RFC 308 (rfc308) - Page 1 of 4
ARPANET host availability data
Alternative Format: Original Text Document
Network Working Group Marc Seriff Request for Comments 308 MIT-DMCG NIC 9259 13 MARCH 1972 References: RFC 254 ARPANET HOST AVAILABILITY DATA Several months ago a SURVEY program was implemented on the MIT-DMCG ITS PDP-10 system to aid in gathering information on the availability of various HOSTS on the ARPANET. The purpose of this Request for Comments is threefold: 1. to inform the Network Working Group of the existence of this information gathering service and about getting access to it, 2. to present the results of SURVEY for its first few months, and 3. to correct errors in our data or collection methods. Briefly, the SURVEY program works as follows: At 15-minute intervals whenever the MIT-DMCG ITS Time-Sharing system is in normal operation, a SURVEY is started. The SURVEY program attempts to establish a connection to the LOGGER (socket 1) of each HOST listed in its table. The results of each connection attempt are recorded for future reference. The Initial Connection Protocol is aborted prior to reading the transmitted socket number so as to cause the minimum amount of processing at SURVEYed HOSTS. If the LOGGER connection succeeds, the average request-for connection response time (in seconds) for the HOST is updated. This information can later be viewed in several formats using the MIT-DMCG server TELNET "NETWRK" as described below. Each test results in the assignment of one of the following five statuses: 1. LOGGER available - connection completed. 2. LOGGER not responding - RFC sent (HOST-HOST OK), but no response (20 seconds allowed). 3. LOGGER rejecting - CLOSE returned by NCP. 4. NCP not responding - RESET timed out (15 seconds allowed). 5. HOST dead - host-dead status returned by IMP.
