Xerox NS-2260 - Manual (Page 20)

To provide path redundancy, Spanning-Tree Protocol defines a tree that
spans all switches in an extended network. Spanning-Tree Protocol forces
certain redundant data paths into a standby (blocked) state. If one network segment in the Spanning-Tree
Protocol becomes unreachable, or if
Spanning-Tree Protocol costs change, the spanning-tree algorithm
re-configures the spanning-tree topology and reestablishes the link by
activating the standby path.
Spanning-Tree Protocol operation is transparent to end stations, which
are unaware whether they are connected to a single LAN segment or a
switched LAN of multiple segments.
STP related parameters
Priority : A value to identify the root bridge. The bridge with the lowest value has the highest priority and
is selected as the root.
MAC Address : The MAC address of the switch as a unique identifier
to the network.
Max Age : The number of seconds a bridge waits without receiving Spanning Tree protocol configuration
messages before attempting a reconfiguration. Maximum Age Timer measures the age of the received
protocol information recorded for a port and ensures that this information is discarded when its age limit
exceeds the value of the maximum age parameter recorded by the switch. The time -out value for this timer
is the maximum age parameter of the switches.
Hello Time : The number of seconds between the transmission of Spanning Tree protocol configuration
messages. It determines how often the switch broadcasts its hello message to other switches.
Forward Delay Time : The number of seconds a port waits before changing from its Spanning Tree
Protocol learning and listening states to the forwarding state. Forward Delay Timer Monitors the time spent
by a port in the learning and listening states. The time -out value is the forward delay parameter of
Spanning tree port states
Listening : Switches send messages to one another to establish the network topology and the optimal paths
to the different segments of the network. Other data is not transmitted.
Blocking : The switch enters the Blocking State if a path with higher priority is found to exist during the
Listening State. Normal data is not transmitted.
Learning : The switch enters the Learning State if no path with a higher priority is found during the
Listening State. Learned entries are entered in the Unicast Destination Forwarding Table. Normal data
is not transmitted.
Forwarding : The switch enters the Forwarding State after having been in the Learning State for a
predefined time period. Normal data is transmitted.
Per port control settings
PathCost : Specifies the path cost for each port. The Spanning-Tree Protocol uses port path costs to
determine which port to select as a forwarding port. You should assign lower numbers to ports attached to
faster media (such as full duplex), and higher numbers to ports attached to slower media. The possible
range is 1 to 65535. The recommended path cost is 1000 divided by LAN speed in megabits per second.
Priority : Specify STP port priority for each port. The port (physical or logical) with the lowest priority
value has the highest priority and forwards the spanning-tree frames. The possible priority range is 0
through 255 (decimal). The default is 128. If all ports have the same priority value, the lowest port number
forwards the spanning-tree frames.
1.5.8 Port Sniffer Function
Port sniffer function is a method to duplicate all traffic occurred on the specified monitored ports to the
designated sniffer port. The traffic can be configured for incoming packets only or outgoing packets only or
both. The control settings are:
Sniffer Mode : Specify the traffic type for monitoring