Cisco Cisco FastHub 412M 10 100 Repeater
2
Limitations
OL-1543-05
Limitations
Limitations
The FastHub 400M can store up to 4096 MAC addresses in memory. The optional switched uplink
modules can store up to 1536 MAC addresses. If there is excessive flooding of unicast packets on these
devices, your hub or module might have reached its maximum. To clear the MAC address table,
power-cycle the hub. (CSCdk90641)
modules can store up to 1536 MAC addresses. If there is excessive flooding of unicast packets on these
devices, your hub or module might have reached its maximum. To clear the MAC address table,
power-cycle the hub. (CSCdk90641)
Usage Guidelines
•
Some 400 FastHubs have improperly terminated 100-MB TXEN signal lines at the extension port.
If this problem occurs when no extension module is present, 100-MB data can be corrupted.
Firmware version 1.00.02 and later detect the absence of an extension module and isolate the
extension port from the hub.
If this problem occurs when no extension module is present, 100-MB data can be corrupted.
Firmware version 1.00.02 and later detect the absence of an extension module and isolate the
extension port from the hub.
•
You must purchase and use the FastHub 400 stacking cable (part number WS-C400-CAB-EXP) to
create a hub stack of interconnected FastHub 400 models. Do not use any other cable for this
purpose. You can order this cable from your Cisco representative or reseller.
create a hub stack of interconnected FastHub 400 models. Do not use any other cable for this
purpose. You can order this cable from your Cisco representative or reseller.
•
A FastHub 400 does not support modem connections over a telephone line to a PC connected to
another modem by a telephone line. To connect to a FastHub 400 by using a modem, see your
modem manual for the correct configuration command syntax. (CSCdk83978)
another modem by a telephone line. To connect to a FastHub 400 by using a modem, see your
modem manual for the correct configuration command syntax. (CSCdk83978)
•
Before connecting a FastHub 400M model to a modem, configure your modem to ignore input from
the data terminal equipment (DTE) during dial-out or dial-in. Without this precaution, there is a
small chance that the modem could disconnect. See your modem manual for the correct
configuration command syntax. (CSCdk83009)
the data terminal equipment (DTE) during dial-out or dial-in. Without this precaution, there is a
small chance that the modem could disconnect. See your modem manual for the correct
configuration command syntax. (CSCdk83009)
Stacking Guidelines
When changing or moving units within a managed hub stack, note these configuration rules.
•
The stacking cable connectors are lockable. When you insert the stacking cable, be sure that it snaps
into place.
into place.
•
The stacking cables are not hot-swappable. You must power down the hub stack before connecting
or disconnecting a stacking cable. If you connect or disconnect a stacking cable while the power is
on, power-cycle the stack to ensure correct stack-management operation.
or disconnecting a stacking cable. If you connect or disconnect a stacking cable while the power is
on, power-cycle the stack to ensure correct stack-management operation.
•
The primary management hub is referred to as the M1 hub. The secondary management hub is
referred to as the M2 hub.
referred to as the M2 hub.
•
The M1 hub continuously stores the configuration settings for these stack elements:
–
Itself.
–
The three hubs that it has most recently managed (whether or not the hubs are currently being
managed).
managed).
–
TX and FX switched uplink modules for itself and for each of the three hubs that it has most
recently managed.
recently managed.
This means that if you remove a hub (other than the M1 hub) or module from the stack and later
reinstall the same device, the M1 hub might reconfigure that device with its former configuration in
the stack. Whether or not this happens depends upon whether the stored configuration for that
particular device has been retained by the M1 hub or overwritten in subsequent changes.
reinstall the same device, the M1 hub might reconfigure that device with its former configuration in
the stack. Whether or not this happens depends upon whether the stored configuration for that
particular device has been retained by the M1 hub or overwritten in subsequent changes.