ITWissen.info - Tech know how online

fiber optic inter repeater link (Ethernet) (FOIRL)

Repeaters and remote repe aters are used as network components for the topology extension ofEthernet beyond a LAN segment. Remote repeaters consist of two repeater units that are implemented as a point-to-point connection via a link segment. The optical link segment between the two halves of a remote repeater is standardized in FOIRL (Fiber Optic Inter Repeater Link).

The FOIRL interface operates at a typical wavelength of 850 nm over duplexoptical fibers. The standard provides for gradient fibers with 50/125 µm, 62.5/125 µm, 85/125 µm and 100/140 µm. In Germany, the 50/125 µm fiber is predominantly used. The attenuation of the optical link segment should not exceed 7 dB, and the cumulative delay time of all optical link segments from one path between two Ethernet stations must not exceed 5.14 µs. For an 850 nm source, the standard provides for a bandwidth of more than 150 MHz for a 1-km link.

Structure of a FOIRL

Structure of a FOIRL

FOIRL uses FSMA as the connector type with an attenuation of less than 2.5 dB. The permissible distance for the optical link segment depends on the number of LAN segments and repeaters. If the transmission path consists of five LAN segments and four repeaters, and two link segments are used, then the permissible distance per link segment is 500 m. If four LAN segments and three repeaters are used, the FOIRL segments can be 1000 m long.

Due to the unidirectional transmission characteristics of optical fibers, an optical link segment consists of two fibers, one in each direction.

By simultaneously using the second optical window at 1,350 nm, FOIRL would be possible with only one optical fiber between the two repeater halves.

Informations:
Englisch: fiber optic inter repeater link (Ethernet) - FOIRL
Updated at: 22.07.2003
#Words: 260
Links: remote, network, topology, extension (EXTN), LAN segment
Translations: DE
Sharing:    

All rights reserved DATACOM Buchverlag GmbH © 2024