- ipv6-wg - mailman.ripe.net

Fw: IAB/IESG Recommendations on IPv6 Address Delegation
by Thomas Trede 03 Sep '00

03 Sep '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: "Steve Deering" <deering(a)cisco.com> To: <ipng(a)sunroof.eng.sun.com> Cc: <ngtrans(a)sunroof.eng.sun.com>; "Bob Hinden" <hinden(a)iprg.nokia.com> Sent: Saturday, September 02, 2000 1:02 AM Subject: Fwd: IAB/IESG Recommendations on IPv6 Address Delegation > Appended below is the message that was sent today to the RIRs from the > IAB and IESG, regarding IPv6 address allocation policy. It contains most > of the material that was in the draft I forwarded here on Sunday, but > reorganized into a more coherent document. > > Steve > > -------- > >Date: Fri, 01 Sep 2000 12:40:48 -0700 > >To: lir-wg(a)ripe.net (RIPE), policy(a)arin.net (ARIN), > > apnic-talk(a)apnic.net (APNIC) > >From: Fred Baker <chair(a)ietf.org> > >Subject: IAB/IESG Recommendations on IPv6 Address Delegation > >Cc: ipv6-directorate(a)sunroof.eng.sun.com, iesg(a)ietf.org, iab(a)ISI.EDU, > > ipv6-wg(a)ripe.net (RIPE), sig-ipv6(a)lists.apnic.net (APNIC) > > > >Folks: > > > >The RIR community asked the IETF community for advice regarding the > >assignment of IPv6 prefixes to service providers and edge networks, both > >with a view to topological address assignment and to multihomed networks. > >The IPv6 Directorate prepared a statement, which the IESG and IAB have > >reviewed and approved. This is attached. > > > >I trust that this answers the questions you asked, and serves as a basis for > >IPv6 deployment in the near term. If you have questions or issues concerning > >it, I would suggest that you address them to the IPv6 Directorate copying > >the IESG and IAB. > > > >We intend to publish an Informational RFC in the near future documenting the > >contents of this note. > > > >Fred Baker > > > >----------------------------------------------------------------------- > > > > IAB/IESG Recommendations on IPv6 Address Allocations > > September 1, 2000 > > > >Introduction > > > >During a discussion between IETF and RIR experts at the Adelaide IETF, > >a suggestion was made that it might be appropriate to allocate /56 > >prefixes instead of /48 for homes and small businesses. However, > >subsequent analysis has revealed significant advantages in using /48 > >uniformly. This note is an update following further discussions at > >the Pittsburgh IETF. > > > >This document was developed by the IPv6 Directorate, IAB and IESG, and > >is a recommendation from the IAB and IESG to the RIRs. > > > >Background > > > >The technical principles that apply to address allocation seek to > >balance healthy conservation practices and wisdom with a certain ease > >of access. On the one hand, when managing the use of a potentially > >limited resource, one must conserve wisely to prevent exhaustion > >within an expected lifetime. On the other hand, the IPv6 address > >space is in no sense as precious a resource as the IPv4 address space, > >and unwarranted conservatism acts as a disincentive in a marketplace > >already dampened by other factors. So from a market development > >perspective, we would like to see it be very easy for a user or an ISP > >to obtain as many IPv6 addresses as they really need without a > >prospect of immediate renumbering or of scaling inefficiencies. > > > >The IETF makes no comment on business issues or relationships. > >However, in general, we observe that technical delegation policy can > >have strong business impacts. A strong requirement of the address > >delegation plan is that it not be predicated on or unduly bias > >business relationships or models. > > > >The IPv6 address, as currently defined, consists of 64 bits of > >"network number" and 64 bits of "host number". The technical reasons > >for this are several. The requirements for IPv6 agreed to in 1993 > >included a plan to be able to address approximately 2^40 networks and > >2^50 hosts; the 64/64 split effectively accomplishes this. Procedures > >used in host address assignment, such as the router advertisement of a > >network's prefix to hosts [RFC 2462], which in turn place a locally > >unique number in the host portion, depend on this split. Examples of > >obvious choices of host number (IEEE Mac Address, E.164 number, E.214 > >IMSI, etc) suggest that no assumption should be made that bits may be > >stolen from that range for subnet numbering; current generation MAC > >layers and E.164 numbers specify up to 64 bit objects. Therefore, > >subnet numbers must be assumed to come from the network part. This is > >not to preclude routing protocols such as IS-IS level 1 (intra-area) > >routing, which routes individual host addresses, but says that it may > >not be depended upon in the world outside that zone. > > > >The IETF has also gone to a great deal of effort to minimize the > >impacts of network renumbering. None-the-less, renumbering of IPv6 > >networks is neither invisible nor completely painless. Therefore, > >renumbering should be considered an acceptable event, but to be > >avoided if reasonably avoidable. > > > >The IETF's IPNG working group has recommended that the address block > >given to a single edge network which may be recursively subnetted be a > > > >48 bit prefix. This gives each such network 2^16 subnet numbers to > >use in routing, and a very large number of unique host numbers within > >each network. This is deemed to be large enough for most enterprises, > >and to leave plenty of room for delegation of address blocks to > >aggregating entities. > > > >It is not obvious, however, that all edge networks are likely to be > >recursively subnetted; an individual PC in a home, or a single cell in > >a mobile telephone network, for example, may or may not be further > >subnetted (depending whether they are acting as, e.g., gateways to > >personal, home, or vehicular networks). When a network number is > >delegated to a place that will not require subnetting, therefore, it > >might be acceptable for an ISP to give a single 64 bit prefix - > >perhaps shared among the dial-in connections to the same ISP router. > >However this decision may be taken in the knowledge that there is > >objectively