dwg@bpdsun1.uucp (David W. Glessner) (09/11/89)
In the last month, we have had two cases where failed transceivers held our ethernet high. Both failures occurred during thunderstorms. (The rain is great for the local farmers, but we can do without the lightning :-) The network has been installed for about 1.5 years. There weren't any failures last summer. There weren't any big thunderstorms either. We use non-intrusive Excelan and Isolan Lanview transceivers. Our 500 meter thick ethernet coax goes from one end of "building A" to the other end of "building B". The midpoint of the coax is solidly grounded (shield connected to a copper bar pounded into the ground) near the entrance to building A. Between the two buildings (about 150 ft), the coax is housed in a buried PVC tube. What should we do to avoid future failures? Is our coax properly grounded? If the failures are caused by ground potential differences between the two buildings, would inserting a fiber optic interface in the middle of the coax help? Should we install fiber in the PVC tube, or is simply separating the coax sufficient? -- David <whatever>NET: quintro!bpdsun1!dwg@lll-winken.llnl.gov uunet!tiamat!quintro!bpdsun1!dwg
hedrick@geneva.rutgers.edu (Charles Hedrick) (09/13/89)
We do not recommend running copper of any kind between buildings. You can sometimes get away with it, but it's asking for trouble. Rather than running ethernet coax, you should use fiber. The most straightforward approach is probably to use a fiber remote repeater. This is two halves of a repeater connected by fiber. The fiber can be up to 1 km, if I recall the Ethernet configuration rules. If you have a PVC tube, it might not be too much work to replace the coax with fiber. You can get remote repeaters from DEC and a number of other vendors of Ethernet hardware.