QWYELX@HUMBER.BITNET (Erone Quek) (08/30/89)
We have a problem in our local area network and any help will be more than appreciated. Background: - physical installation - IEEE 802.3 over twisted pair/fiber optics, star configuration - Synoptics Lattisnet Model 1000 premise concentrators - fiber optics between concentrators - unshield twisted pair (UTP) (4-pair) from concentrator to user access RJ45 jack - protocol & applications - tcp/ip only - telnet, ftp, smtp, sun-nfs, tn3270 - legend === --- *** +++ || | * + || fiber | UTP * AUI cable + thin wire ethernet 505s -- Synoptics AUI/UTP Transceiver (Xcvr) - topology -------------------- -------------------- |Lattisnet mod 1000 | |Lattisnet mod 1000 | |central concentrator| |local concentator 1 | |204 Retiming card | |405 UTP host modules|-------------------- |201-ST Interconnect | ====|203-ST fiber termin.| | -------------------- -------------------- | || || | || || PC 1, MS-DOS, PC/TCP v2.03, WD8003E-TP --| || || | || || SUN 1, SUN 3/280, SUN OS 4.2********505--| || || | || || IBM3090, MVS, ACC9315, ACCES/MVS****505--| || || | || || Bridge CS/1 term server*************505--| || || || || -------------------- || || |Lattisnet mod 1000 | || || |local concentator 2 | || || |405 UTP host modules|-------------------- || ======|203-ST fiber termin.| | || --------------------- | || | || ISI 1, ISI V24/68020, BSD 4.3*******505--| || || -------------------- || |Lattisnet mod 1000 | || |local concentator 3 | || |405 UTP host modules|-------------------- ============|203-ST fiber termin.| | --------------------- | | SUN 2, SUN 3/280, SUN OS 4.2********505--| | ------------------ | |DEC DEMPR |****505--| +++++++++++++++++++++++++++++++++++++|thin wire repeater| + ------------------ + +++++ --------- |DEC DESTA|*****ISI 2, ISI V24/68020, BSD 4.3 --------- -all cable/fiber lengths are within Synoptic's spec. Okay, with this topology : What works: - PC 1 can talk to every one - SUN 1 can talk to every one - IBM3090 can talk to every one - CS/1 can talk to every one EXCEPT ISI 2, can't connect to it - ISI 1 can talk to every one (identical hardware as ISI 2) - SUN 2 can talk to every one - ISI 2 can, with difficulty, talk to every one EXCEPT the CS/1 - what difficulty ? - when I do a netstat -I ex0 Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Collis ex0 1500 xxx.yy isi2 424082 0 325703 0 208550 - although this works, it's not at all desirable. As you can see, I can, theoretically, plug the AUI cable from ISI 2 into a 505 and straight to the Synoptics box, and that's what is NOT working. If I took the DEMPR out, as soon as I plug the 505 (which has ISI 2 on the other end) onto the Synoptics concentrator, I got a constant collision signal on the concentrator and the whole network was jammed. However, netstat -I ex0 on ISI 2 will NOT show any significant collisions !! I swapped 4 ethernet boards off ISI 2, same results. My questions, finally: What's going on ? What did I do wrong ? Incompatibilities at where ? Thanx in advance Erone Quek