Short version: A taxonomy of different types of end-user network including massive adoption of mobile devices in the foreseeable future.
Large IPv4 networks doing whatever they can to keep using IPv4. Government-mandated adoption of IPv4 by many larger networks would contribute to the IPv6 scaling problem - but may not actually advance genuine IPv6 adoption. Hi Eric, Thanks for your appreciative message: EF> The argument that we are rapidly running out of IPv4 addresses has EF> always been a significant concern for me personally. New deployments EF> (e.g., civil aviation's ATN IPS) and certain industries that have vast EF> numbers of networked devices (e.g., electrical power EF> industry) are excellent candidates to adopt IPv6 for this very reason. EF> However, for the majority of end users, I expect us to prefer to EF> indefinitely use IPv4 by leveraging map-and-encaps techniques such as EF> RANGER, despite the fact that RANGER is part of the effort to support EF> a clean migration to IPv6. > >> I agree with all this, except I would use the term Core-Edge Separation >> architectures, and at present I think LISP and Ivip are a better solution >> than RANGER for either IPv4 or IPv6. > I value your articulate insights, Robin. > > You apparently read the above paragraph of mine as trying to > comment on the technology choice confronting the RRG. No - I was focused on the main body of what you wrote, not the mention of map-and-encaps (CES) and RANGER at the end. My interpretation was that your main points were: 1 - End-user networks which need massive numbers of IP devices and which are installing all new hardware and software to achieve this are likely to adopt IPv6. (I think this is particularly the case with wireless linked utility meters which are not required to be publicly accessible, don't handle large numbers of packets and don't need to communicate with all hosts on the IPv4 Internet.) 2 - Most end-users - who are using the IPv4 Internet day-to-day and who need to be able to communicate with any other host which is involved in global communications (and all such hosts today use IPv4) - will do whatever they can to keep using IPv4, rather than attempt to adopt IPv6 to the exclusion of IPv4. This is because the IPv6 Internet doesn't have the most important property of the IPv4 Internet: that everyone who wants to use Internet communications is using this Internet. 3 - That a successful Core-Edge Elimination architecture (these were previously known as map-and-encaps) would enable a more intensive use of IPv4 address space - and therefore enable more continued use of IPv4 than would otherwise be the case. A agree with all this, and wanted to signal this while at the same time noting that I didn't think RANGER was the best example of a successful Core-Edge Elimination architecture. What you wrote was primarily about what und-user networks would do - and I think with an implication that a CES architecture should be chosen (which I agree with) and with RANGER as an example of such an architecture - which it is. > Rather, I was explaining what the large end user has a very high > probability of doing concerning the issues that the RRG is > considering. This is a different topic, since I believe that the > RRG is primarily oriented to ISPs and largely lacks the large end > user viewpoint. I think the RRG would benefit from having a lot more hands on deck - especially from ISPs and end-users of all types, from universities and corporations, to small businesses, mobile operators and companies which might be interested in providing global mobility via the TTR approach. It is hard for me to say whether ISPs are overly represented in the RRG. My biggest concern, in addition to general lack of people who are prepared to read and constructively discuss a variety of proposals, is that there are a number of people who think it is both practical and desirable to rewrite all existing Internet applications to support the Locator / Identifier Separation naming model which they prefer. This is what all CEE architectures do - though they do so in differing ways. Loc/ID separation is more flexible than the current naming model of the Internet - and to these people more architecturally correct. However I think it will slow down the establishment of Internet communications, and exacerbate the problems of battery-powered hosts on slow, high-latency, less than 100% reliable wireless links. CEE takes the load off the routing system. If CEE was universally adopted then there would be no more need for PI space. All hosts would be using portable Identifiers and there would be no need for PI space - since portability, multihoming and inbound TE would work fine with CEE with each end-user network using one or more PA prefixes. Once CEE was universally adopted, we can keep the current routers, BGP and the DFZ just as they are. Until it is universally adopted, PI prefixes will remain the only way of providing portability and/or multihoming. CEE involves burdening all hosts with extra work so the routing system doesn't need to be altered. It also involves all applications being modified - many of them substantially or radically - for CEE. It also involves a universal abandonment of IPv4 and the adoption not just of IPv6, but of the CEE-enhanced IPv6. Most CEE protocols assume the use of IPv6, because there is room to put both the Identifier and Locator in the one IPv6 address. This does not work with IPv4. A more fundamental problem is that multihoming with CEE involves using double the global unicast address space, or triple if three upstream ISPs are used. This is never going to be practical in IPv4. So not only must all applications be rewritten, they must be moved to this modified version of IPv6, and all user's Internet access services will need to support IPv6 as well. All this to take the load off the routing system and use a naming model which some people regard as more elegant or architecturally correct. I think the routing