System information

Troubleshooting IBM 10-231

SDLC: Router Cannot Communicate with SDLC Device

Symptom: Router cannot communicate with an IBM SDLC device.

Table 10-9 outlines the problems that might cause this symptom and describes solutions to those

problems.

Table 10-9 SDLC: Router Cannot Communicate with SDLC Device

Trying to bridge protocols that embed

the MAC address in the Information

ﬁeld of the MAC frame (such as IP

ARP, Novell IPX, or AARP)

If MAC addresses are embedded in the Information ﬁeld of the MAC frame,

bridges will be unable to read the address. Bridges will therefore be unable

to forward the trafﬁc.

Step 1 If you are attempting to bridge this type of protocol, route the

protocol instead.

Step 2 If you still cannot communicate over the router, contact your

technical support representative.

Media problem Verify the line using the show interfaces exec command. If the interface or

line protocol is down, troubleshoot the media. For LAN media, refer to the

chapter that covers your media type.

1 MTU = maximum transmission unit

Possible Problem Solution

Physical layer problem

Step 1 Use the show interfaces exec command to determine whether the

interface and line protocol are up.

Step 2 If the interface and line protocol are both up, troubleshoot link-layer

problems as described later in this table.

Step 3 If the output does not indicate up/up, make sure the device is powered

on. Make sure all cabling is correct, securely connected, and

undamaged. Make sure the cabling does not exceed the recommended

length for the speed of the connection.

Step 4 If the interface or line protocol is still down, use a breakout box to

check the signals on the line.

Possible Problem Solution