Filter
Top Products
•
Data B transmit
•
Clock receive
•
Data A receive
•
Data B receive
The reasons for two signals for each of the transmit and receive signals is given
in 8.2, “8260 Backplane Signalling for TR Segments” on page 134.
Note that regardless of the number of token-ring modules used in a segment,
you always have the ability to set up 10 separate token-ring segments on the
ShuntBus.
The same pins that are used for token-ring segments on the ShuntBus are
designed to be used for FDDI segments as well. Therefore, if you have a mixture
of token-ring and FDDI segments on the ShuntBus, the maximum number of
token-ring segments would be lower, depending on the number of FDDI
segments. However, this is a theoretical limitation for the time being, as
currently IBM is not offering any 8260 FDDI modules.
2.4 FDDI Segments on the Backplane
The 8260 allows you to set up a maximum of 4 FDDI segments on the Enhanced
TriChannel using the 8250 modules. Also, it is possible to set up a maximum of
4 FDDI segments on the ShuntBus, using the 8260 FDDI modules. However, as
there are no 8260 FDDI modules available yet, if you are planning to have FDDI
segments on the 8260, you must use the 8250 FDDI modules to set up FDDI
segments on the Enhanced TriChannel only.
Each FDDI module which is assigned to one of the four FDDI networks on the
Enhanced TriChannel uses one of the resources called
FDDI path
. There are 8
FDDI paths on the Enhanced TriChannel and are referred to as fddi_path_8250_1
through fddi_path_8250_8. Each FDDI path utilizes 6 pins of the Enhanced
TriChannel. These pins are as follows:
•
Data-in
•
Symbol parity-in
•
Clock-in
•
Data-out
•
Symbol parity-put
•
Clock-out
When you assign an FDDI module to one of the four FDDI networks on the
Enhanced TriChannel (fddi_1 through fddi_4), using the following command:
SET MODULE {slot.sublsot} NETWORK {FDDI_n}
the 8260 will automatically allocate one of the available FDDI paths to this
module. Note that you can neither choose the path used by a module, nor
determine which path is used by a specific module. However, you can
determine all the FDDI paths on the Enhanced TriChannel which are currently
being used in your hub by using the following management module command:
SHOW BACKPLNE_PATHS FDDI
22 8260 Multiprotocol Intelligent Switching Hub