6-Sep-82 16:30:41-PDT,2623;000000000001 Mail-from: ARPANET host SRI-NIC rcvd at 6-Sep-82 1630-PDT Date: 6 Sep 1982 1521-PDT From: Nic at SRI-NIC Subject: Network News No. 14 - Please Read - Important Announcement!! To: ANEWS-DIST: cc: NIC-STAFF: ===================================================================== ANEWS-14 DCA Code B645 6 August 1982 (DCACODE252@ISI) (202) 692-6175/6 DoD NETWORK NEWSLETTER ===================================================================== ATTENTION! - Netwide TCP Experiment - October 1, 1982 --------------------------------------------------------------------- On October 1, from 12:00 to 16:00 EDT, a TCP-only experiment will be conducted on the ARPANET. During this period, the ARPANET IMPs will be disabled from sending NCP Host-to-Host traffic, and network traffic measurements will be made. The method that will be used to disable the NCP traffic will be for the IMPs to reject any messages submitted by the hosts that use link 0 (i.e., that have bits 65-72 in the 1822 leader set to zero). If an IMP receives such a message, it will respond to the host with a type 7 (destination host or IMP dead) subtype 3 (communication with the destination host is administratively prohibited) message (see BBN Report 1822, Page 3-30). This response is consistent with the IMP's present behavior, and this is similar to the method that was used when short leaders were removed from the network. During the test, hosts that are running NCP and TCP in parallel with shared remote host state tables may encounter some problems unless their NCP is turned off for the duration. Several TOPS-20 TCP implementations fall into this category, and other hosts may as well. TCP-only hosts should encounter no difficulties, and NCP-only hosts will be unable to use the network. It is important to note that this method of disabling NCP traffic will be used once the network passes the TCP-only date next year (1 Jan 83), so your host software should (if it cannot now) be able to correctly recognize and handle type 7, subtype 3 messages from the IMP. Any technical questions concerning the test may be directed to Andrew Malis (Malis@bbn-unix). Any administrative questions should be directed to DCA Code B645 (formerly Code 252) (DCACODE252USC-ISI). Regards, Jack Snively DCA Code B645(252) ARPANET Managment Telephone: (202) 692-6175/6176 or (AV) 222-6175/6176. -------