no shortage of /48s, and the expectation that personal, > >home and vehicle networks will become the norm. Indeed, it is widely > >expected that all IPv6 subscribers, whether domestic (homes), mobile > >(vehicles or individuals), or enterprises of any size, will eventually > >possess multiple always-on hosts, at least one subnet with the > >potential for additional subnetting, and therefore some internal > >routing capability. Note that in the mobile environment, the device > >connecting a mobile site to the network may in fact be a third > >generation cellular telephone. In other words the subscriber > >allocation unit is not always a host; it is always potentially a site. > > > >Address Delegation Recommendations > > > >The RIR communities, with the IAB, have determined that reasonable > >address prefixes delegated to service providers for initial > >allocations should be on the order of 29 to 35 bits in length, giving > >individual delegations support for 2^13 (8K) to 2^19 (512K) subscriber > >networks. Allocations are to be given in a manner such that an > >initial prefix may be subsumed by subsequent larger allocations > >without forcing existing subscriber networks to renumber. We concur > >that this meets the technical requirement for manageable and scalable > >backbone routing while simultaneously allowing for managed growth of > >individual delegations. > > > >The same type of rule could be used in the allocation of addresses in > >edge networks; if there is doubt whether an edge network will in turn > >be subnetted, the edge network might be encouraged to allocate the > >first 64 bit prefix out of a block of 8..256, preserving room for > >growth of that allocation without renumbering up to a point. However, > >for the reasons described below, we recommend use of a fixed boundary > >at /48 for all subscribers except the very largest (who could receive > >multiple /48's), and those clearly transient or otherwise have no > >interest in subnetting (who could receive a /64). Note that there > >seems to be little benefit in not giving a /48 if future growth is > >anticipated. In the following, we give the arguments for a uniform > >use of /48 and then demonstrate that it is entirely compatible with > >responsible stewardship of the total IPv6 address space. > > > >The arguments for the fixed boundary are: > > > > - only by having an ISP-independent boundary can we guarantee that a > > change of ISP will not require a costly internal restructuring or > > consolidation of subnets. > > > > - to enable straightforward site renumbering, i.e., when a site > > renumbers from one prefix to another, the whole process, including > > parallel running of the two prefixes, would be greatly complicated > > if the prefixes had different lengths (depending of course on the > > size and complexity of the site). > > > > - there are various possible approaches to multihoming for IPv6 > > sites, including the techniques already used for IPv4 multihoming. > > The main open issue is finding solutions that scale massively > > without unduly damaging route aggregation and/or optimal route > > selection. Much more work remains to be done in this area, but it > > seems likely that several approaches will be deployed in practice, > > each with their own advantages and disadvantages. Some (but not > > all) will work better with a fixed prefix boundary. (Multihoming > > is discussed in more detail below.) > > > > - to allow easy growth of the subscribers' networks -- no need to > > keep going back to ISPs for more space (except for that relatively > > small number of subscribers for which a /48 is not enough). > > > > - remove the burden from the ISPs and registries of judging sites' > > needs for address space, unless the site requests more space than a > > /48, with several advantages: > > > > - ISPs no longer need to ask for details of their customers' > > network architecture and growth plans > > - ISPs and registries no longer have to judge rates of address > > consumption by customer type > > - registry operations will be made more efficient by reducing the > > need for evaluations and judgements > > - address space will no longer be a precious resource for > > customers, removing the major incentive for subscribers to > > install v6/v6 NATs, which would defeat the ability of IPv6 to > > restore address transparency. > > > > - to allow the site to maintain a single reverse-DNS zone covering > > all prefixes. > > > > - If and only if a site can use the same subnetting structure under > > each of its prefixes, then it can use the same zone file for the > > address-to-name mapping of all of them. And, using the > > conventions of RFC 2874, it can roll the reverse mapping data > > into the "forward" (name-keyed) zone. > > > >Specific advantages of the fixed boundary being at /48 include > > > > - to leave open the technical option of retro-fitting the GSE > > (Global, Site and End-System Designator, a.k.a "8+8") proposal for > > separating locators and identifiers, which assumes a fixed boundary > > between global and site addressing at /48. Although the GSE > > technique was deferred a couple of years ago, it still has strong > > proponents. Also, the IRTF Namespace Research Group is actively > > looking into topics closely related to GSE. It is still possible > > that GSE or a derivative of GSE will be used with IPv6 in the > > future. > > > > - since the site local prefix is fec0::/48, global site prefixes of > > /48 will allow sites to easily maintain a simple 1 to 1 mapping > > between the global topology and the site local topology in the SLA > > field. > > > > - similarly, if the 6to4 proposal is standardized, migration from a > > 6to4 prefix, which is /48 by construction, to a native IPv6 prefix > > will be simplified if the native prefix is /48. > > > >Note that none of these reasons imply an expectation that homes, > >vehicles, etc. will intrinsically require 16 bits of subnet space. > > > >Conservation of Address Space > > > >The question naturally arises whether giving a /48 to every subscriber > >represents a profligate waste of address space. Objective analysis > >shows that this is not the case. A /48 prefix