[IMR] IMR84-12.TXT DECEMBER 1984 INTERNET MONTHLY REPORTS ------------------------ The purpose of these reports is to communicate to the Internet Research Group the accomplishments, milestones reached, or problems discovered by the contractors in the ARPA Internet Research Program. This report is for research use only, and is not for public distribution. Each contractor is expected to submit a 1/2 page report on the first business day of the month describing the previous month's activities. These reports should be submitted via ARPANET mail to Westine@USC-ISIF. Reports are requested from BBN, LINKABIT, ISI, LL, MIT-LCS, NTA, SRI, and UCL. Other groups are invited to report newsworthy events or issues. BBN LABORATORIES AND BBN COMMUNICATIONS CORPORATION --------------------------------------------------- TOPS-20 TCP/IP Jil Westcott and Charles Lynn attended a meeting at DEC Marlboro to discuss schedules for including the current BBN TOPS20 Internet code into release 6 of the TOPS20 monitor. Merging the code continues to progress, but was slower than anticipated due to investigation of bug reports (the TCP has been caught exceeding the window) and the problem noted below. Charles Lynn attended a meeting at the DDN PMO to discuss 1 delay problems between SAC/Ft. Bragg/DARPA and ISI and to plan how to determine what is happening in each of component of the internet when an user is in a long delay situation. Continuous monitoring at ISI has been expanded to collect connection data which can be examined after a problem is reported. Hopefully, the resulting ocean of bits will contain clues to the problem or indicate that the wrong data is being collected. GATEWAYS The design of the Butterfly gateway continues to progress. We are now at the stage where we will begin to write some code to try out some of our design ideas. The new Host Monitoring Protocol (HMP) RFC was released. We are working on a revision of the EGP specification to handle "stub" gateways which we expect to release in early January. Plans for the Gateway SIG to be held at ISI the last two days of Feburary are progressing. SATNET The C/30 to replace the Honeywell 316 Satellite IMP at Tanum was shipped to Norway and is currently in Oslo. BBN Field Service will install the machine as soon as it has been shipped from there to Tanum, Sweden. WIDEBAND SATELLITE NETWORK The Wideband Network operated with three sites on the satellite channel throughout most of December. A PSAT software bug, limiting the number of sites on the channel, was uncovered while attempting to bring up the Ft. Monmouth site during December. It is hoped that this problem will be resolved in early January. The ISI site has been operating with a new ESI-A stably since December 7. The old ESI from ISI was refurbished by Linkabit during the month and has been shipped to SRI. SRI is expected to be returned to full operational status during early January. VAX UNIX TCP/IP This month, work progressed on the port of the BBN TCP/IP to 4.2 BSD. The code compiles and link-edits, and we have begun testing. Some of the questions resolved involved the routing algorithms (i.e., whether we should use Berkeley's or retain our own), and the larger question of how much of the interface code between the TCP/IP code and the socket (user interface) to use. 2 Bob Hinden ISI --- INTERNET PROJECT GENERAL: Jon Postel and Joyce Reynolds visited the NIC for discussions on the Domain Plan and to coordinate on a number of protocol administrative matters. Joyce Reynolds gave a seminar on CSNET. DOMAINS: Paul Mockapetris and Ruth Brungardt worked on the domain system implementation. MULTIMEDIA MAIL: Alan Katz worked on implementing ST and IP.ST protocols on the PERQ in order to communicate with the PVT voice terminals for multimedia mail. Joyce Reynolds made preparations for Multimedia Mail exchanges with BBN. TEST TOOLS: Greg Finn worked on the testing of the 1108 Lisp implementation of IP, ICMP, and Address Resolution protocols continues. Discussion with Xerox concerning interface to higher level protocols (TCP) is resulting in some changes. Annette DeSchon has been implementing an Address Resolution Protocol to run in the Mesa Development Environment on the XEROX 8010. David Smallberg found a snag in the implementation of the UDP little servers. FILTER INTERFACE: Paul Mockapetris worked on the TCP measurement code. WIDEBAND PROJECT No internet-related progress to report. COMPUTER CENTER Efforts were made to help isolate problems of slow response between TACs and Tops-20s which had been observed on ISI systems. A meeting was held at DDN/PMO with representitives from BBN, ISI, DDN, and SAC to develop plans for increased monitoring in the TAC, IMP, and TOPS-20 that could be activated during periods of poor response. Tentative plans for an uncontrolled message experiment were also made. In cooperation with Peter Ditmars, two tests were run between ISIE and SAC-TAC. Tops-20 trace information was collected and given to Peter. In cooperation with Charles Lynn, the Tops-20 network 3 monitoring code was expanded, and a bug was found and fixed that