system should serve the needs of hosts - and that the current naming model is better than that of Locator / Identifier Separation. > Large end users with an adequate supply of IPv4 addresses have a > strong business motivation to maintain their network infrastructure > "as is". Yes - and this is in addition to the absolute requirement, for pretty much all end-users, that their Internet service enables them to communicate with all other Internet users. I think there are two broad types of end-user now and a third in the near future: 1 - Those who can do what they want when their hosts are behind IPv4 NAT. This includes most of what home and SOHO users do today, and a great deal of what all other end-users, do since email, WWW, instant messenger, file upload to public sites and SSH to public sites all work fine from behind NAT. To the extent that these people want or need a web site, they usually find it best to get a cheap hosting arrangement whereby another end-user company runs a virtual server for them. It seems that everyone and their dog (an Aussie term, but literally true in some cases) has a Facebook or MySpace page, and this serves their needs for an easily updated WWW page, without any fuss or expense with domain names or running their own virtual server. These people are generally perfectly well served by existing single-homed DSL etc. services, with a single IPv4 address and their own NAT router (though 99% don't know or understand what NAT means). However, I think a significant number of these end-users rely on port-forwarding from the single IP address their home or office is given. This means they wouldn't be able to run certain applications which are important to them if the port number is fixed for the application and if the address they get is behind a NAT box in the ISP. That NAT box will have one global unicast address and won't be able to satisfy the port forwarding requirements of the multiple customers which access the Net through the box. So these people do fine with a single IPv4 global unicast address per home or office - and DHCP allocation of the address is fine. They generally don't need a fixed address, though it might be convenient for many if they did, since they could use port forwarding to, run their own web server, game server etc. They don't need portability - since it is not too difficult to change any DNS they have on the rare occasions when they choose another ISP. 2 - Those who need stable, reliable, public IP addresses to run mail-servers, web-servers which they host on their own premises, VPN access from other sites and their staff to the local network etc. a - Some of these can do all this with a single IPv4 address. I can do all this with a GNU-Linux box doing NAT, WWW, DNS, SMTP, IMAP, SSH etc - all running from a single fixed IPv4 address. My DSL service is highly reliable (I don't recall an outage in nearly 4 years) and I don't really need portability or multihoming. I don't need portability or multihoming, since the multihoming arrangements could scarcely be more reliable than the service I already get, and it would be easy to change my DNS to move to a new IPv4 address if I chose another ISP. b - Other end-user networks which can do what they want with a single IPv4 address per physical site, but which want/need portability and mulithoming. If I was running a more substantial business, especially one where I ran my own TLS site for credit card transactions and other important customer contact purposes, I would want multihoming. Even if these end-users have a substantial network, this will mainly be of hosts behind NAT. With a single IPv4 address many of them wouldn't really want or need portability - but others would. This would be particularly the case if they had multiple sites and relied on the IPv4 address of each site for VPN connections - and didn't want to rework all their connections whenever one of their hundreds of shops, branch offices etc. chose a new ISP. c - End-user networks with substantial networks who need larger amounts of global unicast IPv4 address space - beyond a handful of IPv4 addresses. These end-users want/need portability, multihoming and probably inbound TE. These organisations range from schools, companies with more than a handful of employees, through universities, corporations etc. right up to the largest multinational companies. The larger ones get it now, with their own PI space. The remainder are not getting it - and this is the part of the routing scaling problem which is hardest to measure. Most of these end-user networks which don't yet have PI space could probably work perfectly well from a much smaller amount of space than 256 IP addresses. Quite a few of them could probably function OK with a single IPv4 address. For instance, a company with a chain of hundreds or thousands of shops or small offices all over the world could probably run fine with each such office or shop having a single IPv4 address Even amongst those with PI space, the huge popularity of the smallest chunk available (256 IPv4 addresses in a /24 prefix) indicates that many or most of them would probably get by with significantly less than 256 addresses. 