Hi Teco, You wrote that you did not agree with my statement:
>> For this reason, I think it would be impossible to successfully >> introduce a host-based approach to multihoming in http://www.irtf.org/pipermail/rrg/2008-November/000215.html and you also wrote: > I think multi-homing in edge networks MUST support legacy hosts. I understand this as: if an edge network adopts any kind of scalable routing solution, that the solution must provide 100% support for multihoming for all incoming packets, including those sent by hosts in non-upgraded networks (AKA, for a host-based solution, upgraded hosts). Otherwise, with less than 100% of traffic responding to the multihoming system, it wouldn't be enough use to anybody to make them want to install it. If this is what you meant, I agree with you. > Adding ISP uplinks to single-homed edge networks can be very beneficial. But it requires some kind of scheme to make them useful. Currently, the only way to multihome like this is to get PI space and advertise it into the DFZ through one ISP or the other. As more and more end-user networks do this, so we have the routing scaling problem. > Taking an existing ISP uplink out of service would need more attention, but > don't say this is impossible or not cost-effective. Let's say: it depends. > More important: it can be decided site by site. I haven't been able to understand this clearly, or why you think it a host-based routing scaling solution could pass either set of critiques I (and others) have made: 1 - It would be impossible to deploy it widely enough (in any reasonable time frame) that there were such a proportion of all hosts (such as 95%, 99% or whatever) that the resulting multihoming would actually be useful to anyone who deployed it - this is because a host-based solution only works when both hosts are upgraded. This is especially so if the scheme involves rewriting applications, as well as host stacks. As Brian Carpenter wrote recently: It's clear that once you ask for action by application programmers or non-routine action by end users, the costs become unthinkable. 2 - As I wrote here: Fundamental objections to a host-based scalable routing solution http://www.irtf.org/pipermail/rrg/2008-November/000233.html It would be undesirable to push this functionality out to hosts, compared to handling it with some new architectural structures in the network (that is, the routing and addressing system in the core of the Net and in ISP and end-user networks). - Robin _______________________________________________ rrg mailing list [email protected] https://www.irtf.org/mailman/listinfo/rrg
