Troubleshooting guide

7
Special Considerations
Frame Relay NNI Interface Limited
Although limited functionality for a frame relay NNI interface is present in the Release 2.0.9
software, this is not a supported functionality.
Internal Looping of Frame Relay UNI Port
Looping of a Frame Relay UNI interface provides no useful diagnostic information because the UNI
protocol is asymmetric. The LightStream 2020 switch supports internal looping of such a port by
first converting it to an NNI interface. A successful loop sets the administrative state of the port to
testing and the operational state to up.
Looping of FDDI and Ethernet Ports Not Supported
In Release 2.0.9, FDDI and Ethernet ports cannot be looped.
No Error Checking with setsnmp
The CLI utility allows you to directly modify variables in the MIB using the setsnmp command.
This command performs no validation of its input data and does not prevent you from setting a MIB
variable to an inappropriate value.
Workaround: Use the following command within the CLI to change MIB variables:
set <object-type> [object-id] [parameter1 ... ]
This approach gives the CLI enough context to validate the new value for the variable before
performing the change to the MIB.
Modifying the PLC/Ethernet Access Card POST
The POST timeout value on all packet line cards and cell line cards (PLC and CLC) must be
modified to support new PLC and CLC POST.
Verify the POST timeout value of cards in your system by typing the following at the TCS command
prompt:
read slot ee 44 word
The value read should be 0x0e4e.
If the value read is different from this one, enter the following at the TCS command prompt:
write slot ee 44 e4e word
Support for Synchronous Digital Hierarchy
The oc3InfoMediumType object can be set to 1 for Synchronous Optical Network (SONET)
operation or to 2 for Synchronous Digital Hierarchy (SDH) operation of the OC-3 card.
The default for OC-3 ports is to use SONET. The following paragraphs tell you how to set a series
of OC-3 ports to use SDH instead of SONET.