3Com 3CR17251-91 - Switch 5500G-EI Stackable Gigabit Ethernet Getting Started Manual page 82

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If your IP network is internal to your organization only, that is, you do not
access the Internet, you may use any arbitrary IP address as long as it is
not being used by another device on your network. 3Com suggests you
use addresses in the range 192.168.0.0 to 192.168.255.255 with a
subnet mask of 255.255.255.0.
These suggested IP addresses are part of a group of IP addresses that
have been set aside specially for use 'in house' only.
A device is connected to a Switch 5500 PWR or Switch 5500G-EI
but power is not being supplied
If power is not being supplied to a device connected to a Switch 5500
PWR, you should do the following checks:
Check that the device is compliant with 802.3af standard.
■
The Switch 5500 PWR will only supply power through the front panel
port to 802.3af compliant devices.
Check that the power budget for the Switch has not been exceeded.
■
If the power budget is exceeded, then by default, the powered device
connected to the Power over Ethernet port with the lowest priority
port will lose power. However, if all the devices connected to the
Switch have equal priority levels, then the port with the highest
number will lose power.
By default, the Switch will allow a device to receive power as long as
Power over Ethernet power supply has 18 watts spare in its power
budget. If this much power is not available, the device will not be
powered (unless it has a higher priority than existing powered ports)
and a PoE fault will be reported for that port. If enough power
subsequently becomes available, the port will be powered.
Check that the port has not had a power limit imposed on it.
■
The Switch 5500 PWR units do not provide PoE on the Gigabit SFP ports.