CURRENT_MEETING_REPORT_ Reported by Richard Fox/Synoptics FDDI Minutes The meeting was solely comprised of a presentation by Caralyn Brown and Doug Bagnall called, ``ARP extensions for Dual Mac Stations''. Currently ARP supports a 1-1 mapping of IP addresses to MAC addresses. FDDI supports the notion of 1-2 mapping of IP addresses to MAC addresses. Our goal is not to have a TCP connection break when a wrap happens. To meet this objective it was suggested that an extension to the current ARP protocol is needed, where the new ARP protocol supplies more than a 1-1 mapping but a 1-many mapping. An example of this is: ARP response= One step identified in achieving this is to add a new SNAP value. At this point 2 approaches were presented and compared. Solution 1: Hybrid approach Have a parameter that says that no backward compatibility is to be maintained. Thus, send old style ARP but encode stuff in target fields. Advantages: only need to send 1 ARP for all cases. Disadvantages: encoding may break some implementations and this solution doesn't scale very well. Some people said that this method is better solved at layer 3; reply to this was to rewrite layer 3; thus this solution is less radical than rewriting layer 3. Solution 2: Extended ARP This solution requires that a new ARP packet be sent out each interface (this packet is called an EARP and is slightly different than the normal ARP packet). After an EARP is sent the station must set a timer and wait for a response. If no response is received then the station must assume that the receiver of the ARP doesn't understand EARPs and so it must send out a normal ARP. Advantages: backwards compatibility. Disadvantages: may need to send out 2 ARP requests before an answer is received. 1 Other issues that came up with this solution are: o When ring wraps/unwraps stations should send ARP to itself to update everybody's ARP table -- do this only after a settling period. Some people felt that the SRF frame takes care of this, others not convinced, no resolution. At this time we listed advantages of allowing stations to have 2 macs. The 3 identified reasons are: - Load balancing (transparent). - Transparent error recovery. - Dual mac in wrap: you don't know where response came from. o Need EARP since non-wrapped stations can use wrong ring when a station is wrapped. EARPs keeps effect to wrapped stations only.(??) At this point we got into varied discussions on how wrapped rings and IP do not get along. Some people want to force all single MAC stations to be connected to the primary ring only (or at least on the same ring), others feels that this rule breaks the concept of FDDI. o It was suggested that we continue to use RFC 1122 for ARP cache handling. Attendees Douglas Bagnall bagnall_d@apollo.hp.com Alison Brown alison@maverick@osc.edu Caralyn Brown cbrown@ENR.Prime.com Cho Chang chang_c@apollo.hp.com Andrew Cherenson arc@sgi.com Cyrus Chow cchow@orion.arc.nasa.go Paul Ciarfella ciarfella@levers.enet.dec.com Nadya El-Afandi nadya@network.com Richard Fox sytek!rfox@sun.com Michael Grobe grobe@kuhub.cc.ukans.edu Susan Hares skh@merit.edu Peter Hayden hayden@levers.enet.dec.com Ajay Kachrani kachrani%regent.dec@decwrl.dec.com Jay Kadambi jayk@iwlcs.att.com John LoVerso loverso@xylogics.com Rebecca Nitzan nitzan@nsipo.nasa.gov James Reeves jreeves@synoptics.com Bill Townsend townsend@xylogics.com Bert Williams bert.synernetics@mailgate.synnet.com Linda Winkler b32357@anlvm.ctd.anl.gov Sijiam Zhang szhang@cs.ubc.ca 2