under the Aggregatable > >Global Unicast Address (TLA) format prefix actually contains 45 > >variable bits, i.e., the number of available prefixes is 2**45 or about > >35 trillion (35,184,372,088,832). If we take the limiting case of > >assigning one prefix per human, then the utilization of the TLA space > >appears to be limited to approximately 0.03% on reasonable > >assumptions. > > > >More precisely, > > > > - RFC 1715 defines an "H ratio" based on experience in address space > > assignment in various networks. Applied to a 45 bit address space, > > and projecting a world population of 10.7 billion by 2050 (see > > http://www.popin.org/pop1998/) the required assignment efficiency > > is log_10(1.07*10^10) / 45 = 0.22. This is less than the > > efficiencies of telephone numbers and DECnetIV or IPv4 addresses > > shown in RFC 1715, i.e., gives no grounds for concern. > > > > - We are highly confident in the validity of this analysis, based on > > experience with IPv4 and several other address spaces, and on > > extremely ambitious scaling goals for the Internet amounting to an > > 80 bit address space *per person*. Even so, being acutely aware of > > the history of under-estimating demand, we have reserved more than > > 85% of the address space (i.e., the bulk of the space not under the > > Aggregatable Global Unicast Address (TLA) format prefix). > > Therefore, if the analysis does one day turn out to be wrong, our > > successors will still have the option of imposing much more > > restrictive allocation policies on the remaining 85%. > > > > - For transient use by non-routing hosts (e.g., for stand-alone > > dial-up users who prefer transient addresses for privacy reasons), > > a prefix of /64 might be OK. But a subscriber who wants "static" > > IPv6 address space, or who has or plans to have multiple subnets, > > ought to be provided with a /48, for the reasons given above, even > > if it is a transiently provided /48. > > > >To summarize, we argue that although careful stewardship of IPv6 > >address space is essential, this is completely compatible with the > >convenience and simplicity of a uniform prefix size for IPv6 sites of > >any size. The numbers are such that there seems to be no objective > >risk of running out of space, giving an unfair amount of space to > >early customers, or of getting back into the over-constrained IPv4 > >situation where address conservation and route aggregation damage each > >other. > > > >Multihoming Issues > > > >In the realm of multi-homed networks, the techniques used in IPv4 can > >all be applied, but they have known scaling problems. Specifically, > >if the same prefix is advertised by multiple ISPs, the routing tables > >will grow as a function of the number of multihomed sites. To go > >beyond this for IPv6, we only have initial proposals on the table at > >this time, and active work is under way in the IETF IPNG working > >group. Until existing or new proposals become more fully developed, > >existing techniques known to work in IPv4 will continue to be used in > >IPv6. > > > >Key characteristics of an ideal multi-homing proposal include (at > >minimum) that it provides routing connectivity to any multi-homed > >network globally, conserves address space, produces high quality > >routes at least as well as the single-homed host case previously > >discussed via any of the network's providers, enables a multi-homed > >network to connect to multiple ISPs, does not inherently bias routing > >to use any proper subset of those networks, does not unduly damage > >route aggregation, and scales to very large numbers of multi-homed > >networks. > > > >One class of solution being considered amounts to permanent parallel > >running of two (or more) prefixes per site. In the absence of a fixed > >prefix boundary, such a site might be required to have multiple > >different internal subnet numbering strategies, (one for each prefix > >length) or, if it only wanted one, be forced to use the most > >restrictive one as defined by the longest prefix it received from any > >of its ISPs. In this approach, a multi-homed network would have an > >address block from each of its upstream providers. Each host would > >either have exactly one address picked from the set of upstream > >providers, or one address per host from each of the upstream > >providers. The first case is essentially a variant on RFC 2260, with > >known scaling limits. > > > >In the second case (multiple addresses per host), if two multi-homed > >networks communicate, having respectively m and n upstream providers, > >then the one initiating the connection will select one address pair > >from the n*m potential address pairs to connect from and to, and in so > >doing will select the providers, and therefore the applicable route, > >for the life of the connection. Given that each path will have a > >different ambient bit rate, loss rate, and delay, if neither host is > >in possession of any routing or metric information, the initiating > >host has only a 1/(m*n) probability of selecting the optimal address > >pair. Work on better-than-random address selection is in progress in > >the IETF, but is incomplete. > > > >An existence proof exists in the existing IPv4 Internet that a network > >whose address is distinct from and globally advertised to all upstream > >providers permits the routing network to select a reasonably good path > >within the applicable policy. Present-day routing policies are not > >QoS policies but reachability policies, which means that they will not > >necessarily select the optimal delay, bit rate, or loss rate, but the > >route will be the best within the metrics that are indeed in use. One > >may therefore conclude that this would work correctly for IPv6 > >networks as well, apart from scaling issues. > >=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > >Fred Baker | 519 Lado Drive > >IETF Chair | Santa Barbara California 93111 > >www.ietf.org | Desk: +1-408-526-4257 > > | Mobile: +1-805-886-3873 > > | FAX: +1-413-473-2403 > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to majordomo(a)sunroof.eng.sun.com > -------------------------------------------------------------------- >

