Difference Between RSTP And PVST

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When configuring Spanning Tree Protocol (STP) on Ethernet networks, there are two choices: IEEE 802.1d spanning-tree protocol (STP), and Cisco’s proprietary PortFast and UplinkFast features. Although both STP and Cisco’s variants perform the same basic function-preventing loops-they have different feature sets and implementations. This article will explain the differences between RSTP and PVST.

What is RSTP ?

TheRapid Spanning Tree Protocol (RSTP) is a computer networking protocol that provides rapid recovery from failures in the network. It is based on the Spanning Tree Protocol (STP), which is a standard protocol. RSTP was first defined in IEEE 802.1w in 2001.

RSTP significantly reduces spanning tree convergence time after a topology change. The protocol achieves this by introducing new convergence behaviors and eliminating the need for the entire spanning tree to be recalculated.

RSTP operates by selecting a root bridge, which is typically the switch with the lowest MAC address. The root bridge then calculates the shortest path to every other switch in the network. RSTP uses a link-state algorithm, which means that it only recalculates the path when there is a change in the network topology.

What is PVST?

PVST is an acronym for Per-VLAN Spanning Tree. It is a Cisco proprietary protocol that provides Layer 2 loop prevention in a network. PVST+ is an enhanced version of the original PVST protocol and provides compatibility with IEEE 802.1Q-2003 standards.

PVST uses a separate spanning tree instance for each VLAN in a network. This allows for optimal path selection and utilization of redundant links while preventing loops. PVST+ adds support for multiple spanning tree instances on a single physical port, allowing for greater flexibility and scalability.

Main differences between RSTP and PVST

The two main types of Spanning Tree Protocol are PVST and RSTP. PVST is the original STP, while RSTP was developed to be faster and more efficient. Here are the key differences between these two protocols:

-RSTP converges much faster than PVST. This is because RSTP uses a simpler algorithm that doesn’t need to compute all possible paths through the network.

-RSTP can also use shorter hello intervals, which further speeds up convergence.

-RSTP supports link aggregation, while PVST does not. Link aggregation allows multiple physical links to be bundled together as a single logical link, which can improve redundancy and bandwidth.

Overall, RSTP is a much better choice than PVST for most networks.

Similar Frequently Asked Questions (FAQ)

What are the drawbacks of using RSTP over PVST?

There are a few drawbacks to using RSTP over PVST. One is that RSTP can cause more broadcast traffic than PVST. This can happen when multiple switches are connected in a loop and RSTP is used to prevent loops. Another drawback is that RSTP does not support VLANs as PVST does. This can be a problem if you need to use VLANs to segment your network.

In conclusion,while both RSTP and PVST improve upon the original STP protocol, they do so in different ways. RSTP focuses on being faster and more efficient, while PVST+ ensures compatibility with a wider range of devices. When choosing which protocol to use, it is important to consider the needs of your network.