I have to deal with the slightly annoying ETSI racks also sometimes called 21 inch racks. As a french invention it is naturally not actually 21 inches but 500 mm between inside of rails and 535 mm outside, with 535 mm being very close to 21 inches.
Although I love the idea of using metric all I ever do is installing adapters, so I can mount 19 inch rack equipment. A waste really. Regards Baldur man. 30. mar. 2020 23.49 skrev Shawn L via NANOG <nanog@nanog.org>: > That's a tough one. In the telco space, the common sizes are 19" and > 23". 19" for gear, 23" for fiber patch panels, etc. There are also some > 25" floating around (Nortel, I'm looking at you). > > > > Unfortunately, 19" gear fits in 19" racks. It fits in 23" sometimes -- if > the manufacture makes both size ears, or you have to use an adapter plate, > which can be a pain, and expensive (for 25" you may as well find a local > machine shop to make them for you, or it's cheaper to remove them and start > over). > > > > Sometimes you can do 19" gear and 23" cable management in a 23" rack, > which is nice. There is also the telco proclivity to attach stand-offs on > the back side of the rack for vertical cabling, which can take up even more > space. > > > > The one thing you really can't do is take servers, etc. designed for a > cabinet or 4-post style rack and put them in a 2-post neatly. There's > adapters and things, but they're a pain as well. At least with a 4-post > square-hole rack you can get 80% of what you want to fit. > > > -----Original Message----- > From: "Coy Hile" <coy.h...@coyhile.com> > Sent: Monday, March 30, 2020 5:31pm > To: "Karsten Elfenbein" <karsten.elfenb...@gmail.com> > Cc: "NANOG" <nanog@nanog.org> > Subject: Re: rack rails > > > > > On Mar 30, 2020, at 5:24 PM, Karsten Elfenbein < > karsten.elfenb...@gmail.com> wrote: > > > > Hi, > > > > something like https://www.opencompute.org/projects/rack-and-power > > comes into my mind for that. > > Mounting on 4 posts should be the default. It is insane what some > > vendors want to mount on 2 posts only. > > > > That brings up an interesting question. As I understand it, the penchant > for two-post mounts come from what are at least colloquially termed telco > racks that are or were common when you had tons of modem banks and such. > Are such mounts — much like DC power — still quite common in the service > provider space, or do most use more or less normal racks? (That said, the > 750mm wide (29.5in) racks that actually have room for high density cables > inside the rack seem much more useful for a networking application than the > 600mm wide version.) > > > > -- > Coy Hile > coy.h...@coyhile.com > > > > >
