IBM 8260 Support for Fan-Out Devices, Address-to-Port Map Display for a Module Switching Module

Now, DRA in ″TR Module 2″ starts tracking the stations that are involved in the neighbor notification process. The tracking will stop when the DRA in ″TR Module 2″ encounters an AMP/SMP MAC frame with the A/C bit set to B′0′, that is, AMP/SMP MAC frame issued by the NAUN to DRA. In this example, that would be the AMP/SMP MAC frame issued by station ″H″.

The stations that take part in the neighbor notification from the time that the URA sees an AMP/SMP MAC with the A/C bit set to B′0′ until the time DRA sees an AMP/SMP MAC with the A/C bit set to B′0′ (stations ″E″ thru ″H″ in our example) are the stations attached to this specific module (″TR Module 2″). These stations will then be associated with the ports that have a raised phantom voltage on the module. In this manner, the Recovery ASIC in each module is able to build the address-to-port map for its portion of the ring.

You can display the address-to-port map using the following DMM command:

SHOW RING_MAP TOKEN_RING LOGICAL token_ring_n or

SHOW RING_MAP TOKEN_RING LOGICAL isolated_n {slot}

An example of the output for this command for a module switching module with two active ports is shown in Figure 98.

￿					￿
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
	08-00-8f-40-01-a6		05.01	3
￿	8260>				￿

Figure 98. Address-to-Port Map Display for a Module Switching Module

When a new station on the module inserts into the ring, it raises a phantom voltage. The Recovery ASIC waits for the next neighbor notification process to occur to determine the new MAC address and associates that MAC address with the new port.

8.10.1.1 Support for Fan-Out Devices

The 8260 token-ring modules provide support for the attachment of up to a maximum of 8 stations to a single port through the use of fan-out devices (splitters).

Note

Currently, the 8260 only supports the fan-out devices and splitters that provide a phantom signal.

To understand how the address-to-port map is built for the fan-out attached devices, let′s assume that the module shown in Figure 99 on page 162 has a fan-out device attached to its second port and currently there is only a single station (station ″ B″) attached to the fan-out device. This is like having no fan-out

Chapter 8. 8260 Token-Ring Support 161