Information Technology Reference
In-Depth Information
Table6-1
Media Problems: Token Ring (continued)
Media Problem
Suggested Actions
Relay open in
MAU
1.
If an “open lobe fault” message appears on the console at
system power up, check the cable connection to the MAU.
2.
Use the
clear interface
privileged exec command to reset the
Token Ring interface and reinsert the router into the ring.
For all Token Ring cards except the CTR and access routers, you
must use the
clear interface
command to reinitialize the Token
Ring interface if the interface is down.
Use the
show interfaces token
exec command to verify that
the interface and line protocol are up.
3.
If the interface is operational, but the “open lobe fault” message
persists and the router still cannot connect to the ring, connect
the router to a different MAU port.
4.
If the message continues to appear, disconnect all devices from
the MAU and reset the MAU's relay with the tool provided by
the MAU vendor.
5.
Reattach the router and determine whether it can connect to the
ring. If resetting the relay does not solve the problem, try
replacing the MAU with one that is known to be operational.
6.
If the router still cannot connect to the ring, check internal
cable connections of the router Token Ring cards. Ensure that
cables associated with the respective port numbers are correctly
wired and that they are not swapped.
7.
If the router still cannot connect to the ring, replace the cables
that connect the router to the MAU with working cables.
8.
Use the
clear interface
command to reset the interface and
reinsert the router into the ring. Use the
show interfaces token
command to verify that the interface and line protocol are up.
9.
Alternatively, you can connect the router to a spare MAU to
which no stations are connected. If the router can attach to the
ring, replace the original MAU.
10.
Duplicate
MAC
2
address
This problem can arise when routers are using locally administered
MAC addresses.
1.
Use a network analyzer to check the Duplicate Address test
frames from a booting station. If the station gets a response,
then there is another station already configured with the MAC
address of the booting station.
2.
If there are two stations with the same MAC addresses, change
the MAC address of one of the stations and reinitialize the
node.
