Alcatel Carrier Internetworking Solutions Omni Switch/Router - Manual (Page 477)

Configuring Spanning Tree
Page 17-29
Designated Root. The bridge identifier of the root of the spanning tree as determined by the
spanning tree protocol. It is created by concatenating the root bridge Priority with its six-byte
MAC address.
Cost to Root Bridge. The cost of the path to the root bridge as seen from this bridge. Cost
represents the distance of the group from the root bridge, in number of hops. If this is the
root bridge, this number is 0.
Root Port. The slot number, port number, and service type of the root port. The root port is
the bridge’s preferred path to the root bridge.
Next Best Root Cost. The next-best available cost of the path to the root bridge as seen from
this bridge. Cost represents the distance of the group from the root bridge, in number of
hops. If this is the root bridge, this number is 0.
Next Best Root Port. The next-best available root port (slot number, port number, and service
type). The root port is the bridge’s preferred path to the root bridge.
Hold Time. This time value determines the interval length during which no more than two
Configuration Bridge BPDUs shall be transmitted, in seconds.
Topology Changes. The total number of topology changes detected by this bridge since the
management entity was last reset or initialized. Topology changes happen when spanning
tree reconfigures to prevent logical loops from occurring.
Last Topology Change. The time since the last time a topology change was detected by the
bridge entity.
Bridge Aging Timer. The timeout period in seconds for aging out dynamically learned
forwarding information.
Max Age. The maximum age (in seconds) of spanning tree protocol information learned from
the network on any port before it is discarded.
Forward Delay. This time value (in seconds) controls how fast a port changes its spanning tree
state when moving toward the Forwarding state. The value determines how long the port
stays in each of the Listening and Learning states, which precede the Forwarding state. This
value is also used when a topology change has been detected and is underway to age out all
dynamic entries in the Forwarding Database.
Hello Time. The amount of time (in seconds) between the transmission of Configuration Bridge
Protocol Data Units (BPDUs) on any port when it is the root of the spanning tree, or trying to
become so.