RFC 979 (rfc979) - Page 1 of 15
PSN End-to-End functional specification
Alternative Format: Original Text Document
Network Working Group Andrew G. Malis
Request for Comments: 979 BBN Communications Corp.
March 1986
PSN END-TO-END FUNCTIONAL SPECIFICATION
Status of this Memo
This memo is an updated version of BBN Report 5775, "End-to-End
Functional Specification". It has been updated to reflect changes
since that report was written, and is being distributed in this form
to provide information to the ARPA-Internet community about this
work. The changes described in this memo will affect AHIP (1822
LH/DH/HDH) and X.25 hosts directly connected to BBNCC PSNs.
Information concerning the schedule for deployment of this version of
the PSN software (Release 7.0) in the ARPANET and the MILNET can be
obtained from DCA. Distribution of this memo is unlimited.
1 Introduction
This memo contains the functional specification for the new BBNCC PSN
End-to-End (EE) protocol and module (PSN stands for Packet Switch
node, and has previously been known as the IMP). The EE module is
that portion of the PSN code which is responsible for maintaining EE
connections that reliably deliver data across the network, and for
handling the packet level (level 3) interactions with the hosts. The
EE protocol is the peer protocol used between EE modules to create,
maintain, and close connections. The new EE is being developed in
order to correct a number of deficiencies in the old EE, to improve
its performance and overall throughput, and to better equip the PSN
to support its current and anticipated host population.
The initial version of the new EE is being fielded in PSN Release
7.0. Both the old and new EEs are resident in the PSN code, and each
PSN may run either the old or the new EE (but not both) at any time,
under the control of the Network Operations Center (NOC). The NOC
has facilities for switching individual PSNs or the entire network
between the old and new EEs. When the old EE is running, PSN 7.0's
functionality is equivalent to that provided by PSN 6.0, and the
differences listed in this memo do not apply. Hosts on PSNs running
the old EE cannot interoperate with hosts on PSNs running the new EE.
There are two additional sections following this introduction.
Section two describes the motivation and goals driving the new EE
project.
Section three contains the new EE's functional specification. It
describes the services provided to the various types of hosts that
Malis