3 - In addition, in the foreseeable future, there are going to be billions of end-users with IP-capable "cell-phones" - or whatever such things will be known as - including things which are general purpose computing devices, hand-held or laptop. I think these end-users are like the first group, except that they are generally not going to be running their own WWW, mail or game-servers on their cell-phone. There's no way of giving most of these end-users their own IPv4 global unicast address space, but I figure they could all get IPv4 access via NAT. They could all be given their own IPv6 global unicast /64, or their own global unicast IPv6 IP address, but these would change every time they got a new connection to whatever access networks they were using. When using wired Ethernet or using WiFi, at home, or in the office, these cellphones laptops and probably iPads etc. would probably get an IPv4 address behind NAT. With a TTR Mobility system in which the MN could tunnel to TTRs with either IPv4 or IPv6, and with the TTR system using both the IPv4 and IPv6 CES systems, then all these end-users could have their own globally mobile, IPv6 space (such as a /64 or a single IPv6 address). A subset of them could have their own globally mobile IPv4 address - since there aren't enough IPv4 addresses for all 5 billion 10 billion or whatever such mobile devices. I think you were referring to the larger end-user networks which roughly fit my 2c classification. > The only thing that I can see changing this is if a "killer > app" requires the use of IPv6, but thus far no such "killer app" > has appeared except in niche contexts (e.g., smart grid, ATN IPS). Can you suggest any pages with good overviews of the Aeronautical Telecommunications Network (ATN)? I understand it is OSI-based, but that the IPS (Internet Protocol Suite) is an important alternative. There's nothing in the IPv6 protocols which seems to be superior to IPv4 from the point of view of most "applications", when thinking of an "application" as a piece of software running on a PC or server. I think there is more Mobile IP support for IPv6. Better mobility support and no effective limits on public and private address space are also important in some "applications" - in a more expansive use of the term to cover entire global systems, such as the ATN. > Should one appear, then IPv6 will be deployed as needed and the > network infrastructure will be modified to accommodate it. Is this happening with ATN/IPS? > By contrast, should external business relationships or government > decrees require IPv6, then the end users' externally facing network > will support IPv6 but the internal infrastructure itself is > unlikely to change. OK. I am wary of government mandates pushing larger organisations to adopt IPv6 or whatever. Some think that they can afford the whatever this costs - but ordinary people collectively pay for all these organisations' expenses through taxation or by directly or indirectly paying for their services. > Large end users lacking an adequate supply of IPv4 addresses for > their continued growth are also likely to remain IPv4-only in a > similar manner for parallel reasons. There are many map-and-encaps > technologies that enable end users to retain IPv4 indefinitely in > combination with private addresses. I only mentioned RANGER because > I believe that it is a clean alternative. I don't see how a CES system such as RANGER, LISP or Ivip can indefinitely meet the needs of end-user networks which require more global unicast addresses. NAT can already give client-style access to IPv4 Internet - and that has nothing to do with a CES architecture. A CES architecture will enable each physical site of a large organisation to get one or any number of IPv4 addresses, in a stable, portable and multihomable fashion, via any one or more ISPs being used for connectivity. This will be more flexible and will be less expensive than the current practice of each site advertising a /24 - which chews a whole 256 IPv4 addresses, even when only one or a few are needed at each site. So I expect a good CES solution will enable a much greater utilization of IPv4 address space. But this is not an indefinite solution, because the 3.7 billion addresses may be too few, at some stage in the future, for the wants/needs of all Internet users. It is easy to imagine 3 billion, 6 billion or whatever IP-based cellphones which ideally would have their own IPv4 address, globally portable, via TTR Mobility. That can't happen. I guess that some people will get their own globally mobile IPv4 address and the rest will make do with NATed IPv4 access. If they want globally mobile address space for their cellphone - which would allow direct application protocols between these devices and non-mobile networks at home, also with IPv6 space - then there would be no problem providing this via TTR Mobility. > Of course, should senior management become convinced to bear the > expense to internally support IPv6 for patriotic or other > non-business reasons, then this analysis will not pertain to that > particular company. In which case the shareholders will have some interesting questions for them . . . > Mergers and acquisitions are a special case that should worry the > RRG because of the possibility of companies externally advertising > multiple discontinuous PI address spaces. Of course, such issues > already exist for corporations using pre-CIDR addresses. >From the point of view of maximising IPv4 address utilization, we might expect a pair of merged companies to consolidate their usage and while leaving some room for expansion (and other acquisitions) probably be able to return some of the PI space the previously two companies were using. However, it would be a lot of work - and maybe it is best to think of large companies as modular units, not bonded together by interdependence on shared address space and overly entangled networks. Untangling a sub-division from the corporate address space and preparing it for sale to another company sounds like a disruptive and expensive process. > Should governments push IPv6, then the issues confronting the RRG > will become more problematic due to the need to externally route a > combination of IPv4 and IPv6 for corporations that solely use IPv4 > today and who will probably continue to only use IPv4 internally in > the future. Yes, since a properly written regulation would surely require all corporations, universities or whatever above some size limit to get their own PI space, advertise it in the DFZ and demonstrate that their networks (PCs? laser printers?) were fully IPv6 capable. Affirmative action for IPv6 . . . - Robin _______________________________________________ rrg mailing list rrg@irtf.org http://www.irtf.org/mailman/listinfo/rrg