Issue link: http://www.epageflip.net/i/1043933
40 I ICT TODAY Distance limits for 10 GbE/s over OM4 and OM5 are listed at 400 m in Figure 2. This limit is set by TIA and IEEE standards based on worse case assumptions. However, these distances can likely extend out to 500 or 550 m. The 400 meter limit is based on the transceiver having a spectral width of 0.65 nm, but most of these transceivers today are 0.47 nm, so the distance can typically extend farther than 400 m. That is a conversation to have with the cabling manufacturer. • 40 and 100 GbE/s When considering multimode for 40 Gigabit Ethernet—namely 40GBASE-SR4 using four transmitters and four receivers—an MPO-style connector is needed. Older OM1 or OM2 fiber cannot be used to support 40 and 100 GbE/s. Also, the distance limits will drop to 100 m for OM3 and 150 m for OM4/OM5. The original intent of 40GBASE-SR4 was for the data center where the vast majority of the links are less than 100 m. In contrast, enterprise links are typically much longer than 100 m. These networks will likely deploy 10GBASE-SR throughout the campus, and then 40GBASE-SR4 in server rooms or telecommuni- cations rooms. Moving to 100GBASE-SR4 reduces the supported length further to 70 m over OM3 and 100 m over OM4/OM5, which is why there is an increase in the deployment of OM4 fiber and the growing consideration of singlemode, which is not so distance limited. There are two IEEE Ethernet compliant options for 100 GbE/s over multimode: 100GBASE-SR10 and 100GBASE-SR4. The 100GBASE-SR10 standard was introduced in 2010 and delivers 100 GbE/s over 10 lanes at 10 GbE/s per lane, requiring 20 fibers in total and the use of a 24 fiber MPO connector. With most installations at the time utilizing 12 fiber MPO connectors, its adoption was not nearly as successful as 100GBASE-SR4, introduced in 2015. 100GBASE-SR4 reduced the lane count to four lanes at 25 GbE/s each, requiring only eight fibers in total, supported over the existing 12 fiber MPO installations. FIGURE 3: MPO lane assignments for 40 and 100 GbE/s. MTP ® is a registered trademark of USConec Ltd.