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  1.  
  2. CURRENT_MEETING_REPORT_
  3.  
  4.  
  5. Reported by Dave Crocker/TBO
  6.  
  7. Minutes of the IP Address Encapsulation Working Group (IPAE)
  8.  
  9. IPAE seeks to facilitate Internet conversion to a replacement for the
  10. current Internet Protocol (IPv4) by attending to transition ease of the
  11. installed base.  The primary impetus for replacement of IPv4 is its
  12. limited address space, containing too few bits and having too little
  13. structure for very large-scale global routing tables.  IPAE's technical
  14. approach is to encapsulate the new addressing information inside old
  15. IPv4 headers, so that the new information can transit unmodified
  16. networks.
  17.  
  18. After the Boston (24th) IETF meeting, the IPAE Working Group held a
  19. series of face-to-face meetings in Mountain View, California and usually
  20. with video conference hookups to Cambridge, Massachusetts.  Telephone
  21. conferencing bridges also were available.  EMail activity during this
  22. time was relatively limited.
  23.  
  24. During the time of these interim meetings, Steve Deering, who also had
  25. been participating in IPAE meetings, developed a preliminary
  26. specification for a Simplified IP (SIP) which streamlined the classic IP
  27. header, including addresses of 64 bits.  Over the course of the interim
  28. meetings, IPAE then repositioned itself to focus exclusively on the
  29. question of transition from IPv4 to the new IP, with detailed
  30. specification of the transition focusing on use of SIP as the final
  31. stage of deployment.
  32.  
  33. Working documents of the Working Group are maintained in the at host
  34. `parcftp.xerox.com', in directory `ip-encaps'.  Prior to the Washington
  35. IETF meeting, the IPAE specification was updated in the internet-drafts
  36. directory of the Internet Repository.  Its filename is
  37. `draft-crocker-ip-encaps-01.txt'.
  38.  
  39. November 19th
  40.  
  41. The IPAE session divided into a small amount of review about IPAE, some
  42. discussion of a few open technical issues, and then an extended
  43. presentation about implementation experience, by Erik Nordmark of Sun
  44. and Ron Jacoby of SGI. The Sun implementation is a full IPAE/SIP set of
  45. functionality, at the internet layer, and has been tested with SIP-SIP,
  46. SIP/IPAE-IPAE/SIP, and SIP-IP interactions.  A copy of Nordmark's
  47. presentation is attached.
  48.  
  49. Noteworthy comments about his technical work, on a Unix System V streams
  50. base:
  51.  
  52.  
  53.    o Converting to 64-bit address was somewhat tricky.  (Author note:
  54.      Comments from an earlier effort with BSD code suggests that the
  55.  
  56.                                    1
  57.  
  58.  
  59.  
  60.  
  61.  
  62.      effort was not trivial, but also was not too difficult, though
  63.      addresses larger than 96 bits may pose a problem.)
  64.  
  65.    o Adding re-assembly code was easy, since it is identical to IPv4's
  66.      reassembly.  It took about a half a day's effort.
  67.  
  68.    o Initial throughput testing (on prototype code) showed performance
  69.      about the same as for IPv4.  It must be stressed that the testing
  70.      was by no means thorough, nor was the code tuned.
  71.  
  72.  
  73. Open technical issues for IPAE include Domain Name System, network
  74. management and routing enhancements.  DNS changes appear to be generic
  75. for any addressing upgrade, as do the general requirements for changes
  76. to MIB variables, and use of a routing protocol.  That is, conversion to
  77. larger addresses carries a requirement for a substantial set of changes
  78. to Internet components.  IPAE (and SIP) appear to impose no special
  79. concerns for this.
  80.  
  81. SIP uses addresses which have an IP address in the lower 32-bits.  There
  82. was a suggestion that sites add a DNS entry which contains the UPPER
  83. 32-bits, so that hosts would have easy access to that information via
  84. the DNS. (Author's note:  This presumes a direct relationship between IP
  85. network addresses and DNS domains, which is not required by the DNS
  86. technology.)
  87.  
  88. In questions from the audience, there was some tension between
  89. facilitating transition, versus ensuring a high-quality end-point.
  90. There also was a question of the Group that would have to absorb the
  91. pain of a transition, with the choice being end-users, versus system
  92. operators.  (Author's note:  The term ``end-user'' is ambiguous, since
  93. local-net administrators are end-users, relative to larger service
  94. providers.  Hence, there is a range of targets for absorbing transition
  95. pain.)
  96.  
  97. Vint Cerf observed that users aren't interested in the question; they
  98. simply should not be the ones to do the absorbing.
  99.  
  100.  
  101.  
  102.                                    2
  103.  
