Cabletron Systems BRIM E100 BRIM-E100 User Manual

Multimode Specifications for the FE-100FXBRIM-E100 User’s GuidePage 2-32.2 MULTIMODE SPECIFICATIONS FOR THE FE-100FXThe BRIM-E100 supports the Cabletron Systems FE-100FX. TheFE-100FX meets IEEE 802.3u standards. When connecting a fiber opticsegment to the BRIM-E100 with the FE-100FX module installed, thenetwork must meet the following requirements:Cable LossTest the fiber optic cable with a fiber optic attenuation test set adjusted foran 850 nanometer (nm) wavelength. This test verifies that the signal lossin a cable is within an acceptable level. The maximum loss for amultimode fiber optic cable is 11.0 decibels (dB).Fiber Optic Budget and Propagation DelayDetermine the maximum fiber optic cable length by calculating the fiberoptic budget delay and total network propagation before fiber optic cableruns are incorporated in any network design.Fiber optic budget is the combination of the optical loss due to the fiberoptic cable, in-line splices, and fiber optic connectors.Propagation delay (collision delay) is the amount of time it takes data totravel from the sending device to the receiving device. Total propagationdelay allowed for the entire network is 256 bit times (2.56 μs). If the totalpropagation delay between any two nodes on the network exceeds2.56 μs, then further segmentation of the network through the use ofbridges or other devices is required.2.3 NETWORK CABLE LENGTHSThis section details the maximum network cable lengths specified by theIEEE 802.3u standard. As stated in the previous sections, the physical sizeof the network is limited primarily by propagation delay. The propagationdelay cannot exceed 256 bit times.A 100BASE-TX/FX network might use all copper (UTP) links, all fiberlinks or a combination of both. The maximum length of any segment isdetermined by the types and combination of links and by the type ofrepeater (if any) between segments. IEEE 802.3u standards specify tworepeater classes (Class 1 and Class 2) and the maximum cable lengths foreach media type.