From: CSBVAX::MRGATE!RELAY-INFO-VAX@CRVAX.SRI.COM@SMTP 21-SEP-1988 04:17 To: ARISIA::EVERHART Subj: VMS 5.0 Level-2 Routers-Forked tongue!! Received: From KL.SRI.COM by CRVAX.SRI.COM with TCP; Tue, 20 SEP 88 16:03:30 PDT Received: from stc10.ctd.ornl.gov by KL.SRI.COM with TCP; Tue, 20 Sep 88 15:32:45 PDT Date: 20 Sep 88 08:37:00 EST From: "PHYVAX::BEMIS" Subject: VMS 5.0 Level-2 Routers-Forked tongue!! To: "info-vax" VMS Level-2 Routers Under VMS 5. (DECnet Phase IVa) Speak with Forked Tongue C. E. Bemis, Jr. , September 7, 1988 *************************************************** I have had the opportunity to observe a Level-2 VAX VMS node under VMS Version 5.0. With this VMS release, the DECnet stuff has changed and we have DECnet Phase IVa (or IV+) under VMS version 5. The Level-2 (AREA) Routers do all the normal stuff that happened under DECnet Phase IV, ie. Multicast L-2 stuff to AB-00-00-03-00-00, AND, they also Multicast to 09-00-2B-02-00-00 !!. By default, and perhaps beyond human control, all L-2's Multicast to 09-00-2B-02-00-00, once every 15 seconds (a sample packet is given below). Now, what is this NEW Multicast, spoken by all Level-2 VMS DECnet Routers under Phase IVa?? Looking in my DECnet Phase V architecture book (EK-DNAPV-GD) on page 31, I find the answer-- "For example, the Network layer on DNA Level-2 routers receives frames addressed the multicast address 09-00-2B-02-00-00". So--What is this new stuff doing under Phase-IVa ?? For help, I turn to the ISO-IP document, ANSI X3S3.3/87-150R. Looking on page 70, section 7.4.2, I learn about LAN Router Hello's. I learn about Router Hello PDU's, and their structure, on page 76 and find out what is in the L-2 to L-2 Multicast, ie. the Multicast to "ALL-L2-ROUTERS". The packets do not conform, BUT INSTEAD, they are the usual Phase-IV L2 to L2 Multicast with just a list of all the L2's on the Broadcasting LAN (same as the L2 to L2 stuff Multicast to AB-00-00-03-00-00). For example, in Packet 99 below, I see the following L2's that node 52.001 knows about: AA-00-04-00-F4-A9 42.500 AA-00-04-00-28-D0 52.040 AA-00-04-00-35-CC 51.053 AA-00-04-00-01-D4 53.001 etc.--standard Phase IV L2 stuff QUESTIONS**** 1. Why do Broadcasting LAN's under Phase-IV have to bear this additional Multicast burden when it does not do anybody any good ??? Just more stuff cluttering the entire Broadcasting net. Tis clear that the "brain damaged" RSX DECSA's will never do anything with it, never mind speak it to give you an example of use-less-ness. 2. Did DEC screw up and let this little thing out of the bag before its time??? Did someone forget to turn off this Multicast in the release of DECnet Phase IVa??? Is a description of this little nasty documented anywhere?? 3. To be fair to DEC, I can see its value in Phase-V DECnet--For example, we have a way to split the Routing stuff, ie. the differences between L1 and L2. Thus, in Phase-V, the L1 AB-00-00-03-00-00 Multicasts could be blocked behind a LAN-100 bridge keeping the rest of the extended network quiet. Only the L2 09-00's would be sent everwhere on the broadcasting net. BUT, why in Phase-IVa?? *************** Here is a sample of the 09-00-2B-02-00-00 packets Multicast by the Level-2 VMS Version 5.0 node DSAREA, 52.001. As mentioned before, this NEW Multicast, sent every 15 seconds, is the L2 to L2 Router Hello as defined for a Broadcasting subnet for DECnet Phase V Level-2's. Details of this stuff are in the ISO-IP document as defined by the ANSI subcommittee X3S3.3 for "Intermediate systems (IS) to Intermediate Systems (IS) Intra Domain Routing Exchange Protocol". This is the ISO-IP standard, to which DECnet Phase-V will "CONFORM" to (note- I said CONFORM not Comply !!) Packet 99, received 7-SEP-1988 13:26:37.54 Length: 92 bytes Protocol: 6003 (DEC_NET) Source: AA-00-04-00-01-D0 Dest: 09-00-2B-02-00-00 4005DA01 D0010004 00AA0000 020B005A "Z.....*....P.Z.@" 0000 0400AA3F 00000000 00000047 0F000F00 "....G.......?*.." 0010 14000400 AACBD401 000400AA DACCE800 ".hLZ*....TK*...." 0020 B2A9F400 0400AAC0 D0280004 00AAC0D8 "X@*...(P@*...t)2" 0030 00AAC6CC 35000400 AAC0DC32 000400AA "*...2\@*...5LF*." 0040 00000000 D5CCE700 0400AAC0 D8190004 "...X@*...gLU...." 0050 ******************* Here is a sample of the NORMAL Level-2 Router Hellos, ie. the usual Multicasts to AB-00-00-03-00-00 that were always there in DECnet Phase IV. This is spoken every 16 seconds --As you see, they are the same as the Multicasts to 09-00-2B-02-00-00. Packet 130, received 7-SEP-1988 13:26:38.55 Length: 92 bytes Protocol: 6003 (DEC_NET) Source: AA-00-04-00-01-D0 Dest: AB-00-00-03-00-00 4005DA01 D0010004 00AA0000 020B005A "Z.....*....P.Z.@" 0000 0400AA3F 00000000 00000047 0F000F00 "....G.......?*.." 0010 14000400 AACBD401 000400AA DACCE800 ".hLZ*....TK*...." 0020 B2A9F400 0400AAC0 D0280004 00AAC0D8 "X@*...(P@*...t)2" 0030 00AAC6CC 35000400 AAC0DC32 000400AA "*...2\@*...5LF*." 0040 00000000 D5CCE700 0400AAC0 D8190004 "...X@*...gLU...." 0050 ******************* This is a sample packet, also sent to AB-00-00-03-00-00, BUT, this one is the Level-1 Routing Multicast. This node also does the L1 stuff once every 10 seconds. Packet 211, received 7-SEP-1988 13:26:41.45 Length: 76 bytes Protocol: 6003 (DEC_NET) Source: AA-00-04-00-01-D0 Dest: AB-00-00-03-00-00 04040000 00000000 002000D0 0107004A "J...P. ........." 0000 04040404 04047FFF 7FFF7FFF 04047FFF "................" 0010 04047FFF 7FFF0404 04040404 7FFF7FFF "................" 0020 7FFF0404 04040404 7FFF0404 7FFF7FFF "................" 0030 00000000 BC557FFF 04040404 7FFF7FFF "..........U<...." 0040 Curt(is) E. Bemis, Jr. ************************************************************************* local(ORNL) to: PHYVAX::BEMIS (or STC::CBB) BITNET to: cbb@ORNLSTC DDN(ARPA) to: cbb@stc10.ctd.ornl.gov -OR- bemis%phyvax.decnet@stc10.ctd.ornl.gov HEPnet to: ORPH01::BEMIS -OR- 42.501::BEMIS -OR- 43509::BEMIS USnail:Physics Div.,Bldg.6000,MS-371,P.O.Box 2008,ORNL,Oak Ridge,TN 37831 Voice: (615) 574-4769 -OR- FTS 624-4769 **************************************************************************