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IAB/IESG Recommendations on IPv6 Address Delegation
by Fred Baker 01 Sep '00

01 Sep '00

Folks: The RIR community asked the IETF community for advice regarding the assignment of IPv6 prefixes to service providers and edge networks, both with a view to topological address assignment and to multihomed networks. The IPv6 Directorate prepared a statement, which the IESG and IAB have reviewed and approved. This is attached. I trust that this answers the questions you asked, and serves as a basis for IPv6 deployment in the near term. If you have questions or issues concerning it, I would suggest that you address them to the IPv6 Directorate copying the IESG and IAB. We intend to publish an Informational RFC in the near future documenting the contents of this note. Fred Baker ----------------------------------------------------------------------- IAB/IESG Recommendations on IPv6 Address Allocations September 1, 2000 Introduction During a discussion between IETF and RIR experts at the Adelaide IETF, a suggestion was made that it might be appropriate to allocate /56 prefixes instead of /48 for homes and small businesses. However, subsequent analysis has revealed significant advantages in using /48 uniformly. This note is an update following further discussions at the Pittsburgh IETF. This document was developed by the IPv6 Directorate, IAB and IESG, and is a recommendation from the IAB and IESG to the RIRs. Background The technical principles that apply to address allocation seek to balance healthy conservation practices and wisdom with a certain ease of access. On the one hand, when managing the use of a potentially limited resource, one must conserve wisely to prevent exhaustion within an expected lifetime. On the other hand, the IPv6 address space is in no sense as precious a resource as the IPv4 address space, and unwarranted conservatism acts as a disincentive in a marketplace already dampened by other factors. So from a market development perspective, we would like to see it be very easy for a user or an ISP to obtain as many IPv6 addresses as they really need without a prospect of immediate renumbering or of scaling inefficiencies. The IETF makes no comment on business issues or relationships. However, in general, we observe that technical delegation policy can have strong business impacts. A strong requirement of the address delegation plan is that it not be predicated on or unduly bias business relationships or models. The IPv6 address, as currently defined, consists of 64 bits of "network number" and 64 bits of "host number". The technical reasons for this are several. The requirements for IPv6 agreed to in 1993 included a plan to be able to address approximately 2^40 networks and 2^50 hosts; the 64/64 split effectively accomplishes this. Procedures used in host address assignment, such as the router advertisement of a network's prefix to hosts [RFC 2462], which in turn place a locally unique number in the host portion, depend on this split. Examples of obvious choices of host number (IEEE Mac Address, E.164 number, E.214 IMSI, etc) suggest that no assumption should be made that bits may be stolen from that range for subnet numbering; current generation MAC layers and E.164 numbers specify up to 64 bit objects. Therefore, subnet numbers must be assumed to come from the network part. This is not to preclude routing protocols such as IS-IS level 1 (intra-area) routing, which routes individual host addresses, but says that it may not be depended upon in the world outside that zone. The IETF has also gone to a great deal of effort to minimize the impacts of network renumbering. None-the-less, renumbering of IPv6 networks is neither invisible nor completely painless. Therefore, renumbering should be considered an acceptable event, but to be avoided if reasonably avoidable. The IETF's IPNG working group has recommended that the address block given to a single edge network which may be recursively subnetted be a 48 bit prefix. This gives each such network 2^16 subnet numbers to use in routing, and a very large number of unique host numbers within each network. This is deemed to be large enough for most enterprises, and to leave plenty of room for delegation of address blocks to aggregating entities. It is not obvious, however, that all edge networks are likely to be recursively subnetted; an individual PC in a home, or a single cell in a mobile telephone network, for example, may or may not be further subnetted (depending whether they are acting as, e.g., gateways to personal, home, or vehicular networks). When a network number is delegated to a place that will not require subnetting, therefore, it might be acceptable for an ISP to give a single 64 bit prefix - perhaps shared among the dial-in connections to the same ISP router. However this decision may be taken in the knowledge that there is objectively no shortage of /48s, and the expectation that personal, home and vehicle networks will become the norm. Indeed, it is widely expected that all IPv6 subscribers, whether domestic (homes), mobile (vehicles or individuals), or enterprises of any size, will eventually possess multiple always-on hosts, at least one subnet with the potential for additional subnetting, and therefore some internal routing capability. Note that in the mobile environment, the device connecting a mobile site to the network may in fact be a third generation cellular telephone. In other words the subscriber allocation unit is not always a host; it is always potentially a site. Address Delegation Recommendations The RIR communities, with the IAB, have determined that reasonable address prefixes delegated to service providers for initial allocations should be on the order of 29 to 35 bits in length, giving individual delegations support for 2^13 (8K) to 2^19 (512K) subscriber networks. Allocations are to be given in a manner such that an initial prefix may be subsumed by subsequent larger allocations without forcing existing subscriber networks to renumber. We concur that this meets the technical requirement for manageable and scalable backbone routing while simultaneously allowing for managed growth of individual delegations. The same type of rule could be used in the allocation of addresses in edge networks; if there is doubt whether an edge network will in turn be subnetted, the edge network might be encouraged to allocate the first 64 bit prefix out of a block of 8..256, preserving room for growth of that allocation without renumbering up to a point. However, for the reasons described below, we recommend use of a fixed boundary at /48 for all subscribers except the very largest (who could receive multiple /48's), and those clearly transient or otherwise have no interest in subnetting (who could receive a /64). Note that there seems to be little benefit in not giving a /48 if future growth is anticipated. In the following, we give the arguments for a uniform use of /48 and then demonstrate that it is entirely compatible with responsible stewardship of the total IPv6 address space. The arguments for the fixed boundary are: - only by having an ISP-independent boundary can we guarantee that a change of ISP will not require a costly internal restructuring or consolidation of subnets. - to enable straightforward site renumbering, i.e., when a site renumbers from one prefix to another, the whole process, including parallel running of the two prefixes, would be greatly complicated if the prefixes had different lengths (depending of course on the size and complexity of the site). - there are various possible approaches to multihoming for IPv6 sites, including the techniques already used for IPv4 multihoming. The main open issue is finding solutions that scale massively without unduly damaging route aggregation and/or optimal route selection. Much more work remains to be done in this area, but it seems likely that several approaches will be deployed in practice, each with their own advantages and disadvantages. Some (but not all) will work better with a fixed prefix boundary. (Multihoming is discussed in more detail below.) - to allow easy growth of the