Network Working Group J. T. Korb
Request for Comments: 877 Purdue University
A Standard for the Transmission of IP Datagrams
Public Data Networks
This RFC specifies a standard adopted by CSNET, the VAN gateway, and
other organizations for the transmission of IP datagrams over the
X.25-based public data networks.
An X.25 virtual circuit is opened on demand when a datagram arrives at
the network interface for transmission. A virtual circuit is closed
after some period of inactivity (the length of the period depends on
the cost associated with an open virtual circuit). A virtual circuit
may also be closed if the interface runs out of virtual circuits. An
algorithm for managing virtual circuits during peak demand is given
virtual circuits to a single site. Sites should attempt to
handle such incoming calls gracefully: transmit on the
additional circuits if possible and accept incoming datagrams
from them, but do not accept the CALL REQUEST, only to
immediately close the connection or ignore datagrams
transmitted on such circuits.
 Comer, D.E. and Korb, J.T., "CSNET Protocol Software: The
IP-to-X.25 Interface", SIGCOMM Symposium on Communications
Architectures and Protocols, March 1983.
Korb [Page 2]