IBM 8285 Nways, Installation And User Manual

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Problems with IBM Proprietary LAN Emulation
This section details the problems that may occur during the setup of an IBM proprietary LAN emulation
environment. Such an environment may include concentrators (8282) and bridges (8281), an external
IBM LAN Emulation Server (LES), workstations (WS), ATM Workgroup Switches (workgroup switch), and
8260 hubs.
A workstation/bridge cannot connect to another workstation/bridge.
Steps to Take:
1. Using the LES monitor, check in the list of registered end stations that both workstation/bridge addresses are
present. If you do not know the ATM adresses of your workstation/bridge, use the ATMC Interface Configuration
panel for the ports attached to your workstation/bridge. If both addresses are registered in the LES, then proceed
to point 3.
2. If one workstation/bridge address is missing, then use the Call Status History provided by the LES monitor to get
the Q.2931 cause of the failing call. The missing station/bridge has probably a wrong LES ATM address defined in
its configuration. Check the missing station's configuration.
3. Both workstation/bridges are registered to the LES, but one cannot call the other one, because the LES is not
available any more (port disabled, or not-in-service). The LES does not tell you that it has lost its address,
because it only tells that once the connection to the switch is returned.
Check that the LES cable is well plugged, then check that the LES port is enabled. If it stays enabled and
not-in-service, then the LES is faulty. Contact your IBM service representative for investigation, or re-boot the LES.
LES Monitor Statistics: Default Vccs counter oscillating, too few registered workstations.
Explanation: The workstation knows its ATM address, but that address has been deregistered at the
Switch/Control-point level. This happens when the workstation is behind a concentrator (8282) that has been
disconnected from the switch for a short time.
Note: You can check whether the station is registered in the workgroup switch by using the command SHOW
ATM_ESI.
Steps to Take:
1. Wait a few minutes for the new registration to take place.
Workgroup Switch Clear Table: a lot of SVCs were cleared with Cause 31.
Explanation:
Ÿ A high-bandwidth (100Mbps or 155Mbps) workstation or bridge has tried to call a low-bandwidth workstation
(25.6Mbps). The call was rejected by the low-bandwidth workstation because the bandwidth specified in the
Q.2931 parameters (even for a UBR call) was too large. This is normal.
Ÿ The source or bridge retried to call the destination station with a lower bandwidth/bit-rate successfully.
Steps to Take:
1. No action required.
Chapter 21. Troubleshooting
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