subscribers' networks -- no need to keep going back to ISPs for more space (except for that relatively small number of subscribers for which a /48 is not enough). - remove the burden from the ISPs and registries of judging sites' needs for address space, unless the site requests more space than a /48, with several advantages: - ISPs no longer need to ask for details of their customers' network architecture and growth plans - ISPs and registries no longer have to judge rates of address consumption by customer type - registry operations will be made more efficient by reducing the need for evaluations and judgements - address space will no longer be a precious resource for customers, removing the major incentive for subscribers to install v6/v6 NATs, which would defeat the ability of IPv6 to restore address transparency. - to allow the site to maintain a single reverse-DNS zone covering all prefixes. - If and only if a site can use the same subnetting structure under each of its prefixes, then it can use the same zone file for the address-to-name mapping of all of them. And, using the conventions of RFC 2874, it can roll the reverse mapping data into the "forward" (name-keyed) zone. Specific advantages of the fixed boundary being at /48 include - to leave open the technical option of retro-fitting the GSE (Global, Site and End-System Designator, a.k.a "8+8") proposal for separating locators and identifiers, which assumes a fixed boundary between global and site addressing at /48. Although the GSE technique was deferred a couple of years ago, it still has strong proponents. Also, the IRTF Namespace Research Group is actively looking into topics closely related to GSE. It is still possible that GSE or a derivative of GSE will be used with IPv6 in the future. - since the site local prefix is fec0::/48, global site prefixes of /48 will allow sites to easily maintain a simple 1 to 1 mapping between the global topology and the site local topology in the SLA field. - similarly, if the 6to4 proposal is standardized, migration from a 6to4 prefix, which is /48 by construction, to a native IPv6 prefix will be simplified if the native prefix is /48. Note that none of these reasons imply an expectation that homes, vehicles, etc. will intrinsically require 16 bits of subnet space. Conservation of Address Space The question naturally arises whether giving a /48 to every subscriber represents a profligate waste of address space. Objective analysis shows that this is not the case. A /48 prefix under the Aggregatable Global Unicast Address (TLA) format prefix actually contains 45 variable bits, i.e., the number of available prefixes is 2**45 or about 35 trillion (35,184,372,088,832). If we take the limiting case of assigning one prefix per human, then the utilization of the TLA space appears to be limited to approximately 0.03% on reasonable assumptions. More precisely, - RFC 1715 defines an "H ratio" based on experience in address space assignment in various networks. Applied to a 45 bit address space, and projecting a world population of 10.7 billion by 2050 (see http://www.popin.org/pop1998/) the required assignment efficiency is log_10(1.07*10^10) / 45 = 0.22. This is less than the efficiencies of telephone numbers and DECnetIV or IPv4 addresses shown in RFC 1715, i.e., gives no grounds for concern. - We are highly confident in the validity of this analysis, based on experience with IPv4 and several other address spaces, and on extremely ambitious scaling goals for the Internet amounting to an 80 bit address space *per person*. Even so, being acutely aware of the history of under-estimating demand, we have reserved more than 85% of the address space (i.e., the bulk of the space not under the Aggregatable Global Unicast Address (TLA) format prefix). Therefore, if the analysis does one day turn out to be wrong, our successors will still have the option of imposing much more restrictive allocation policies on the remaining 85%. - For transient use by non-routing hosts (e.g., for stand-alone dial-up users who prefer transient addresses for privacy reasons), a prefix of /64 might be OK. But a subscriber who wants "static" IPv6 address space, or who has or plans to have multiple subnets, ought to be provided with a /48, for the reasons given above, even if it is a transiently provided /48. To summarize, we argue that although careful stewardship of IPv6 address space is essential, this is completely compatible with the convenience and simplicity of a uniform prefix size for IPv6 sites of any size. The numbers are such that there seems to be no objective risk of running out of space, giving an unfair amount of space to early customers, or of getting back into the over-constrained IPv4 situation where address conservation and route aggregation damage each other. Multihoming Issues In the realm of multi-homed networks, the techniques used in IPv4 can all be applied, but they have known scaling problems. Specifically, if the same prefix is advertised by multiple ISPs, the routing tables will grow as a function of the number of multihomed sites. To go beyond this for IPv6, we only have initial proposals on the table at this time, and active work is under way in the IETF IPNG working group. Until existing or new proposals become more fully developed, existing techniques known to work in IPv4 will continue to be used in IPv6. Key characteristics of an ideal multi-homing proposal include (at minimum) that it provides routing connectivity to any multi-homed network globally, conserves address space, produces high quality routes at least as well as the single-homed host case previously discussed via any of the network's providers, enables a multi-homed network to connect to multiple ISPs, does not inherently bias routing to use any proper subset of those networks, does not unduly damage route aggregation, and scales to very large numbers of multi-homed networks. One class of solution being considered amounts to permanent parallel running of two (or more) prefixes per site. In the absence of a fixed prefix boundary, such a site might be required to have multiple different internal subnet numbering strategies, (one for each prefix length) or, if it only wanted one, be forced to use the most restrictive one as defined by the longest prefix it received from any of its ISPs. In this approach, a multi-homed network would have an address block from each of its upstream providers. Each host would either have exactly one address picked from the set of upstream providers, or one address per host from each of the upstream providers. The first case is essentially a variant on RFC 2260, with known scaling limits. In the second case (multiple addresses per host), if two multi-homed networks communicate, having respectively m and n upstream providers, then the one initiating the connection will select one address pair from the n*m potential address pairs to connect from and to, and in so doing will select the providers, and therefore the applicable route, for the life of the connection. Given that each path will have a different ambient bit rate, loss rate, and delay, if neither host is in possession of any routing or metric information, the initiating host has only a 1/(m*n) probability of selecting the optimal address pair. Work on better-than-random address selection is in progress in the IETF, but is incomplete. An existence proof exists in the existing IPv4 Internet that a network whose address is distinct from and globally advertised to all upstream providers permits the routing network to select a reasonably good path within the applicable policy. Present-day routing policies are not QoS policies but reachability policies, which means that they will not necessarily select the optimal delay, bit rate, or loss rate, but the route will be the best within the metrics that are indeed in use. One may therefore conclude that this would work correctly for IPv6 networks as well, apart from scaling issues. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Fred Baker | 519 Lado Drive IETF Chair | Santa Barbara California 93111 www.ietf.org | Desk: +1-408-526-4257 | Mobile: +1-805-886-3873 | FAX: +1-413-473-2403

