xdaa374@ut-emx.UUCP (William T. Douglass) (09/22/88)
We are having a very bad time trying to fix noise (or echo or whatever)
problems on our PhoneNet-based AppleTalk network. Configuration is -
22 Mac Nodes
1 NEC SilentWriter PostScript printer
2 AppleTalk ImageWriter Printers
~ 2000 ft of 22 gauge phone wire, all nodes using PhoneNet
or similar network connectors.
One or two nodes on the net will lose sight of the printer at times. Often,
unplugging a machine from the backbone truck will cause another machine
to lose contact w/ the printer. Outage occurs through the network, with
no rhyme or reason. Right now, the machine closest to the printer (next
to it, in fact) cannot find the plasted thing!
Help. 1) Does anyone have any familiarity with sich problems
2) What network analysis tools can you recommend for such a
problem? Any hardware/software analysis products would be welcome.
I have Seer & NetCheck. OI also have a copy of MacEcho from Simtel20, but it
refuses to run. Any help w/ this program would be appreciated also.
Thanks for any & all help. Mail or post replies, but be aware that this
system seems to have some problems receiving mail (or has in the past.)
--
Bill Douglass, TCADA
"I dreamed I was to take a test,
in a Dairy Queen, on another planet." L. Andersonevan@SSYX.UCSC.EDU (Evan Schaffer) (09/22/88)
farallone star cluster controllers will help a lot. you should also try tops repeaters. if you have wired your phonenet according to the manual you should be able to test the physical medium with an ohmmeter at every node, locating the noisy segment and repairing or replacing it. this is not a black art.
bruce@voysys.UUCP (Bruce Beare) (09/24/88)
In article <6226@ut-emx.UUCP>, xdaa374@ut-emx.UUCP (William T. Douglass) writes: > We are having a very bad time trying to fix noise (or echo or whatever) > problems on our PhoneNet-based AppleTalk network. Configuration is - > 22 Mac Nodes > 1 NEC SilentWriter PostScript printer > 2 AppleTalk ImageWriter Printers > ~ 2000 ft of 22 gauge phone wire, all nodes using PhoneNet > or similar network connectors. > ... > Bill Douglass, TCADA We have around 50 Macs on two networks, all connected with Phone Net. Initially, we tried to do it with straight wiring, but quickly found it impossible to get a stable network. We purchased two Star Controllers & all problem went away. Bruce Beare Voysys Corporation ..!pyramid!ctnews!voysys!bruce
wnn@DSUNX1.DSRD.ORNL.GOV (W. N. Naegeli) (09/27/88)
The Tops Repeater will not help you with noise. It is only useful in situations where signal strength is insufficient to be picked up by all nodes on a network with a large effective length. The repeater is simply an amplifier and as such, it unfortunately also amplifies noise. If noise is really your problem you may be worse off with a Tops Repeater. By contrast, the Farallon StarController does not merely amplify the signal but has its own receivers and transmitters and reconstitutes the signal. It will effectively deal with both noise and weak signals, but its cost is fairly steep if you need only two of its twelve ports. I understand that the Farallon NetRelay that has recently been announced with a list price of $500, but is not yet shipping, if I am right, essentially is a similar solution but has only two (or three?) ports and cannot be controlled through network management software like the StarController. It may just be what you need. An ohmmeter can reveal the grossest of network problems, but it cannot detect noise or reflections. With the ohmmeter you can test for continuity and whether network resistance is in the tolerable range. With a Voltmeter you can also test for shorting to other (telephone) circuits and induced currents (both AC and DC measurements should be zero when all devices are disconnected from the net). To detect and pinpoint noise and reflections however, you need more advanced instruments, such as storage scopes with high resolution for timing signals and reflections.