Notes:
10BASE2 is designed as a smaller and less expensive alternative to 10BASE5, and is sometimes referred to as Thinnet or Thin Ethernet because of the much smaller cables. 10BASE2 is also a bus topology, but each of the workstations use a 'T' BNC connector to connect workstations to the central bus. Maximum segment length: 200 meters Maximum number of segments connected with repeaters: 5 (1000 meters) Maximum attachments per segment: 30 Minimum separation between attachments: .5 meters 10BaseF depends on the signaling technology and medium used but can go up to 2KM.
10Base2 (thin Ethernet or Cheapernet) is the least expensive way to cable an Ethernet network. However, the price difference between 10Base2 and 10BaseT (Ethernet over UTP) is rapidly diminishing. Still, for small, budget-conscious installations, 10Base2 is the most economical topology. The disadvantages of 10Base2 is that any break in the cable or poor connection will bring the entire network down, and you need repeaters if you have more than 30 devices connected to the network or the cable length exceeds 185 meters (607 feet).
10BaseT generally accepted to have a maximum run of 100-150M, but is really based on signal loss in Db's (11.5db maximum loss source to destination). 10BaseT is the most flexible topology for LANs, and is generally the best choice for most network installations. 10BaseT hubs, or multi-hub concentrators, are typically installed in a central location to the user community, and inexpensive UTP cabling is run to each network device (which may be 100m, or 330ft, from the hub). The signalling technology is very reliable, even in somewhat noisy environments, and 10BaseT hubs will usually detect many network error conditions and automatically shut-down the offending port(s) without affecting the rest of the network (unless, of course, the offending port was your server, shared printer, or router to the rest of the world). While the hardware is more expensive than 10Base2, the cabling is cheaper and requires less skill to install, making 10BaseT installation costs only slightly higher than 10Base2. The flexibility and reliability more than offset the marginally higher price.
10BaseF, and its predecessor, FOIRL, are the only recommended topologies for inter-building links. However, they need not be limited to this role. 10BaseF can also be run to the desktop, though the cost is prohibitively high in all but the most specialized environments (generally, extremely noisy manufacturing facilities, or very security-conscious installations). More commonly, FOIRL (and now, 10BaseF) is used inside buildings to form backbone networks and to connect wiring closets together.
The propagation speed of a medium refers to the speed that the data travels through that medium. Propagation delays differ between mediums, which affect the maximum possible length of the Ethernet topology running on that medium. In the following table, c refers to the speed of light in a vacuum, or 300,000 kilometers per second.
Medium Propagation Speed ------ -----------------
Thick Coax .77c (231,000 km/sec)
Thin Coax .65c (195,000 km/sec)
Twisted Pair .59c (177,000 km/sec)
Fiber .66c (198,000 km/sec)
AUI Cable .65c (195,000 km/sec)