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| Title: | FDDI - The Next Generation |
|
| Moderator: | NETCAD::STEFANI |
|
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
580.0. "Debug at Frame level ?" by WELLIN::MCCALLUM () Thu May 21 1992 08:22
I have a customer doing some FDDI developments. I'm a bit naive about FDDI ,
How do you debug at this level ?
Can anyone help with what I should recommenmd to this guy or hwat the problem
might be???
Thanks,
Dave McCallum
--------------
Hi Dave
Hope all is well at Welwyn.
We recently received the DECconcentrator that we were dicussing in February
and are putting it now through its paces. We have come across something
peculiar and I invite your comments on it:-
We are currently performing tests on a small FDDI network consisting of ...
1. An AMD FASTcard
2. Our own station, based on the SUPERNET2 chipset
3. A DECconcentrator 500.
If the FASTcard is connected directly to our own station the MAC frame
count is, as expected, around 10 frames per second.
With all 3 stations connected to the network it is observed that the MAC
frame counters, on both our card and the FASTcard, rapidly increment. The
counting rate is in the order of 1 million frames per second. We feel it is
not due to real frame reception.
We think that the concentrator is generating fragments which the other
stations are interpreting as valid frames. Is this a correct assessment of
the situation and should it happen at all?
Best regards
Stelios
--
Stelios Pavlides Phone : +44 442 230000 ext 3468
Crosfield Electronics Ltd Fax : +44 442 232301
Hemel Hempstead, Herts. HP2 7RH, UK E-mail : [email protected]
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| T.R | Title | User | Personal
Name | Date | Lines |
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| 580.1 | | KONING::KONING | Paul Koning, A-13683 | Thu May 21 1992 10:49 | 10 |
| Fragments wouldn't show up in frame count (since a fragment isn't a frame).
Nor does the concentrator generate them, except as part of scrub during
station insertion.
What they are seeing are the void frames used by the ring purger. This is
harmless, but if it confuses them they can turn it off. Note that use of
the ring purger is strongly recommended for "real" networks since it cleans
up potentially troublesome junk left behind by various other implementations.
paul
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