RSTP

The ArubaOS implementation of RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. is as specified in 802.1w, with backward compatibility to legacy STP Spanning Tree Protocol. STP is a network protocol that builds a logical loop-free topology for Ethernet networks. 802.1D. RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. takes advantage of point-to-point links and provides rapid convergence of the spanning tree. RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. is enabled by default on all Aruba managed devices.

The ArubaOS RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. implementation interoperates with PVST Per-VLAN Spanning Tree. PVST provides load balancing of VLANs across multiple ports resulting in optimal usage of network resources. (Per VLAN Virtual Local Area Network. In computer networking, a single Layer 2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them through one or more routers; such a domain is referred to as a Virtual Local Area Network, Virtual LAN, or VLAN. Spanning Tree 802.1D) and Rapid-PVST Per-VLAN Spanning Tree. PVST provides load balancing of VLANs across multiple ports resulting in optimal usage of network resources. (802.1W) implementation on industry-standard routers or switches. Aruba only supports global instances of STP Spanning Tree Protocol. STP is a network protocol that builds a logical loop-free topology for Ethernet networks. and RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this.. Therefore, the ports on industry-standard routers or switches must be on the default or untagged VLAN Virtual Local Area Network. In computer networking, a single Layer 2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them through one or more routers; such a domain is referred to as a Virtual Local Area Network, Virtual LAN, or VLAN. for interoperability with Aruba managed devices.

ArubaOS supports RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. on the following interfaces:

FastEthernet IEEE Institute of Electrical and Electronics Engineers. 802.3: fastethernet

Gigabitethernet IEEE Institute of Electrical and Electronics Engineers. 802.3: gigabitethernet

Port Channel ID: port-channel

Since RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. is backwards compatible with STP Spanning Tree Protocol. STP is a network protocol that builds a logical loop-free topology for Ethernet networks., it is possible to configure both bridges in the same network. However, such mixed networks may not always provide rapid convergence. RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. provides rapid convergence when interfaces are configured as either:

Edge ports: These are the interfaces or ports connected to hosts. These interfaces are immediately moved to the forwarding state. In this mode, an interface forwards frames by default until it receives a BPDU Bridge Protocol Data Unit. A BPDU is a data message transmitted across a local area network to detect loops in network topologies., indicating that it should behave otherwise. It does not go through the Listening and Learning states.

Point-to-Point links: These are the interfaces or ports connected directly to neighboring bridges over a point-to-point link. RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. negotiates with the neighbor bridge for rapid convergence or transition only when the link is point-to-point.

Table 1: Port State Comparison

STP (802.1D)

Port State

RSTP (802.1W) Port State

Disabled

Discarding

Blocking

Discarding

Listening

Discarding

Learning

Learning

Forwarding

Forwarding

In addition to port state, RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. introduces port roles for all the interfaces (see Table 2).

Table 2: Port Role Descriptions

RSTP (802.1W) Port Role

Description

Root

The port that receives the best BPDU Bridge Protocol Data Unit. A BPDU is a data message transmitted across a local area network to detect loops in network topologies. on a bridge.

Designated

The port can send the best BPDU Bridge Protocol Data Unit. A BPDU is a data message transmitted across a local area network to detect loops in network topologies. on the segment to which it is connected.

Alternate

The port offers an alternate path, in the direction of root bridge, to that provided by bridge’s root port.

Backup

The port acts as a backup for the path provided by a designated port in the direction of the spanning tree.

The RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. port interface is designated as point-to-point, by default, in the existing port configuration screen. The following procedure configures RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this.:

1. In the Mobility Masternode hierarchy, navigate to Configuration > Interfaces > Ports.

2. In the Ports table, click the port number for which you want to enable RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. or STP Spanning Tree Protocol. STP is a network protocol that builds a logical loop-free topology for Ethernet networks. features.

3. Select the Show Advanced Options link at the bottom of the Ports tab.

4. Enable Spanning Tree.

5. (Optional) Define values for the following Spanning Tree configuration parameters:

Cost: Defines the RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. interface path cost. The cost prioritizes routing to the destination. The lower the cost, the higher the priority.

Priority: Sets the interface’s RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. priority. The supported range is 0–255, and the default value is 128.

Port Fast: Changes from blocking to forwarding mode, enabling forwarding of traffic from the interface.

Point-to-Point: Sets the interface as a point-to-point link.

6. Click Submit.

7. Click Pending Changes.

8. In the Pending Changes window, select the check box and click Deploy changes.

The following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. commands change the default configurations:

(host) [mynode] (config) #interface gigabitethernet <slot>/<module>/<port>

(host) [mynode] (config-if) #spanning-tree

cost <value>

point-to-point

port-priority <value>

portfast

The following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. commands can be used to view settings and troubleshoot RSTP Rapid Spanning Tree Protocol. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. issues:

The show spantree command displays the root and bridge information, verifying that they are correct. The port or interface information (example: state, role, and so on) is also displayed to make sure that the state and role information correspond with each other. For more details and examples on the show spantree command, refer to show spantree in the ArubaOS CLI Reference Guide.

The show spanning-tree interface command (config-if mode) displays Tx or Rx BPDU Bridge Protocol Data Unit. A BPDU is a data message transmitted across a local area network to detect loops in network topologies. counters. For example, if a port’s role is designated, it only transmit BPDUs but does not receive any. In this case, the Tx counter continues to increase in increments while the Rx counter remains the same. This is reversed when the role of a port is root/alternate/backup. For more details and examples on the show spanning-tree interface command, refer to show spaning-tree in the ArubaOS CLI Reference Guide.