QWYELX@HUMBER.BITNET (Erone Quek) (08/29/89)
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 ?
Erone Quek