2. The 8250 module sends
module type
information to the Controller module.
The Controller module has no information about how much power is
consumed by the module at this stage.
3. TheController module forwards the
module type
of the newly inserted 8250
module to DMM.
4. DMM has a table which specifies the amount of power required by each 8250
module. This table contains an entry for each
module Type
. DMM retrieves
the power requirements of the newly installed module from this table.
5. DMM sends the module′s power requirements to the Controller module.
6. Controller module updates its power budget table. A t this stage you will be
able to display the correct power budget available in the hub using DMM
commands.
The process of applying power to a newly installed 8250 module in an 8260
managed hub via DMM is shown in Figure 53.
Figure 53. Installing 8250 Modules in an 8260 Managed by DMM
Note: If the power consumption of the newly installed 8250 module results in
a power deficit (that is, the total power required by the currently installed
modules exceeds the available power supply) the Controller module cannot
prevent the power from being used by the newly installed module.
Therefore, if you do not check the available power budget in your hub before
installing an 8250 module, you may have a situation where the total power
consumed by the modules exceeds the available power budget. In this case,
the hub may be reset. Following the reset, power will be applied to all the
8250 modules and all the 8260 modules in the order of their power class and
slot position as described in 5.2, “Power Class” on page 74. This may result
in one or more existing 8260 modules with low power class being denied
power after the hub is reset. Therefore, you are strongly advised to ensure
that there is enough power available in your hub before you attempt to
install a new 8250 module in the 8260. You may refer to the tables provided
in Appendix A, “Power Requirements for 8250/8260 Modules” on page 315 to
determine the power requirements of the 8250 modules.
84 8260 Multiprotocol Intelligent Switching Hub