Rapid Spanning Tree Protocol (RSTP) is an improved and advanced version of STP which is a layer 2 protocol that prevents bridge loops and broadcast storms in local networks with redundant connections. RSTP has faster convergence, and it is also backward compatible with STP. To make sure a loop-free topology, the RSTP precludes some of the connections which permit only a single active path between any two devices. All these disabled connections can be used as backup paths in case an active connection fails. is the more improved and advanced version of STP which is a layer 2 protocol that prevents bridge loops and broadcast storms in local networks with redundant connections. Rapid spanning tree protocol has faster convergence, and it is also backward compatible with STP. To make sure a loop-free topology, the RSTP precludes some of the connections which permit only a single active path between any two devices. All these disabled connections can be used as backup paths in case an active connection fails.
 

The RSTP Menu Bar displays RSRP Status.

Access to RSTP is located on the ONT UNI Port Menu Bar.

 

 

The RSTP parameters include the following:

• Port Role - The role assigned this port. Options are Designated, Backup, Root, or Alternate. 
  • Designated - Responsible for forwarding the traffic coming from the spanning-tree root onto this segment. 
  • Backup - A backup for the designated port.  
  • Root - The root port of a bridge is the port closest to the root bridge. It is responsible for carrying the traffic from this segment toward the root bridge, using the shortest path to reach the root.
  • Alternate - A backup for the root port.
  • Master - The best possible path to reach the common internal spanning-tree (CIST) root bridge from any MSTP region.
  • Disabled -
    • Port is disabled
    • Port does not have an enabled RSTP profile applied
    • Port does not have a NAC/Service profile applied
• Port Forwarding State - Current state of the MSTP port. Options are Blocking, Listening, Learning, Forwarding, or Disabled.
  • Blocking - A port in the blocking state does not participate in frame forwarding and also discards frames received from the attached network segment. During blocking state, the port is only listening to and processing BPDUs on its interfaces. After 20 seconds, the switch port changes from the blocking state to the listening state.
  • Listening - After a blocking state, a root port or a designated port moves to a listening state. All other ports remain in a blocked state. During the listening state, the port discards frames received from the attached network segment and it also discards frames switched from another port for forwarding. At this state, the port receives BPDUs from the network segment and directs them to the switch system module for processing. After 15 seconds, the switch port moves from the listening state to the learning state.
  • Learning - A port changes to a learning state after a listening state. During the learning state, the port lists for and processes BPDUs. In the listening state, the port begins to process user frames and starts updating the MAC address table. But the user frames are not forwarded to the destination. After 15 seconds, the switch port moves from the learning state to the forwarding state.
  • Forwarding - A port in the forwarding state forwards frames across the attached network segment. In a forwarding state, the port processes BPDUs, updates its MAC Address table with frames that it receives, and forwards user traffic through the port. The Forwarding State is the normal state. Data and configuration messages are passed through the port when in forwarding state.
  • Disabled - A port in the disabled state does not participate in frame forwarding or the operation of STP because a port in the disabled state is considered non-operational.
• Designated Root - The MAC address of the root that sent the best BPDU that was received on this port. 
• Designated Bridge - The MAC address of the bridge that sent the best BPDU that was received on this port. 
• CST Regional Root - The MAC address of the Common Spanning Tree (CST) Root Bridge for the local region. 
• Designated Cost - The cost of sending traffic through the interface to adjacent bridges within a spanning tree region.
• Designated Port - The uplink port designated for this uplink.
• Edge Port - Indicates if the port is configured as an Edge Port
  • (True) or not (False).
• Point-to-Point MAC - Indicates if the port is configured as a point-to-point link
  • (True) or not (False)
• CST Path Cost - The default path cost assigned to an interface according to the selected CST configuration method
  • (Hello Time, Max Age, or Forward Delay).

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