cch@sei.cmu.edu (Clifford Huff) (11/18/88)
Regarding the questions about LocalTalk on shielded twisted pair and a seperate question on large passive nets. At the Software Engineering Institute, we have had some experience with large Passive Star Topologies on shielded wiring. We have a single building that is wired for both IBM Type 1 cabling (combination of data and voice shielded twisted pairs) and DEC Connect Thin-Wire Ethernet. We use the IBM cabling to run our AppleTalk networks. We very recently changed over to using FarallonUs Star Controllers on every node. Prior to this we had up to 25 nodes/branches successfully operating. AppleTalk network performance was affected by such a large passive net due to increased lost packets, but it did work. Once you reach a critical point in the size of the passive net, an additional passive node will generally make the net unusable. We did terminate each branch. If we had an unterminated branch, the general network performance would be very poor and some users would be unable operate at all. In cases where the passive net grew too large, we split the network in two with a Hayes InterBridge. We were very surprise to see how large we could make a passive star network, especially on shielded twisted pair with its greater line loss. In the long run you are certainly better off with an active Star Controller hub. We have certainly seen a improvement in overall thoughput since installing the Star Controllers. We originally installed our first Star Controllers using their RJ-11 Harmonica Blocks and later switched to their new 19-inch Rack Mounted Patch Panels. The Rack Mounted Panels are very nice since they support four branches on a single Star Controller port. ____ ______ _____ _____===== Cliff Huff / __ \ | _____| |_ _| _____========= cch@sei.cmu.edu | |__|_| | |__ | | _____============= Software Eng. Institue _\___ \ | __| | | _____================= Carnegie-Mellon Univ. | |__| | | |____ _| |_ _____============= Pittsburgh, PA 15213 \____/ |______| |_____| _____========= (412) 268-7605 -----===== C a r n e g i e - M e l l o n U n i v e r s i t y _____________________________________________________________________________ Disclaimer: The views contained herein are my own, not those of my employer. _____________________________________________________________________________