Owner's Manual

34
Hello Time
Displays the Switch Hello Time. This is the amount of time a bridge remains
in a listening and learning state before forwarding packets. The default is
15 seconds.
Click Apply to save settings.
The Root Bridge serves as an administrative point for all Spanning Tree calculations to determine
which redundant links to block in order to prevent network loops. From here, you can view all the
information regarding the Root Bridge within the STP.
All other decisions in a spanning tree network, such as ports being blocked and ports being put in
a forwarding mode, are made regarding a root bridge. The root bridge is the “root” of the
constructed “tree” within a spanning tree network. Thus, the root bridge is the bridge with the
lowest bridge ID in the spanning tree network. The bridge ID includes two parts; the bridge priority
(2 bytes) and the bridge MAC address (6 bytes). The 802.1d default bridge priority is: 32768. STP
devices exchange Bridge Protocol Data Units (BPDUs) periodically. All bridges “listen” for Hello
BPDUs (Bridge Protocol Data Units) transmitted from the root bridge. If a bridge does not get a
Hello BPDU after a predefined interval (called the Maximum Age), the bridge assumes that the link
to the root bridge is down. The bridge then initiates negotiations with other bridges to reconfigure
the network to re-establish a valid network topology.