On Wed, Feb 2, 2011 at 10:40 AM, Holstrom, Don <[email protected]> wrote: > I work in an old Museum here in the District. My runs are very long, one is > over 700 feet and gives me a problem every now and then. Is it worthwhile to > switch out our CAT4&5 and go to CAT6a (there is something above 6a?)
As everyone else has said, twisted pair Ethernet is limited to 100 meters (~328 feet) in the spec. This is independent of speed -- anything from gigabit to ten megabit, CAT3 to CAT6A, the limit is 100 meters. Repeaters or switches along the way will let you extend that distance. I'd suggest switches; that keeps the path full-duplex and you don't have to worry about repeater hop limits. Fiber can go longer still. How long depends on the type and grade of fiber. Exact numbers seem to vary by manufacturer. HP (ProCurve) ranges from 220 meters (721 feet) on the cheapest to 70 kilometers (43 miles) on the high end. (http://tinyurl.com/4kdkoda) If you don't have existing modular ports (SFP) in your switches, you can get single-port media converters for small money. Installation is usually the pricey part. I've read nothing good about Ethernet-over-power-lines. The grade of UTP mainly determines maximum speed: CAT3 = 10 megabit CAT5 = 100 megabit CAT5E = 1 gigabit CAT6 = waste of money CAT6A = 10 gigabit The 100 meter limit comes about due to the time it takes for signal propagation in a copper medium. In the event of a collision detection, a "jam signal" is transmitted. There has to be enough time for the jam signal to reach all other nodes before the next transmission opportunity. Since it's a timing limit, on a full duplex point-to-point link (i.e., most links these days), you can actually go a longer distance and still have it sometimes sort-of work. However, you're out-of-spec, so anything can happen. It might fail on alternating Tuesdays, or it might cause demons to fly out of your nose. -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
