STP is the short form for Spanning Tree Protocol & RSTP (Rapid Spanning Tree Protocol), MSTP (Multiple Spanning Tree Protocol) are all. The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology In , the IEEE introduced Rapid Spanning Tree Protocol ( RSTP) as w. .. Cisco developed, implemented and published the Per- VLAN Spanning Tree (PVST) proprietary protocol using its own proprietary Inter- Switch. This lesson explains what is Rapid Spanning Tree Protocol (RSTP) Tutorials and Cisco enhanced the original Spanning Tree Protocol (STP) IEEE D.

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Verify your configuration on SW1. I am definetly enjoying this site and learning.

CCNA Training » Rapid Spanning Tree Protocol RSTP Tutorial

The number of states a port can be in has been reduced to three instead of STP’s original five. Thank you very much …. I want to understand the below points. Its possible and recommended to manually select the root switch.

Breaking ties for root ports: More Lessons Added Every Week!

This tutoril pretty much the backbone fast feature of classic spanning-tree. In each case, a single bridge may have multiple candidates for its root port. In other projects Wikimedia Commons.

Rapid Spanning Tree Protocol RSTP Tutorial

Its successor RSTP uses a similar formula with a larger numerator: Let me show you a new example with a port state that is new for rapid spanning-tree:. Rapid spanning tree can only put interfaces in the forwarding state really fast on edge ports portfast or point-to-point interfaces.

Bridge Protocol Data Unit. RSTP adds new bridge port roles in order to speed convergence following a link failure. Network loops sometimes happen inadvertently, especially in large networks. Root bridge is selected based on high bridge priority lowest value. Administrators can influence the protocol’s choice of the preferred path by configuring the port cost, the lower the port cost the more likely it tuotrial that the protocol will choose the connected link as root port for the preferred path.


If either L1 or L2 links rsstp, this link L3 automatically gets activated. BPDUs are now sent every hello time.

A Multi chassis link aggregation works like a normal LACP trunkonly distributed through multiple switches. The other switches in the network are called designated switches. Furthermore, the administrator can define alternate paths within a spanning tree.

Spanning Tree Protocol

Link failure at Edge port is not considered as topology change. The alternative port moves to the forwarding state if there is a failure on the designated port for the segment. The other switches non-root have to find the shortest cost path to the root bridge. This page was last edited on 15 Decemberat Do you remember all the other port roles that spanning-tree has? Some bridges implement both the IEEE and the DEC versions of the Spanning Tree Protocol, but their interworking can create issues for the network administrator, as illustrated by the problem discussed in an on-line Cisco document.

Breaking ties for designated ports: This command is executed from global configuration mode and manually sets the bridge priority per vlan on a switch. This preferred link is used for all Ethernet frames unless it fails, in which case the non-preferred redundant link is enabled.

Thanks for your excellent updates.

Spanning Tree Protocol – Wikipedia

If we enable portfast while running the classic spanning tree it will skip the listening and learning state and put the interface in forwarding state right away.

Please help Designated ports are selected based on the lowest path cost to the root bridge for a segment. Network protocols Link protocols Network topology Spanning tree Fault-tolerant computer systems Ethernet standards.


We use cookies to give you the best personal experience on our website. Very easy to understand the concepts!!! A new solution from an old technology”. In the classic spanning-tree the flags field only had two bits in use:. Several new features were added in the RSTP standard such as Edge Ports aka; PortFast which transitions an access port which can never become a layer2 loop in the network automatically to designated forwarding and does not have to listen and learn to determine which type of port type to assign to a particular port.

When this happens it will start the TC while timer which 2x hello 4 seconds in total and it will flush the MAC addresses that were learned on all non-edge interfaces.

There are two restrictions to the compatibility of VSTP:. STP will select the path with the lowest cost, that is the highest bandwidth, as the preferred link. STP will enable this preferred link as the only path to be used for Ethernet frames between the two switches, and disable all other possible links by designating the switch ports that connect the xisco path as root port.

The lower bridge ID is 24, so the tie breaker dictates that the designated port is the port through which network segment d is connected to bridge The sequence of events to determine the best received BPDU which is the best path to the root is:. Dear Rajesh, as usual a very nice article. Archived from the original PDF on 15 May