System information

Troubleshooting IBM
Book Title
10-238
Router not sending
test frames to FEP
1
Step 1 With the debug sdllc and debug llc2 packet privileged exec commands enabled
on the router, check whether the router is sending test frames to the FEP.
Caution: Because debugging output is assigned high priority in the CPU process,
it can render the system unusable. For this reason, use debug commands only to
troubleshoot specific problems or during troubleshooting sessions with Cisco
technical support staff. Moreover, it is best to use debug commands during
periods of lower network traffic and fewer users. Debugging during these periods
decreases the likelihood that increased debug command processing overhead will
affect system use.
Step 2 If the router is sending test frames to the FEP, proceed to the next problem in this
table.
Step 3 If the router is not sending test frames to the FEP, use the show running-config
privileged EXEC command to view the router configuration. Make sure that the
sdllc partner interface configuration command is present.
Step 4 If the sdlc partner command is not present, add it to the configuration. Make sure
that it points to the hardware address of the FEP on the Token Ring. The following
is the syntax for the sdlc partner command:
sdlc partner mac-address sdlc-address
Syntax Description:
• mac-address— 48-bit MAC address of the Token Ring host.
• sdlc-address—SDLC address of the serial device that will communicate with
the Token Ring host. The valid range is 1 to FE.
FEP on Token Ring not
replying to test frames
Step 1 With the debug sdllc and debug llc2 packet privileged exec commands enabled
on the router, check whether the FEP is replying to test frames sent by the router.
Caution: Because debugging output is assigned high priority in the CPU process,
it can render the system unusable. For this reason, use debug commands only to
troubleshoot specific problems or during troubleshooting sessions with Cisco
technical support staff. Moreover, it is best to use debug commands during
periods of lower network traffic and fewer users. Debugging during these periods
decreases the likelihood that increased debug command processing overhead will
affect system use.
Step 2 If the FEP is responding, proceed to the next problem in this table.
Step 3 If the FEP is not responding, check the MAC address of the router’s partner (the
FEP). Make sure that the address is correctly specified in the sdllc partner
command entry on the router. The following is the syntax of the sdlc partner
command:
sdlc partner mac-address sdlc-address
Syntax Description:
• mac-address—48-bit MAC address of the Token Ring host.
• sdlc-address—SDLC address of the serial device that will communicate with
the Token Ring host. The valid range is 1 to FE.
Step 4 Check whether RSRB peers are up. If the peers are not open, refer to the section
“RSRB: Host Cannot Connect to Server (Peers Not Open)” earlier in this chapter.
Step 5 If the RSRB peers are up, attach a network analyzer to the Token Ring with the
FEP attached and make sure that the router’s test frames are arriving on the ring
and that the FEP is replying.
Possible Problem Solution