had been preventing monitoring datagrams from being sent in reply to probes. Directories were set up on ISIA and ISIE to hold collected data. Work to fit further additions to the monitoring code into ISI Tops-20 is near completion. Joel Goldberger LINCOLN LAB ----------- A command has been added to the IP/ST gateway control and monitoring capability that allows an ICMP echo request probe to be sent to an arbitrary internet address. The probe may be source-routed by typing additional IP addresses up to the limit posed by the size of the option field in the IP header. When the echo response is returned, a line is typed on the monitor screen. Broadcast or group addresses may be used to get multiple responses from sets of hosts or gateways. (Interesting flurries of activity can be caused by such addresses within the source route.) The IP/ST gateways now send the current date and time across the WB SATNET in the "please join my group" messages that they send to each other. When a gateway receives such a message it checks to see if its operating system had been brought up without anyone entering the date and time. If such had been the case, the gateway program will set the operating system time as well as its own concept of time that it uses for logging events of interest. Time setting is the latest of a series of features that have been added to speed up and simplify the process of bringing up the IP/ST gateways in the field. Pushing the boot switch on the front panel of the PDP 11/44 is now all that is needed to bring up a gateway. During the past several months Steve Casner of ISI has made a number of changes to the EPOS operating system to support this capability and to provide us with full access to virtual memory in the 11/44. We are grateful for his efforts. Jim Forgie LINKABIT -------- 1. We packed up the fuzzballs for the move to new offices in Vienna, Virginia. Our local-net zoo will be isolated pending 4 reconnection of our ARPANET access line, expected before 19 January. 2. With Jon's kind help, RFC889, a summary of my Internet delay experiments reported last month, RFC891, a specification of the protocols mumbled in our local-net zoo, and RFC892, a copy of the ISO Transport Protoocl Specification, were distributed. 3. Our TCP experiments continued with the rebuilding of the buffering and packetization algorithms. The result of this was a worthwhile increase in efficiency along with a reduction in buffering requirments. The retransmission algorithm was further refined to improve its behavior in cases of large delay means and variances. Extensive tests with the new trace/trap facilities over several ornery paths including SATNET showed the changes are working well. 4. The TCP testing program continued to catch bugs previously obscured by performance shortfalls. The TOPS-20 "runaway ACK" bug continues to cause severe bleeding in our ARPANET gateway and presumably others as well. At least one host on the ARPANET continues to send jumbograms larger than 576 octets without prior agreement, leading to busted 1822 packets. A raunchy bug was discovered in which the TOPS-20 TCP sender overran the reciever window, improperly repacketize the retransmission and finally broke the connection. The client (SMTP) then tried to re-send using 50-octet segments. Sound familiar? 5. While cleaning up some old timekeeping business, I discovered the local power grid is even less stable than I thought. relative time slips exceeding 8 milliseconds per second were observed over the Christmas break, well in excess of anything measured before. I retuned the time- synchronization parameters again to allow for these excursions. We bought one of the new Heath WWV-synchronized radio clocks, which are relatively inexpensive. Initial tests show that these clocks can show errors up to a large part of a second. 6. Our EGP gateway continues to track the routing information from the BBN test gateway; however, on a number of occasions the BBN test gateway itself apparently became isolated so that we lost connectivity. Our new packet-trace/trap facility found an alarming incidence of misrouted ARPANET packets and resulting gushers of redirects. These spasms, almost certainly due to flapping gateways and nets somewhere in the ooze, often persisted up to two minutes and on some occasions to twenty minutes. With so many GGP gateways now on the ARPANET, spasms 5 of this magnitude must be expected; however, the cost has become very serious. Dave Mills MIT-LCS ------- C Gateway Management of exterior net routing information in MIT's internal gateways is being changed to maintain a cache of exterior nets with the best next hop to the net. The immediate motivation for this change is that we need to reach a B address net via an internal MIT gateway; currently all packets destined to B net addresses are sent to one MIT gateway which connects MIT with the ARPANET. For the moment the cache will be managed statically. When MIT's interior gateway protocol is designed, it will be used to initialize and update each internal gateway's cache of routes to exterior nets. This protocol will