: New modems are problematic.
The 96 new modems purchased for the Springfield off-campus dial-up modem pool are
causing failed connections, unsolicited disconnects, and poor connection rates.
All users are potentially affected. Those users with exceptional quality
telephone lines will probably not have any problems.
May 6, 1999
The four month saga is finished!!! All modem problems have
been fixed by ditching the MICA modems!!! Well, at lease we think its
finished. Cisco came through with their promise to "make us whole".
They have "given" us another AS5300 communications server with 48 Microcom
modems on permanent loan. They also have taken back the 96 MICA modems and replaced
them with 48 more Microcom modems. The net result is that we now have 230 good
Microcom modems serving our dial-up pool and all of the dubious quality MICA modems have
been returned to Cisco.
As many will recall, the MICA modems have caused us lots of problems such as poor
connections rates, unsolicited disconnects, and just plain failures to connect. Most
users should see a very noticeable improvement in our modem pool stability and reliability
now that all MICA modems have been removed from all dial-up pools.
April 8, 1999
As planned, we attempted to replace the 96 MICA modems with 48 Microcom modems and a
loaner AS5200 chassis of 48 additional Microcom modems. Unfortunately the
replacement equipment was unsuitable and the change was backed off. The trunk reorganization part has been
delayed until April 21, 1999 and further updates to this process will only be documented
in that news item. We do not yet have a time frame for replacing the MICA modems but
a new AS5300 with 48 Microcom modems is currently on order.
March 30, 1999
Cisco Systems has decided to replace the poorly-functioning MICA modems with Microcom
modems: the same modems that we have in the rest of our modem pool. These modems,
however, take twice the physical space and another chassis will be added to support them.
Until our new AS5300 chassis arrives, Cisco has loaned us an AS5200 and all
Microcom modems are in house. Unfortunately, we are still waiting for memory to
arrive before the change out can be accomplished.
Other, non-related problems have been plaguing the modem pool as well from Missouri State University and
SWBT equipment failures to SWBT line and call-routing failures. The end result is
that some trunks have not been in service and some users have been getting dropped for
"unknown" reasons.
To help this, we will also be reorganizing all SWBT trunks for two reasons: 1) to
make the configuration simpler and hopefully more reliable; and 2) to implement NFAS.
NFAS will combine every two PRI lines into a single trunk using one D-channel and
23 + 24 B-channels. The net result will be a gain of 5 modems for the off-campus
Springfield modem pool. A minimum of a
two-hour outage is expected and is scheduled
for 8:00 a.m. on 4-7-99. Another
news item specifically covering this outage will be added as soon as possible.
February 9, 1999
Since January 6, 1999, we have had a case of trouble open with Cisco regarding modem
drops, lower connect speeds, and failure to connect at all. The problem was
initially opened due to our staff and a friend reporting poor connection rates.
Although we have heard rumors of drops and failures to connect, only one person has
contacted us regarding a problem. We, therefore, felt the problems were minimal, but
pursued them none the less.
We discovered late yesterday that Cisco Systems dropped near-end echo cancellation from
the MICA modems early in the design phase. This causes failed connections, poor V.34
or lower connection rates, and call disconnects for no apparent reason on trunks that have
a "high" amount of near-end echo. At least one view is that this is a
trunk problem and we should have it re-engineered from SWBT. Although we are talking
with SWBT regarding this issue, we do not currently take this view. This is because
many people, according to the modem statistics, are actually connecting just fine.
We do, however, have documented cases where users worked fine before, but have severe
problems now.
We are now actively working with Cisco to see if they can fix this problem in a timely
fashion and, if not, Cisco has committed to resolving the issue in any way possible.
We are investigating trading out the MICA modems for Microcom modems which include
the near-end echo cancellation feature. Please keep checking back here for current
status information regarding this problem. Those with
CCO access may check out bug
report CSCdk12436 for more details on the MICA modem problem. This bug
report has been reproduced here for your convenience.
