Editor's Note: Minutes received 11/20/92 CURRENT_MEETING_REPORT_ Reported by Christian Huitema/INRIA Minutes of the Simple Internet Protocol BOF (SIP) The Simple Internet Protocol BOF attracted a wide audience. The first part of the meeting was a quick review of the proposed SIP Charter, which was approved by the Group modulo alignment of the milestone dates with the proposed IESG decision schedule. The participants were reminded of the name of the mailing list: and that preliminary versions of the documents can be obtained by anonymous ftp from ``parcftp.xerox.com'' in the directories ``pub/sip'' or ``pub/net-research''. Related documents on IPAE can be obtained from the same server in the directory ``pub/ip-encaps''. The discussion turned next to the SIP specifications, addressing a set of characteristic design points, and in particular some issues that were marked as provisional in the current specification: o Steve Deering presented a problem posed by the difference between the TCP pseudo header ``conceptual layout'' and the actual layout of the payload length and type fields in the packets, and asked whether conceptual and physical layout should be aligned. It was observed that the pseudo header remains constant (modulo the packet length) for the duration of the connection, while changing the layout would makes the hop count handling in each packet somewhat slower. Moreover, the relation between packet layout and pseudo header will have to remain ``conceptual'' when options like source routing are used. It was decided not to change the packet layout, but to explain more clearly the pseudo checksum computation rules in the documentation. o Some Group members questioned the absence of a checksum in the network header. This item had already been debated in the mailing list. The arguments for omitting the checksum will have to be presented in detail in a SIP overview document. o Some Group members questioned the small size of the payload type field, and the need to provide an extension mechanism, e.g., for student projects. Various solutions were proposed, e.g., to reserve the value ``255'' for an extension mechanism. The need for a payload type indicating ``intermediate options'' (to be processed by all routers) was mentioned in the same discussion. An example of a request for such options may be the need of performing ``trace route'' on a multipoint address. This mechanism will have to be documented in the specification. o The discussion on ``flow-ids'' showed that there was no consensus on this point that many members feel as deserving further research, and that the corresponding bits should remain reserved in the 1 initial specification. However, the first implementors reported that the presence of a TOS field similar to that of IPv4 would help the transition process. This field will have to be added in the revised specification. One of the results of the discussions of the specifications was to outline the need for an ``overview'' document. The discussion turned then to addressing. Ross Callon objected that the 64 bits SIP addresses were smaller than the 160 bits NSAPs, so could not so easily be used to incorporate link layer addressing, e.g., telephone numbers. The discussion showed that the Working Group did not believe that the NSAP size was justified or needed, and that there is virtue in keeping the addresses compact. Steve Deering presented then the ``metropolitan'' addressing plan. One of the result of the discussion was to outline again the need of more explanations. The overview or the addressing documents should explain how mobility, renumbering and policy routing are supported, based on concrete examples. Attendees Cynthia Bagwell cbagwell@gateway.mitre.org David Bolen db3l@ans.net Ross Callon callon@bigfut.lkg.dec.com Ken Carlberg Carlberg@cseic.saic.com Stephen Casner casner@isi.edu Rob Coltun rcoltun@ni.umd.edu Michael Conn 4387451@mcimail.com Chuck Cranor chuck@maria.wustl.edu David Crocker dcrocker@mordor.stanford.edu Michael Davis mad@spirit.clearpoint.com Steve Deering deering@parc.xerox.com Barbara Denny denny@erg.sri.com Kurt Dobbins dobbins@ctron.com Jon Dreyer Jon.Dreyer@east.sun.com Ralph Droms droms@bucknell.edu Donald Eastlake dee@ranger.enet.dec.com Robert Enger enger@reston.ans.net William Fink bill@wizard.gsfc.nasa.gov Karen Frisa karen.frisa@andrew.cmu.edu Shoji Fukutomi fuku@furukawa.co.jp Robert Gilligan Bob.Gilligan@eng.sun.com Joseph Godsil jgodsil@ncsa.uiuc.edu Masayoshi Gohara mg@sinet.ad.jp Heather Gray heather@zk3.dec.com William Haggerty haggerty@ctron.com Joel Halpern jmh@network.com Robert Hinden hinden@eng.sun.com Don Hoffman don.hoffman@eng.sun.com Christian Huitema christian.huitema@sophia.inria.fr John Ioannidis ji@cs.columbia.edu Ronald Jacoby rj@sgi.com Charley Kline cvk@uiuc.edu 2 Tracy Mallory tracym@3com.com Greg Minshall minshall@wc.novell.com Dave Monachello dave@pluto.dss.com Andy Nicholson droid@cray.com Erik Nordmark nordmark@eng.sun.com Joseph Ramus ramus@nersc.gov Benny Rodrig 4373580@mcimail.com Henry Sanders henrysa@microsoft.com Henning Schulzrinne hgs@research.att.com William Simpson Bill.Simpson@um.cc.umich.edu Frank Solensky solensky@andr.ub.com Tang Tang tt@virginia.edu Richard Thomas rjthomas@bnr.ca Jim Thompson jim@tadpole.com Stuart Vance vance@tgv.com Gregory Vaudreuil gvaudre@cnri.reston.va.us A. Lee Wade wade@nsipo.nasa.gov Chuck Warlick warlick@theophilis.nsfc.nasa.gov Luanne Waul luanne@wwtc.timeplex.com Douglas Williams dougw@ralvmg.vnet.ibm.com Kirk Williams kirk@sbctri.sbc.com Daniel Wilson dvw@bellcore.com Robert Woodburn woody@sparta.com 3