The massive deployments of FTTH around the globe (now tens of millions of end points per quarter) have been responsible for driving price points for singlemode optics down considerably, and it's only going to get a lot cheaper over time before bottoming out. Plan to the trajectory, not the history. OM3 & OM4 MMF will provide considerably greater reach than their forebears, but if you're looking to centralize servers and avoid myriad intermediate TRs and LAN rooms due to distance constrains along the way (cascading bottlenecks), then give singlemode a closer look. You may also want to give IEEE 10GE PON (ratified last year) some consideration, or <forsooth!> the ITU emerging variant of 10GPON for your desktop and lab areas, fwiw. BR, Frank --- jeff-kell@utc.edu wrote: From: Jeff Kell <jeff-kell@utc.edu> To: nanog@nanog.org Subject: Inside plant 10G fiber specs? Date: Sun, 14 Mar 2010 14:16:53 -0400 I am working up network specs for a new building, and trying to accomodate a 10G distribution from the start. The safe bet of running singlemode everywhere doesn't quite fit due to cost of the optics and the need for multimode for some other (non-network) devices anyway. We have a legacy 62.5u/MM campus, inside and out. The 100M to 1G transition led to some outside plant singlemode additions due to length restrictions on MM (even with conditioned LH optics), but the inside plant gig was fine with multimode (typically SH optics). 10G appears to break the inside 62.5u/MM fit, with the addition that there is no option of "LH over MM" for the little extra push beyond the SH limit that worked with 1G optics. Cisco's references give 10G SH over 62.5u/MM at 26m or 33m, depending on the "modal bandwidth" of the fiber. At those distances it is of little benefit except some limited vertical risers. 10G over 50u/MM looks better, depending on the "modal bandwidth" of the fiber (66m, 82m, 300m). So, a couple of questions... (1) Do you have a good vendor specification (or sample cables) for multistrand 50u/MM suitable for the 2000Mhz/km (300m) advertised reach? (2) Inter-operability issues with legacy equipment where we have always used 62.5? We have at least two alarm half-duplex loops over 62.5 that will have to "mate" with devices in this building... if I can avoid running both types MM that would be great. (3) Any other considerations or words of advice would be welcomed. Thanks in advance. Jeff