CURRENT_MEETING_REPORT_ Reported by Dave Crocker/TBO Minutes of the IP Address Encapsulation Working Group (IPAE) IPAE seeks to facilitate Internet conversion to a replacement for the current Internet Protocol (IPv4) by attending to transition ease of the installed base. The primary impetus for replacement of IPv4 is its limited address space, containing too few bits and having too little structure for very large-scale global routing tables. IPAE's technical approach is to encapsulate the new addressing information inside old IPv4 headers, so that the new information can transit unmodified networks. After the Boston (24th) IETF meeting, the IPAE Working Group held a series of face-to-face meetings in Mountain View, California and usually with video conference hookups to Cambridge, Massachusetts. Telephone conferencing bridges also were available. EMail activity during this time was relatively limited. During the time of these interim meetings, Steve Deering, who also had been participating in IPAE meetings, developed a preliminary specification for a Simplified IP (SIP) which streamlined the classic IP header, including addresses of 64 bits. Over the course of the interim meetings, IPAE then repositioned itself to focus exclusively on the question of transition from IPv4 to the new IP, with detailed specification of the transition focusing on use of SIP as the final stage of deployment. Working documents of the Working Group are maintained in the at host `parcftp.xerox.com', in directory `ip-encaps'. Prior to the Washington IETF meeting, the IPAE specification was updated in the internet-drafts directory of the Internet Repository. Its filename is `draft-crocker-ip-encaps-01.txt'. November 19th The IPAE session divided into a small amount of review about IPAE, some discussion of a few open technical issues, and then an extended presentation about implementation experience, by Erik Nordmark of Sun and Ron Jacoby of SGI. The Sun implementation is a full IPAE/SIP set of functionality, at the internet layer, and has been tested with SIP-SIP, SIP/IPAE-IPAE/SIP, and SIP-IP interactions. A copy of Nordmark's presentation is attached. Noteworthy comments about his technical work, on a Unix System V streams base: o Converting to 64-bit address was somewhat tricky. (Author note: Comments from an earlier effort with BSD code suggests that the 1 effort was not trivial, but also was not too difficult, though addresses larger than 96 bits may pose a problem.) o Adding re-assembly code was easy, since it is identical to IPv4's reassembly. It took about a half a day's effort. o Initial throughput testing (on prototype code) showed performance about the same as for IPv4. It must be stressed that the testing was by no means thorough, nor was the code tuned. Open technical issues for IPAE include Domain Name System, network management and routing enhancements. DNS changes appear to be generic for any addressing upgrade, as do the general requirements for changes to MIB variables, and use of a routing protocol. That is, conversion to larger addresses carries a requirement for a substantial set of changes to Internet components. IPAE (and SIP) appear to impose no special concerns for this. SIP uses addresses which have an IP address in the lower 32-bits. There was a suggestion that sites add a DNS entry which contains the UPPER 32-bits, so that hosts would have easy access to that information via the DNS. (Author's note: This presumes a direct relationship between IP network addresses and DNS domains, which is not required by the DNS technology.) In questions from the audience, there was some tension between facilitating transition, versus ensuring a high-quality end-point. There also was a question of the Group that would have to absorb the pain of a transition, with the choice being end-users, versus system operators. (Author's note: The term ``end-user'' is ambiguous, since local-net administrators are end-users, relative to larger service providers. Hence, there is a range of targets for absorbing transition pain.) Vint Cerf observed that users aren't interested in the question; they simply should not be the ones to do the absorbing. 2 ^L =============== | 1. | Internet | Packet from | layer: | transport | Transmit side | | =============== | v --------------- | 2. | | Lookup SIP | | destination | | | --------------- | v --------------- | 3. | | Finish SIP | | header (src | | address) | | | --------------- |<------------------- From 21 ------------------------?---------------- | | | Dest is the C-bit(dest) and Other destination local host. in this site. | | | | v v v =============== --------------- --------------- | 4. | | 5. | | 6. | | Deliver to | | Convert SIP | | SIP frag- | | transport | | to IP | | mentation | | | | | | (if needed) | =============== --------------- | | | --------------- v | --------------- --------?-------- | 7. | | | | IP header | C-bit(next_hop) Other next_hop | checksum | | | | | v | --------------- --------------- | | | 9. | | v | Encapsulate | | --------------- | in IP hdr | | From 15 ------->| 8. | | | | | IP frag- | --------------- | | mentation | | | | (if needed) | | | --------------- | | | | | --------------------------------- | v =============== | 10. | | Transmit | | (incl ARP) | | | =============== ^L Internet Goto after 3 layer: ^ Receive side | =============== --------------- --------------- | 22. | | 20. | | 21. | | Deliver to |<--------| SIP reas- | | Decrement | | transport | | sembly. | | SIP hopcount| | | | | | | =============== --------------- --------------- ^ ^ This host Other destination | | ----------------?-------- | --------------- -------------------------------->| 19. | | | Lookup SIP | --------------- =============== | destination | | 17. | | 18. | | | | Strip IP | | Deliver to | --------------- | header | | transport | ^ | | | | | --------------- =============== | ^ ^ | Protocol == IPAE Other protocol | | | | ?---------------- | | | | Goto 8 ----------------- | ^ | | --------------- --------------- --------------- | | 14. | | 15. | | 16. | | | IP reas- | | Decr. ttl | | Convert IP | | | sembly. | | Update cksum| | to SIP. | | | | | | | | | --------------- --------------- --------------- | ^ ^ ^ | This host This site Other site | | | | | --------?------------------------ | | | --------------- | | 13. | | | Lookup IP | | | destination | | | | | --------------- | ^ | --------------- | | 12. | | | Verify IP | | | hdr checksum| | | | | --------------- | ^ | IPv4 packet SIP packet ----------------?------------------------ ^ | =============== | 11. | | Receive from| | link layer | | | ===============