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This soft copy for use by IBM employees only.
Memory dump for error log sector aborts with a system error before it
completes. Memory dump should be done only at the request of product
support. In most cases the partially received dump file contains enough
information for analysis.
2.4 User filter clarification.
- ATM bridge supports only inbound filters.
- In Token Ring mode ATM bridge applies filters only on broadcast frames.
- In Ethernet mode ATM bridge applies filters on every frame.
- ATM bridge performs the following computation to determine whether
to apply a user filter: if (frame and filter_mask) equal filter_value then
apply filter.
2.5 How to connect to the bridge using a modem.
The following paragraphs explain how to configure telephone modems
and TCP/IP software to enable communications via telephone lines.
The ATM bridge configurator program can be used via telephone modems.
The only modem command issued by ATM bridge is ATE0 to turn echo off.
The modem must be configured before it is attached to the bridge. We
tested several modems, and found that the following configuration works
well for Hayes compatible modems:
AT &F - Restore to factory setting.
AT &K0 - Disable flow control.
AT &D0 - Allow phone connection to stay up when bridge
resets.
AT S0=2 - Auto-Answer on second ring.
AT &W - Save configuration.
Since ATM bridge communicates via TCP/IP, the SLIP protocol must
be configured to dial remote modem. The dial string must be set to
ATDTXXXXXXXX where ″XXXXXXXX″ is the telephone number, and the ″Auto-Dial″
option must be enabled. For some reason not enabling Auto-Dial option
and using SLIPDIAL after TCP/IP is started does not work.
Once connection is established between modems, ping the bridge at
1.2.3.5 to verify connectivity. We noticed that it may take up to
30 seconds for some modems to forward pings successfully. The delay is
probably due to auto learning of DTE speed between modem and ATM bridge.
The bridge communicates on it′ s serial port at 19200, 8 data, 1 stop,
no parity.
To insure that your modem is compatible with the bridge, reset the
bridge while modem is attached and powered on, but does not have phone
connection. After the bridge resets verify that you can dial in and
ping the bridge. One modem we tested, Motorola Codex 3260, did not pass this
test. The problem was most likely caused by ATM bridge sending various
messages out the serial port while it is resetting.
2.6 Problem: Configurator communication errors when Max Frame Size
is reduced below 1500 bytes.
Release 1 versions of the bridge and Configurator would allow IP frames
as large as 1518 bytes. If the bridge′ s ″Max Frame Size″ is set lower than this
the 8281 bridge will throw away the IP frames (and subsequent retries) to
and from the configurator. Thus the configurator and bridge could not complete
Profile sends or retrievals successfully. Release 2 of the 8281 and configurator
should work with ″Max Frame Size″ set to 1112 bytes or higher. If there is a
192 ATM Workgroup Solutions: Implementing the 8285 ATM Switch