At the very minimum use bidirectional modules so you will have four channels. That way you would only have 15 switches on a chain. Also be sure to configured your STP weight so the cut will be in the middle. So one fiber will normally be transmitting to 7 switches, the other fiber to the other 8 switches.
This is still inferior to the WDM solutions proposed, but I fear you have multimode fiber and might not have that choice. Regards, Baldur On Wed, Feb 26, 2020 at 3:33 AM Norman Jester <n...@jester.mx> wrote: > I’m in the process of choosing hardware > for a 30 story building. If anyone has experience with this I’d appreciate > any tips. > > There are two fiber pairs running up the building riser. I need to put a > POE switch on each floor using this fiber. > > The idea is to cut the fiber at each floor and insert a switch and daisy > chain the switches together using one pair, and using the other pair as the > failover side of the ring going back to the source so if one device fails > it doesn’t take the whole string down. > > The problem here is how many switches can be strung together and I would > not try more than 3 to 5. This is not something I typically do (stacking > switches). I have fears of STP and/or RSTP issue stacking past Ethernet > switch to switch limits (if they still exist??) > > Is there a device with a similar protocol as the old 3com (now HP IDF) > stacking capability via fiber? > > I’d like to use something inexpensive as its to power ubiquiti wifi on > each floor. Ideally if you know something I don’t about ubiquiti switches > that can do this I’d appreciate knowing. > > Norman > >