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Fw: I-D ACTION:draft-ietf-ipngwg-icmp-name-lookups-07.txt
by Thomas Trede 01 Sep '00

01 Sep '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: <Internet-Drafts(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Wednesday, August 30, 2000 12:49 PM Subject: I-D ACTION:draft-ietf-ipngwg-icmp-name-lookups-07.txt > A New Internet-Draft is available from the on-line Internet-Drafts directories. > This draft is a work item of the IPNG Working Group of the IETF. > > Title : IPv6 Node Information Queries > Author(s) : M. Crawford > Filename : draft-ietf-ipngwg-icmp-name-lookups-07.txt > Pages : 14 > Date : 29-Aug-00 > > This document describes a protocol for asking an IPv6 node to supply > certain network information, such as its fully-qualified domain > name. IPv6 implementation experience has shown that direct queries > for a DNS name are useful, and a direct query mechanism for other > information has been requested. > > A URL for this Internet-Draft is: > http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-icmp-name-lookups-07.t xt > > Internet-Drafts are also available by anonymous FTP. Login with the username > "anonymous" and a password of your e-mail address. After logging in, > type "cd internet-drafts" and then > "get draft-ietf-ipngwg-icmp-name-lookups-07.txt". > > A list of Internet-Drafts directories can be found in > http://www.ietf.org/shadow.html > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt > > > Internet-Drafts can also be obtained by e-mail. > > Send a message to: > mailserv(a)ietf.org. > In the body type: > "FILE /internet-drafts/draft-ietf-ipngwg-icmp-name-lookups-07.txt". > > NOTE: The mail server at ietf.org can return the document in > MIME-encoded form by using the "mpack" utility. To use this > feature, insert the command "ENCODING mime" before the "FILE" > command. To decode the response(s), you will need "munpack" or > a MIME-compliant mail reader. Different MIME-compliant mail readers > exhibit different behavior, especially when dealing with > "multipart" MIME messages (i.e. documents which have been split > up into multiple messages), so check your local documentation on > how to manipulate these messages. > > > Below is the data which will enable a MIME compliant mail reader > implementation to automatically retrieve the ASCII version of the > Internet-Draft. >

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Fw: Last Call: IPv6 Node Information Queries to Proposed Standard
by Thomas Trede 01 Sep '00

