Network Working Group Jon Postel RFC # 604 MITRE NIC # 21186 26 December 1973 Assigned Link Numbers This announcement modifies the official host-to-host protocol, and updates the defining documents [NIC 8246, NIC 9347]. Please note that the information on page 28 of "Host/Host Protocol for the ARPA Network" about link number assignments is updated by this note, and that a previous update [RFC 317, NIC 9347] is completely replaced. The modification is minor and should have no effect on existing network programs or usage. Four of the reserved link numbers are hereby assigned for experimental use in the testing of an internetworking protocol defined by Kahn and Cerf. Description: Control Link Link 0 is assigned for use as the host-to-host protocol control link. Data Links Links 2-71 are available for use in connections as provided by the host-to-host protocol. Internetworking Protocol Links 155-158 are to be used for experiments with the Internetworking Protocol. Measurements Links 159-191 are assigned for use in measurements under the direction of the Network Measurement Center at UCLA. Message Switching Links 192-195 are to be used for experiments with the Message Switching Protocol. Private Experiments Links 196-255 are available for private experimental use. Postel [Page 1] RFC 604 Assigned Link Numbers December 1973 Reserved Link 1, and links 72-154 are reserved for future developments and experiments and currently are not to be used. Table: Link Number Assignment 0 Control Link 1 Reserved 2-71 Connections 72-154 Reserved 155-158 Internetworking Protocol 159-191 Measurements 192-195 Message Switching Protocol 196-255 Experimental References: Host-to-host Protocol NIC 8246 Internetworking Protocol NIC 18764 Message Switching Protocol NIC 9926 [ This RFC was put into machine readable form for entry ] [ into the online RFC archives by Alex McKenzie with ] [ support from GTE, formerly BBN Corp. 10/99 ] Postel [Page 2]