also be used to dynamically maintain all MIT gateways' subnet routing tables. The software has been designed to allow easy configuration of gateways to use 1) static routing, 2) interior gateway protocol, or 3) exterior and interior gateway protocols. Design and implementation of the software are almost complete; debugging should start soon. This month we noticed that 576 byte internet packets were not getting from hosts on the ARPANET to hosts on our 10Mbit ethernet. It turned out that three of our gateway configurations were not handling 576 byte packets properly. The ARPANET to PRONET gateway zeroed out the last byte of data in a 576 byte packet; this appeared to happen somewhere in the arpanet serial line input code. We added four trailer bytes to the ARPANET device specification (so that reads from the ARPANET could handle extra trailer/pad bytes) and the problem went away. The Bridge Communications gateway had a different problem. It was forwarding the entire packet, encapsulated in the header and trailer received from the 10Mbit ethernet, out onto the PRONET. One host was transmitting two extra bytes onto the ethernet with its internet packets which caused 576 byte internet packets to become 578 byte packets (plus PRONET header) when forwarded onto the PRONET. The PRONET drivers are not prepared to receive such large packets and discarded them. The Bridge Communications gateway was changed to only forward the contents of the internet packet between nets. The third configuation, whose 576 byte packet forwarding problem we are still studying, is the LSI 11/03 10Mbit to PRONET gateway. We notice that the last four bytes of data in a 576 6 byte internet packet are trashed on input from the 10Mbit ethernet. In late November we created, for the first time, a configuration of the CGW that contains both a 10MB and a 3MB Ethernet interface. After fixing a few name conflicts, the configuration was released to Stanford where it ran without any problems. The Stanford gateway, Golden Gate, now contains three network interfaces and it still has room for 17 packet buffers. Support for EGP is not included in the Golden Gate configuration. IBM Personal Computer Since MS-DOS (the PC's operating system) does not support multiple processes running concurrently, the user telnet was modified to include server TFTP. This provides a more convenient way to transfer many files to the PC. The TFTP server may be turned on or off; the telnet user is notified whenever a TFTP request is received and is asked to verify the request before it is accepted. This telnet/TFTP scheme is uncovering some naming problems. Most PCs on the net do not have their names listed with the various name servers so some form of numeric address must be used to specify which PC a file should be tranferred to. But there is no common numeric address format across machines, some do not even accept numeric host names, so the user is left with annoying naming inconsistencies. The timeout strategy in TFTP was improved and the program now works well with a range of networks, from a 300 baud serial line to a 10Mb ethernet. It formerly would almost always timeout on a 1200 baud line. A number of bugs were corrected in the area of timers, as well. A user TCP/Supdup was brought up on the PC; this program also has a built-in TFTP. Unfortunately, there are only a few machines on the net which run server Supdup. The ethernet driver was modified to allow the interrupt vector location it uses to be modified by individual users after the program has been loaded. This change means that the ethernet driver can run on an XT; the hard disk controller on an XT uses the interrupt vector location the ethernet driver had been using. Several bugs in the way the ethernet driver decided whether a packet was valid were corrected, and a change was made to the Address Resolution Protocol implementation so that Internet address - ethernet address binding may be changed dynamically. 7 Liza Martin NTA --- No report received. SRI --- 1. Development of the Robustness II software is continuing. The conversion of existing utilities to the new prom format should be completed soon. In addition, a new file manager utility is under development. Utilities for floppy disk and bubble copy operations were updated. 2. Development of the virtual memory enhancements to the MOS operating system is proceeding. A technical note covering the various technical options and approaches has been drafted and is being circulated internally for review. 3. Three papers covering the naming, addressing, routing and component cooperation aspects of the problems in accommodating internetwork dynamics have been written and are undergoing internal review. Jim Mathis SRI-NIC ------- No report received. UCL --- 1. Connectivity via Satnet has been quite reasonable this month. The VAN path continues to have reliability problems with quite a number of calls being refused. 2. Some simple measurments done by Robert Cole using the VAN path indicated a maximum throughput of about 1100 bps and an average UK/US delay of about 0.85 second. Peter Lloyd 8 -------