Dell PowerConnect B-RX4 BigIron RX Configuration Guide (Supporting Multi-Servi - Page 456

13 Displaying RSTP information TABLE 77 CLI display of RSTP summary (Continued) This field... Displays... Root bridge parameters: Root Bridge Identifier Root Path Cost Designated Bridge Identifier Root Port Max Age Hello Fwd Dly RSTP (IEEE 802.1W) port parameters ID of the Root bridge that is associated with this bridge 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. 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. The port on which the root information was received. This is the port that is connected to the Designated Bridge. The max age is derived from the Root port. An RSTP-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). The hello value derived from the Root port. It is the number of seconds between two Hello packets. 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). Port Num Pri Port Path Cost P2P Mac The port number shown in a slot#/port# format. The configured priority of the port. The default is 128 or 0x80. The configured path cost on a link connected to this port. Indicates if the point-to-point-mac parameter is configured to be a point-to-point link: • T - The link is configured as a point-to-point link. • F - The link is not configured as a point-to-point link. This is the default. 384 BigIron RX Series Configuration Guide 53-1001810-01