Information Technology Reference
In-Depth Information
networking technology you are trying to support. For example, certain fiber runs
may be limited to 220 m for Gigabit Ethernet, so you would want to stay under that
length. However, with the right multimode fiber, you can use two new standards,
10GBaseSR and 10GBaseLX4, to support 10 Gigabit Ethernet to 300 m. With sin-
gle-mode fiber, though, you can get up to 10 km using the 10GBaseLR standard.
If centralized fiber does have one limitation, it is the ability to handle future increases
in network bandwidth. Remember that the current crop of legacy fiber in the horizontal
cabling is miraculously able to support gigabit because of the short horizontal limit of
structured cabling. Newer laser-friendly multimode and single-mode cable is still an
overkill at 90 m for gigabit, but it might be just right at 10 Gb operation. A measure of
future-proofing can be obtained by at least running your centralized fiber through a TR.
Then, if you absolutely must have shorter fiber runs to support a future technology, you
can cut and terminate the fiber runs within the TR and place your hub equipment there.
Standard Fiber-Optic Network Links
Fiber is used for a wide variety of network connections. Many of these are described
elsewhere in this topic, including Chapters 6 and 12. However, some of this infor-
mation is repeated in Table 11.5 to illustrate the wide variety of purposes to which
fiber-optic cabling can effectively be utilized.
The networking equipment you use with structured fiber-optic cabling must be com-
patible with the installed fiber in order to function. You may need to use simple con-
TABLE 11.5
Fiber Optic Networking Standards
Standard Speed Media Distance
10BaseFL 10 Mbps Multimode 2000 m
100BaseFX 100 Mbps Multimode 400 m
100BaseSX 100 Mbps Multimode 300 m
ATM/OC-3 155 Mbps Single-mode N/A
ATM/OC-12 622 Mbps Single-mode N/A
1000BaseSX 1 Gbps Multimode 220-550 m*
1000BaseLX 1 Gbps Multimode/ 400-550 m*
single-mode 5 km
1000BaseSLX 1 Gbps Single-mode 10 km
*Distance for multimode fiber depends on the core/cladding size, bandwidth-distance product, and operating
wavelength.
