux In-Reply-To: <3.0.5.32.20011121124821.019d46d0@mail.real.com> References: <20011121145219.5E53D199E7@mail.cse.psu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Date: Thu, 22 Nov 2001 11:50:08 +1300 Topicbox-Message-UUID: 271a64fa-eaca-11e9-9e20-41e7f4b1d025 >To ask a rude question then, what was the original need or rationale for >inventing IL? > The original rationale in http://plan9.bell-labs.com/sys/doc/il/il.pdf reads as follows: None of the standard IP protocols [RFC791] is suitable for transmission of 9P messages over an Ethernet or the Internet. TCP [RFC793] has a high overhead and does not preserve delimiters. UDP [RFC768], while cheap and preserving= message delimiters, does not provide reliable sequenced delivery. When we were implementing IP, TCP, and UDP in our system we tried to choose a protocol suitable for carrying 9P. The properties we desired were: =A1 Reliable datagram service =A1 In-sequence delivery =A1 Internetworking using IP =A1 Low complexity, high performance =A1 Adaptive timeouts No standard protocol met our needs so we designed a new one, called IL (Internet Link). Maybe the TCP overhead isn't as bad in practice as originally feared.