01 Sep '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: "The IESG" <iesg-secretary(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Thursday, August 31, 2000 6:36 PM Subject: Last Call: IPv6 Node Information Queries to Proposed Standard > > The IESG has received a request from the IPNG Working Group to consider > IPv6 Node Information Queries > <draft-ietf-ipngwg-icmp-name-lookups-07.txt> as a Proposed Standard. > > The IESG plans to make a decision in the next few weeks, and solicits > final comments on this action. Please send any comments to the > iesg(a)ietf.org or ietf(a)ietf.org mailing lists by September 13, 2000. > > Files can be obtained via > http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-icmp-name-lookups-07.t xt > > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to majordomo(a)sunroof.eng.sun.com > -------------------------------------------------------------------- >

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Fw: Request to Advance "IPv6 Node Information Queries"
by Thomas Trede 30 Aug '00

30 Aug '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: "Bob Hinden" <hinden(a)iprg.nokia.com> To: <narten(a)raleigh.ibm.com>; <Erik.Nordmark(a)eng.sun.com> Cc: <scoya(a)ietf.org>; <deering(a)cisco.com>; <ipng(a)sunroof.eng.sun.com> Sent: Wednesday, August 30, 2000 4:33 PM Subject: Request to Advance "IPv6 Node Information Queries" > Erik, Thomas, > > The chairs of the IP Next Generation working group, on behalf of the > working group, request that the following document be published as an > Proposed Standard: > > Title : IPv6 Node Information Queries > Author(s) : M. Crawford > Filename : draft-ietf-ipngwg-icmp-name-lookups-07.txt > Pages : 14 > Date : 29-Aug-00 > > A working group last call for this document was completed on August 16, > 2000. The -07 version of the draft resolves issues raised during the last > call. > > Bob Hinden / Steve Deering > IPng Working Group Co-Chairs > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to majordomo(a)sunroof.eng.sun.com > -------------------------------------------------------------------- >

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Fw: I-D ACTION:draft-ietf-ipngwg-icmp-name-lookups-07.txt
by Thomas Trede 30 Aug '00

30 Aug '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: <Internet-Drafts(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Wednesday, August 30, 2000 12:49 PM Subject: I-D ACTION:draft-ietf-ipngwg-icmp-name-lookups-07.txt > A New Internet-Draft is available from the on-line Internet-Drafts directories. > This draft is a work item of the IPNG Working Group of the IETF. > > Title : IPv6 Node Information Queries > Author(s) : M. Crawford > Filename : draft-ietf-ipngwg-icmp-name-lookups-07.txt > Pages : 14 > Date : 29-Aug-00 > > This document describes a protocol for asking an IPv6 node to supply > certain network information, such as its fully-qualified domain > name. IPv6 implementation experience has shown that direct queries > for a DNS name are useful, and a direct query mechanism for other > information has been requested. > > A URL for this Internet-Draft is: > http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-icmp-name-lookups-07.t xt > > Internet-Drafts are also available by anonymous FTP. Login with the username > "anonymous" and a password of your e-mail address. After logging in, > type "cd internet-drafts" and then > "get draft-ietf-ipngwg-icmp-name-lookups-07.txt". > > A list of Internet-Drafts directories can be found in > http://www.ietf.org/shadow.html > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt > > > Internet-Drafts can also be obtained by e-mail. > > Send a message to: > mailserv(a)ietf.org. > In the body type: > "FILE /internet-drafts/draft-ietf-ipngwg-icmp-name-lookups-07.txt". > > NOTE: The mail server at ietf.org can return the document in > MIME-encoded form by using the "mpack" utility. To use this > feature, insert the command "ENCODING mime" before the "FILE" > command. To decode the response(s), you will need "munpack" or > a MIME-compliant mail reader. Different MIME-compliant mail readers > exhibit different behavior, especially when dealing with > "multipart" MIME messages (i.e. documents which have been split > up into multiple messages), so check your local documentation on > how to manipulate these messages. > > > Below is the data which will enable a MIME compliant mail reader > implementation to automatically retrieve the ASCII version of the > Internet-Draft. >

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Fw: Last Call: Extensions to IPv6 Neighbor Discovery for Inverse Discovery Specification to Proposed Standard
by Thomas Trede 30 Aug '00

30 Aug '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: "The IESG" <iesg-secretary(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Monday, August 28, 2000 5:30 PM Subject: Last Call: Extensions to IPv6 Neighbor Discovery for Inverse Discovery Specification to Proposed Standard > > The IESG has received a request from the IPNG Working Group to consider > Extensions to IPv6 Neighbor Discovery for Inverse Discovery > Specification <draft-ietf-ion-ipv6-ind-04.txt> as a Proposed Standard. > > The IESG plans to make a decision in the next few weeks, and solicits > final comments on this action. Please send any comments to the > iesg(a)ietf.org or ietf(a)ietf.org mailing lists by September 8, 2000. > > Files can be obtained via > http://www.ietf.org/internet-drafts/draft-ietf-ion-ipv6-ind-04.txt > > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to majordomo(a)sunroof.eng.sun.com > -------------------------------------------------------------------- >

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Fw: Last Call: IP Version 6 Management Information Base for the Multicast Listener Discovery Protocol to Proposed Standard
by Thomas Trede 30 Aug '00