  104. ^L 
  105.                                 ===============
  106.                                 | 1.          |  
  107.         Internet                | Packet from |
  108.         layer:                  | transport   |
  109.         Transmit side           |             |  
  110.                                 ===============
  111.                                        |
  112.                                        v
  113.                                 ---------------
  114.                                 | 2.          |  
  115.                                 | Lookup SIP  |
  116.                                 | destination |
  117.                                 |             |  
  118.                                 ---------------
  119.                                        |
  120.                                        v
  121.                                 ---------------
  122.                                 | 3.          |  
  123.                                 | Finish SIP  |
  124.                                 | header (src |
  125.                                 | address)    |
  126.                                 |             |  
  127.                                 ---------------
  128.                                        |<------------------- From 21
  129.                ------------------------?----------------
  130.                |               |                       | 
  131.          Dest is the    C-bit(dest) and         Other destination
  132.          local host.    in this site.                  | 
  133.                |               |                       | 
  134.                v               v                       v 
  135.         =============== ---------------         ---------------
  136.         | 4.          | | 5.          |         | 6.          |  
  137.         | Deliver to  | | Convert SIP |         | SIP frag-   |
  138.         | transport   | | to IP       |         | mentation   |
  139.         |             | |             |         | (if needed) |
  140.         =============== ---------------         |             |  
  141.                                |                ---------------
  142.                                v                       | 
  143.                         ---------------        --------?--------
  144.                         | 7.          |        |               | 
  145.                         | IP header   | C-bit(next_hop)  Other next_hop
  146.                         | checksum    |        |               | 
  147.                         |             |        v               | 
  148.                         --------------- ---------------        | 
  149.                                |        | 9.          |        | 
  150.                                v        | Encapsulate |        | 
  151.                         --------------- | in IP hdr   |        | 
  152.         From 15 ------->| 8.          | |             |        | 
  153.                         | IP frag-    | ---------------        | 
  154.                         | mentation   |        |               | 
  155.                         | (if needed) |        |               | 
  156.                         ---------------        |               | 
  157.                                |               |               | 
  158.                                ---------------------------------
  159.                                                |
  160.                                                v
  161.                                         ===============
  162.                                         | 10.         |  
  163.                                         | Transmit    |
  164.                                         | (incl ARP)  |
  165.                                         |             |  
  166.                                         ===============
  167. ^L
  168.         Internet                                          Goto after 3
  169.         layer:                                                 ^
  170.         Receive side                                           |
  171.         ===============         ---------------         ---------------
  172.         | 22.         |         | 20.         |         | 21.         |  
  173.         | Deliver to  |<--------| SIP reas-   |         | Decrement   |
  174.         | transport   |         | sembly.     |         | SIP hopcount|
  175.         |             |         |             |         |             |  
  176.         ===============         ---------------         ---------------
  177.                                        ^                       ^ 
  178.                                   This host               Other destination
  179.                                        |                       | 
  180.                                        ----------------?--------
  181.                                                        |
  182.                                                 ---------------
  183.                -------------------------------->| 19.         |  
  184.                |                                | Lookup SIP  |
  185.         --------------- ===============         | destination |
  186.         | 17.         | | 18.         |         |             |  
  187.         | Strip IP    | | Deliver to  |         ---------------
  188.         | header      | | transport   |                ^ 
  189.         |             | |             |                | 
  190.         --------------- ===============                | 
  191.                ^               ^                       | 
  192.         Protocol == IPAE   Other protocol              | 
  193.                |               |                       | 
  194.                ?----------------                       | 
  195.                |                                       | 
  196.                |            Goto 8             -----------------
  197.                |               ^               |               | 
  198.         --------------- --------------- ---------------        | 
  199.         | 14.         | | 15.         | | 16.         |        | 
  200.         | IP reas-    | | Decr. ttl   | | Convert IP  |        | 
  201.         | sembly.     | | Update cksum| | to SIP.     |        | 
  202.         |             | |             | |             |        | 
  203.         --------------- --------------- ---------------        | 
  204.                ^               ^               ^               | 
  205.           This host        This site      Other site           | 
  206.                |               |               |               | 
  207.                --------?------------------------               | 
  208.                        |                                       | 
  209.                 ---------------                                | 
  210.                 | 13.         |                                | 
  211.                 | Lookup IP   |                                | 
  212.                 | destination |                                | 
  213.                 |             |                                | 
  214.                 ---------------                                | 
  215.                        ^                                       | 
  216.                 ---------------                                | 
  217.                 | 12.         |                                | 
  218.                 | Verify IP   |                                | 
  219.                 | hdr checksum|                                | 
  220.                 |             |                                | 
  221.                 ---------------                                | 
  222.                        ^                                       | 
  223.                    IPv4 packet                            SIP packet
  224.                        ----------------?------------------------
  225.                                        ^
  226.                                        |
  227.                                 ===============
  228.                                 | 11.         |  
  229.                                 | Receive from|
  230.                                 | link layer  |
  231.                                 |             |  
  232.                                 ===============
  233.  
  234.