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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: multi-homing
On Tue, Aug 28, 2001 at 05:11:51PM -0700, steve uurtamo wrote: > iii) the number of prefixes that _would_ multihome if they: > > a) had the appropriate equipment > b) had the appropriate tech-brains > c) had an ASN > d) had connections through multiple providers > > is _not_ known. It is known. You forget one point, e) find it financially attractive, but all together the upper bound is all sites. There is a good technical argument (in the abstract, not with today's system) to be made that everyone should be multihomed, down to dual-DSL lines, dual-dial up lines, dual whatever access is available. Of course, for a number of reasons this will never happen, most of them come back to it not being financially attractive for the users or for the service providers. If you design everything from the ground up such that each "site" is multihomed by default, and can develop systems that scale to that goal than no matter how many people choose to multihome the system will work. I believe it is technologically possible to make every site requirement. It would never happen with today's protocols, and alias with the direction IPv6 is taking I don't see a light at the end of that tunnel wrt multihoming. The technology may be prohibitively expensive at some cut off point, but at least at that point it would come down to simple dollars and cents for the users and an ISP, and not a maze of similar but slightly different rules. I know someone will want to argue that it is not possible to allow _everyone_ to multihome, so I will go ahead and suggest an example of a network very close to that goal, in fact one you can run IP over (if a tad slowly). The cellular telephone network for the most part has this property. Every phone has a number. It can dynamically connect to multiple providers, and can change providers as conditions change, or the device moves. The only property it doesn't have that IP multihoming doesn't have is the ability to use two providers at the same time; however the technology for a handset that could make a CDMA and a TMDA call at the same time on two different networks definitely exists. This is not to say I think 'cellular phone routing' would solve the IP issues if directly translated, in fact I think quite the opposite. That said, I do belive large scale systems that allow individual users to move, or multihome (I think those two items are more closely related than people think) while keeping their "address" exist. I don't do the IETF thing, but has any development effort there tried to make multihoming / mobility a requirement of a new protocol, and if so why hasn't there been more progress on that front? -- Leo Bicknell - [email protected] Systems Engineer - Internetworking Engineer - CCIE 3440 Read TMBG List - [email protected], www.tmbg.org
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