Re: Last Call: IP Version 6 Addressing Architecture to Proposed Standard
Authors Robert Blokzijl RIPE Chair Daniel Karrenberg RIPE NCC General Manager Background RIPE is an organisation founded in 1989 wich aims to ensure the technical and administrative coordination necessary for the operation of the Internet in Europe [ripe-01]. The RIPE NCC performs activities for the benefit of the Internet service providers (ISPs) in Europe and the surrounding areas; primarily activities that the ISPs need to organise as a group, although they may be competing with each other in other areas. In particular the RIPE NCC, as Regional Internet Registry, allocates and assigns IPv4 address space in Europe and surrounding areas [ripe-162]. The RIPE NCC started operations in 1992. It currently allocates address space to more than 800 local Internet Registries almost all of which are operated by ISPs. The number of local IRs is expected to reach 1250 in 1998. There are currently no indications that the number of local IRs will stop growing. The authors have contributed significantly to the development of the distributed Internet registry system which is used for the allocation and assignment of provider based IPv4 address space today. As such they have ample experience with the development of address space allocation and assignment policies. One important element of current policies is that the size of address space allocations is determined by previous justified use of address space. A prerequisite for this policy is that the size of allocations can start small and increase or decrease according to previous justified usage [ripe-159]. Argument We believe <draft-ietf-ipngwg-unicast-aggr-02.txt> is critically flawed because it standardises address aggregation boundaries without any explicit technical justification. In particular the length of the TLA and NLA fields are proposed to be standardised as fixed at prarticular values with no technical justification for either the fact that these lengths need to be fixed nor for the particular values chosen. The lack of technical justification is significant because the standardisation of TLA and NLA lengths directly influences many elements of Internet operations including address space allocation policies. In particular the TLA being fixed at 13bit length makes only 8K TLAs available per FP. Consequently Internet Registries will not be able to use proven allocation policies but rather engage in regulatory practises. The rules proposed in <draft-ietf-ipngwg-tla-assignment-01.txt> are clear evidence of this. Broad acceptance of such rules and their implementation is extremely unlikely unless there is convincing technical reasoning behind the constraints that necessitate the rules. Because of this critical flaw we request that the IESG not advance <draft-ietf-ipngwg-unicast-aggr-02.txt> and <draft-ietf-ipngwg-addr-arch-v2-05.txt> to proposed standard yet. We suggest that the IESG refer these documents back to the authors and the WG with the request to provide technical justification for the placement of aggregation boundaries and to consider making these boundaries variable where technically feasible. References The referenced RIPE documents can be accessed at http://www.ripe.net/docs/ripe-xxx.html HTML ftp://ftp.ripe.net/ripe/docs/ripe-xxx.txt ASCII ftp://ftp.ripe.net/ripe/docs/ripe-xxx.ps PostScript
Daniel, Have you or someone from RIPE participated on the IPng mailing list? Have you or someone from RIPE participated in the IPng WG meetings at the last three IETF meetings? The reason I ask is because we have done technical analysis on this and have had much discussion. I think discussing the reason for going with a 13bit TLA needs to be brought out more and doing and checking that is prudent. But the architecture and reasoning has had many technical discussions. I would like to understand as a WG member if you or RIPE did not agree with the results (which I would think we would have heard before now) or if you or RIPE have not been part of these open public discussions. It could be we need to point to the mail archives and the GSE reasoning paper done by Thomas Narten, Lixia Zhang, et al from whence this essential proposal came from based on a WG meeting in Mountain View about a year ago? I am trying to understand if this is an educational effort on our part as a WG group? thanks /jim
Quick answer:
bound@zk3.dec.com writes: Daniel,
Have you or someone from RIPE participated on the IPng mailing list?
Have you or someone from RIPE participated in the IPng WG meetings at the last three IETF meetings?
Yes we have. I personally have not been in Memphis, hoever none of us was able to be at the interim meeting. To my knowledge the draft under discussion was written less than two IETFs ago. I personally was not able to be at all IPnG meetings at the last few IETFs because of conflicts with other things. I have however voiced my concerns about this particular issue to Miek O'Dell while the discussion was going on. But all that is besides the point really.
The reason I ask is because we have done technical analysis on this and have had much discussion.
I have seen some of this discussion. I am afraid I have seen no documented discussion revealing the reasoning behind fixing the TLA length and fixing it at 13 bits. Frankly I have been surprised by the sudden speed of the provider based addressing standardisation. What I have voiced are concerns based on our experience with setting up and operating address space registries as well as providing coordination services to ISPs. My main point is that fixing the TLA length and fixing it at 13 bits has such far-reaching consequences that it needs to be supported by a solid technical argument which I cannot find in the drafts nor in any other source available to me. I think the draft should at least point to a solid reference supporting this. I expect a lot of entropy down the road if this is not supported well.
I think discussing the reason for going with a 13bit TLA needs to be brought out more and doing and checking that is prudent. But the architecture and reasoning has had many technical discussions. I would like to understand as a WG member if you or RIPE did not agree with the results (which I would think we would have heard before now) or if you or RIPE have not been part of these open public discussions. It could be we need to point to the mail archives and the GSE reasoning paper done by Thomas Narten, Lixia Zhang, et al from whence this essential proposal came from based on a WG meeting in Mountain View about a year ago? I am trying to understand if this is an educational effort on our part as a WG group?
It is both educational and principal. Major design decisions should be somewhat transparent to a wider audience. Standardising TLA length in fact puts significant constraints on operations, business models and address space allocation policies just to name a few issues. This needs to be justified somewhat more than just saying "it is standardised like this". The reasons have to be accessible more widely than just the IPnG WG. Note that I am not at issue with the underlying architecture. It is about fixing the boundary and fixing it at a particular value. If there is a solid technical reason for it, then document it. Documenting it will make the standard a stronger document and will prevent a lot of discussion about the repercussions. If there is no solid technical reason to do so then then do not fix these values. If a (proposed) standard does not document this reasoning or at least points to it, it is seriously flawed. This is not a definition of a type field in some application protocol header. It is much more critical. Does that answer your question? Daniel
Daniel, Good answer. I agree. Be helpful in the future if you would state your concerns to the WG directly as we may have been able to have done this before going to the IESG. I recall no mail from Mike O'dell to this list on the TLA issue. But we need to address your concern for sure. I have had many ask about the 13 bit issue and figured that would pop up. thanks /jim
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bound＠zk3.dec.com -
Daniel Karrenberg