Root Bridge - EnGenius EWS Series User Manual

This can result in the loss of communication between various parts of the network during the
convergence process so STP can subsequently lose data packets during transmission.
RSTP on the other hand is much faster than STP. It can complete a convergence in seconds, so it greatly
diminishes the possible impact the process can have on your network compared to STP. RSTP reduces
the number of state changes before active ports start learning, predefining an alternate route that can
be used when a node or port fails and retain the forwarding database for ports insensitive to changes in
the tree structure when reconfiguration occurs.
Select whether to Enable or Disable the Spanning Tree function for the Switch. Next, select whether you
wish to enable STP, RSTP, or MSTP. Again, please note that only one Spanning tree function can be active
at a time.
Click Apply to save settings.

Root Bridge

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.
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