30 Aug '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: "The IESG" <iesg-secretary(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Monday, August 28, 2000 5:09 PM Subject: Last Call: IP Version 6 Management Information Base for the Multicast Listener Discovery Protocol to Proposed Standard > > The IESG has received a request from the IPNG Working Group to consider > IP Version 6 Management Information Base for the Multicast Listener > Discovery Protocol <draft-ietf-ipngwg-mld-mib-04.txt> as a Proposed > Standard. > > The IESG plans to make a decision in the next few weeks, and solicits > final comments on this action. Please send any comments to the > iesg(a)ietf.org or ietf(a)ietf.org mailing lists by September 8, 2000. > > Files can be obtained via > http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-mld-mib-04.txt > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to majordomo(a)sunroof.eng.sun.com > -------------------------------------------------------------------- >

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Fw: I-D ACTION:draft-ietf-ipngwg-ipv6multihome-with-aggr-01.txt
by Thomas Trede 30 Aug '00

30 Aug '00

FYI. Regards, Thomas Trede ----- Original Message ----- From: <Internet-Drafts(a)ietf.org> To: <IETF-Announce: ;> Cc: <ipng(a)sunroof.eng.sun.com> Sent: Friday, August 25, 2000 12:43 PM Subject: I-D ACTION:draft-ietf-ipngwg-ipv6multihome-with-aggr-01.txt > A New Internet-Draft is available from the on-line Internet-Drafts directories. > This draft is a work item of the IPNG Working Group of the IETF. > > Title : IPv6 Multihoming with Route Aggregation > Author(s) : J. Yu > Filename : draft-ietf-ipngwg-ipv6multihome-with-aggr-01.txt > Pages : 7 > Date : 24-Aug-00 > > With the growing requirements for reliable Internet connectivity, > increasing number of enterprises choose to acquire Internet > connectivity from more than one Internet Service Providers (ISPs) for > the purpose of connectivity redundancy and traffic load distribution. > The potential of large number of multi-connection sites impose direct > challenge on routing aggregation and consequently on scalability of > the global Internet routing. Hence a solution is highly desirable > which provides the benefit of multi-connection as well as the better > scalability of the global routing system. In addition, such solution > needs to be simple enough to be operationally manageable. With the > fast growth of ISP networks as well as enterprise networks, network > manageability is becoming an increasingly important requirement. This > document describes a solution which achieves the stated goals. > > A URL for this Internet-Draft is: > http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-ipv6multihome-with-agg r-01.txt > > Internet-Drafts are also available by anonymous FTP. Login with the username > "anonymous" and a password of your e-mail address. After logging in, > type "cd internet-drafts" and then > "get draft-ietf-ipngwg-ipv6multihome-with-aggr-01.txt". > > A list of Internet-Drafts directories can be found in > http://www.ietf.org/shadow.html > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt > > > Internet-Drafts can also be obtained by e-mail. > > Send a message to: > mailserv(a)ietf.org. > In the body type: > "FILE /internet-drafts/draft-ietf-ipngwg-ipv6multihome-with-aggr-01.txt". > > NOTE: The mail server at ietf.org can return the document in > MIME-encoded form by using the "mpack" utility. To use this > feature, insert the command "ENCODING mime" before the "FILE" > command. To decode the response(s), you will need "munpack" or > a MIME-compliant mail reader. Different MIME-compliant mail readers > exhibit different behavior, especially when dealing with > "multipart" MIME messages (i.e. documents which have been split > up into multiple messages), so check your local documentation on > how to manipulate these messages. > > > Below is the data which will enable a MIME compliant mail reader > implementation to automatically retrieve the ASCII version of the > Internet-Draft. >

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draft agenda (v1) for IPv6 working group RIPE37
by David Kessens 24 Aug '00

24 Aug '00

Hi, Below follows the first draft of the IPv6 wg agenda. Please let me know if you have any other topics that you want to have discussed or if you have other comments on this first draft of the agenda. I am still looking for volunteers to cover some of the topics as proposed in the agenda. Please let me know if you are willing to take care of one of these. As an experiment, I would like to try whether we can have a presentation at every working group session on one specific ipv6 topic of the ipv6 ietf specifications. This time, I would like to propose the topic of transition mechanisms and in particular 6over4 and 6to4. Please let me know if you are willing to do a presentation on that topic, or if you would be willing to cover another specific topic instead. In addition to the ipv6 wg meeting, we have arranged for another joint lir/ipv6 wg session where we will be able to discuss ipv6 address allocation policies. Note that both Steve Deering and Bob Hinden are planning to be at the RIPE meeting and they will be given a chance to give the IETFs viewpoint on this matter. We don't have an agenda for that meeting yet, but feel free to send me suggestions for topics. Thanks, David K. --- Proposed Agenda (draft v1) for the IPv6 Working Group Meeting RIPE37, September 2000, Amsterdam A. Administrative stuff - appointment of scribe - agenda bashing (David Kessens) B. Status of 6bone (David Kessens) C. News from the IPv6 forum and meeting in Telluride (Juergen Rauschenbach) D. Transition mechanisms (I am looking for a volunteers) E. Addressing plans in the real world (I am looking for volunteers - Bernard Tuy ?!? Wilfried ?!?) F. European developments/initiatives regarding IPv6 (input from the audience) Z. AOB ---

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