Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 304)

CLI display of 802.1W summary (Continued) TABLE 49
Field Description
txHoldCnt The number of BPDUs that can be transmitted per Hello Interval. The default is 3.
Root Bridge
Identifier ID of the Root bridge that is associated with this bridge
Root Path Cost The cost to reach the root bridge from this bridge. If the bridge is the root bridge, then this
parameter shows a value of zero.
Designated Bridge
Identifier The bridge from where the root information was received.It can be from the root bridge itself,
but it could also be from another bridge.
Root Port The port on which the root information was received. This is the port that is connected to the
Designated Bridge.
Max Age The max age is derived from the Root port. An 802.1W-enabled bridge uses this value,
along with the hello and message age parameters to compute the effective age of an RST
BPDU.
The message age parameter is generated by the Designated port and transmitted in the
RST BPDU. RST BPDUs transmitted by a Designated port of the root bridge contains a
message value of zero.
Effective age is the amount of time the Root port, Alternate port, or Backup port retains the
information it received from its peer Designated port. Effective age is reset every time a port
receives an RST BPDU from its Designated port. If a Root port does not receive an RST
BPDU from its peer Designated port for a duration more than the effective age, the Root port
ages out the existing information and recomputes the topology.
If the port is operating in 802.1D compatible mode, then max age functionality is the same as
in 802.1D (STP).
Fwd Dly The number of seconds a non-edge Designated port waits until it can apply any of the
following transitions, if the RST BPDU it receives does not have an agreed flag:
• Discarding state to learning state
• Learning state to forwarding state
When a non-edge port receives the RST BPDU it goes into forwarding state within 4
seconds or after two hello timers expire on the port.
Fwd Dly is also the number of seconds that a Root port waits for an RST BPDU with a
proposal flag before it applies the state transitions listed above.
If the port is operating in 802.1D compatible mode, then forward delay functionality is the
same as in 802.1D (STP).
Hello The hello value derived from the Root port. It is the number of seconds between two Hello
packets.
Port IEEE 802.1W parameters
Port Num The port number shown in a slot#/port# format.
Spanning Tree Protocol
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