Cabletron Systems BRIM-E100 Manual De Usuario

Descargar
Página de 42
Multimode Specifications for the FE-100FX
BRIM-E100 User’s Guide
Page 2-3
2.2 MULTIMODE SPECIFICATIONS FOR THE FE-100FX
The BRIM-E100 supports the Cabletron Systems FE-100FX. The 
FE-100FX meets IEEE 802.3u standards. When connecting a fiber optic 
segment to the BRIM-E100 with the FE-100FX module installed, the 
network must meet the following requirements:
Cable Loss
Test the fiber optic cable with a fiber optic attenuation test set adjusted for 
an 850 nanometer (nm) wavelength. This test verifies that the signal loss 
in a cable is within an acceptable level. The maximum loss for a 
multimode fiber optic cable is 11.0 decibels (dB).
Fiber Optic Budget and Propagation Delay 
Determine the maximum fiber optic cable length by calculating the fiber 
optic budget delay and total network propagation before fiber optic cable 
runs are incorporated in any network design.
Fiber optic budget is the combination of the optical loss due to the fiber 
optic cable, in-line splices, and fiber optic connectors.
Propagation delay (collision delay) is the amount of time it takes data to 
travel from the sending device to the receiving device. Total propagation 
delay allowed for the entire network is 256 bit times (2.56 
µ
s). If the total 
propagation delay between any two nodes on the network exceeds
2.56 
µ
s, then further segmentation of the network through the use of 
bridges or other devices is required.
2.3 NETWORK CABLE LENGTHS
This section details the maximum network cable lengths specified by the 
IEEE 802.3u standard. As stated in the previous sections, the physical size 
of the network is limited primarily by propagation delay. The propagation 
delay cannot exceed 256 bit times.
A 100BASE-TX/FX network might use all copper (UTP) links, all fiber 
links or a combination of both. The maximum length of any segment is 
determined by the types and combination of links and by the type of 
repeater (if any) between segments. IEEE 802.3u standards specify two 
repeater classes (Class 1 and Class 2) and the maximum cable lengths for 
each media type.
book  Page 3  Friday, April 19, 1996  9:53 AM