3Com 2848-SFP Plus User Manual page 43

Figure 25 Upgrade Screen
Once you have downloaded the software, use the
Browse button to locate the file on your computer, and
then click on Apply.
You may need to change the file type in the dialog box
displayed by your Web browser to *.* to be able to see
the file.
The file will be copied to the Switch, and once this has
completed, the Switch will restart. Although the
upgrade process has been designed to preserve your
configuration settings, 3Com recommends that you
make a backup of the configuration beforehand, in case
the upgrade process fails for any reason (for example,
the connection between the computer and the Switch is
lost while the new software is being copied to the
Switch).
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The upgrade procedure can take a few minutes, and is
complete when the Power LED has stopped flashing and
is permanently green. Make sure that you do not
interrupt power to the Switch during the upgrade
procedure; if you do, the software may be corrupted
and the Switch may not start up properly afterwards. If
the Power LED continues to flash after a failed upgrade,
refer to "Troubleshooting" on page 45.
Spanning Tree
This administrative tool supports the configuration of
the Switch to forward, or block and discard 802.1D
spanning tree BPDU packets.
Spanning tree is a bridge-based system for providing
fault tolerance on networks and can be used to detect
and disable network loops. The spanning tree ensures
that the optimal path is maintained between spanning
tree-compliant networked devices by:
Disabling redundant paths when the main paths are
■
operational.
Enabling redundant paths if the main paths fail.
■
Spanning tree uses a distributed algorithm to select a
bridging device that serves as the root of the spanning
tree network. The bridging device known as the Root
Bridge generates BPDUs (Bridge Protocol Data Units) on
all ports at a regular interval known as the Hello Time.
All other spanning tree-compliant devices on the
network have a designated Root Port. This is the Port
nearest the Root Bridge and it is used for receiving the
Using the System Tools 43