 
8260> show ring_map token_ring logical token_ring_1
Token Ring Logical Map for Network TOKEN_RING_1
MAC Address Slot Port
----------------- ----- ----
02-00-00-c0-cc-1c 05.01 1
02-00-00-c0-cc-0a 05.01 2
02-00-00-e0-9c-10 05.01 2
08-00-8f-40-01-a6 05.01 3
8260>
 
Figure 100. Address-to-Port Map Display for Fan-Out Attached Devices
There could be situations, where the two MAC addresses between which the
new station is inserted are on the same port. This could happen, for example,
when two stations are currently attached to a fan-out device′s ports 1 and 3 and
a third station inserts between them on port 2 of the fan-out device. In this case,
the Recovery ASIC concludes that the new station is on the same 8260 port as
the two existing stations and will not go through the Duplicate Address Test
procedure described above.
Note
With fan-out devices, the phantom signal on the port attaching the fan-out
device to the hub will be raised when the first station attached to the fan-out
device inserts into the ring. Therefore, a port connecting a fan-out device
with no active station will be in ″no phantom″ status and will have no entry in
the address-to-port map table.
Note: To allow the token-ring passive modules to perform address-to-port
mapping, when splitters and fan-out devices are used, you must issue the
following command:

SET NETWORK TOKEN_RING token_ring_n MISMATCH_RESOLUTION enable

8.10.1.2 Support for MAC-less Stations
The 8260 token-ring modules support the attachment of the MAC-less stations
(token-ring trace tools such as IBM DataGlance) without any specific action
required on the part of the user.
To support the MAC-less stations, if the Recovery ASIC detects the raising of a
phantom voltage on a port and then notes that the neighbor notification process
does not show any new MAC address associated with the new phantom voltage,
it assumes that the attached station to this port does not have a MAC address
and therefore, it sets an address of all zeros for the new port.
An example of the ″ring_map″ display for a module switching module with an
IBM DataGlance attached to port 4 is shown in Figure 101 on page 164.
Chapter 8. 8260 Token-Ring Support 163