> On 18 Dec 2018, at 22:30, Joel Halpern <j...@joelhalpern.com> wrote: > > History of non-contiguous network masks, as I observed it. [snip] > > When we were done, other folks looked at the work (I don't know if the > Internet Drafts are still in repositories, but they shoudl be.) And > concluded that while this would work, no network operations staff would ever > be able to do it correctly. So as a community we decided not to go down that > path.
In the late 1990s I was doing web server things at Demon Internet. Our “Homepages” service provided an IP-based virtual host for each customer (it predated widespread support for HTTP Host: headers), and by the time I joined the service had two /18s and a /16 of web sites (if my memory is correct). We were allocating addresses to customers sequentially, so the /18s were full and the /16 was in progress. We had a small number of front-end Squid reverse proxy caches which owned all the IP addresses, using a BSD kernel hack (which I worked on to get published but it never got committed upstream https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=12071) The problem was that the entirely static load spreading relied on the routing config upstream from the reverse proxies, and IIRC it just divided the space into /18s and allocated them to proxies. So the load allocation was very uneven. I thought up a cunning hack, to divide the /16 by using a non-contiguous netmask of 0xffff0003 instead of 0xffffc000, so that successive customers would be allocated to front ends 0,1,2,3 cyclically. Fun :-) But I observed that one of my colleagues had a CIDR chart stuck on the side of his monitor, and that all the documentation in this area warned of dragons and bugs, and I realised that it would be unwise to do more than try it out experimentally :-) Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at
