STP is the short form for Spanning Tree Protocol & RSTP (Rapid Spanning shed some light on the differences between PVST and RPVST?. and fault-tolerance. STP, RSTP, PVST, and MST are all spanning tree protocols w What’s the difference between MSTP and OTN? Views · Are STP. To prevent loop between switches, Cisco uses Spanning-Tree protocol. STP is the The only difference here is using in Vlan instead of STP. The delay in.

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Much of the original The Layer 2 port does not participate in spanning tree and does not forward frames. When a port is in the blocking state, it does not forward traffic, but it can still process received BPDU messages. However, a switch running RSTP can communicate directly with a switch running the original Prevent from sending and receiving BPDU. Each instance can have a topology independent of other spanning tree instances.

The varieties of spanning-tree protocols include the following: Set initial configuration in Cisco devices. Alternate ports normally remain differenve the blocking state to logically break the loop topology.

I felt its a very good site for network engineers to keep up the knowlege about networking technologies.

The other switches in the network are called designated switches. RSTP can achieve much faster convergence in a properly configured network—sometimes in as little as a few hundred milliseconds. RSTP defines port states as discarding, learning, or forwarding. The delay in receiving BPDUs can cause problems like convergence time problems. Scaling Networks v6 Companion Guide. About Affiliates Cisco Systems, Inc. Learning — a situation where the switch creates a switching table that will map MAC addresses to a port number.

Root guard allows the device to participate in STP as long as the device does not try to become the root. Access-list Standard – Extended. On the root bridge, all ports are designated ports no root ports. The port moves to the STP forwarding state and creates a loop. Setup Router-on-a-Stick Layer 2 -Layer 3. RSTP does not have a blocking port state.

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Network loops sometimes happen inadvertently, especially in large networks. There are currently no related articles.

Understanding Spanning Tree Protocols – STP, RSTP, MSTP

For example, the RSTP spanning-tree algorithm elects a root bridge in exactly the same way as the original To facilitate the learning of the logical spanning tree, each switch port transitions through five possible port states and three BPDU timers.

RSTP has a collection of different ports, namely: Shared —A port operating in half-duplex mode connects a switch to a hub that attaches multiple devices.

Figure shows a network running RSTP. Protocol information can be immediately aged on a port if hello packets are not received for three consecutive hello times six seconds, by default or if the max age timer expires.

The disablement effectively denies devices behind such ports from participation in STP. As mstpp shown in below code, we have different instances and in each instance we have Vlans. You should probably delete this article.

As you can see in figure 1, we have 3 switches with the same priority and in the root bridge selection, switch with the lowest priority selects as a root bridge.

Blocking — happens when the port was blocked to stop a looping condition. It also happens when a port discards frames received on the interface, discards frames switched from another interface for forwarding, learns MAC addresses, and listens for BPDUs.

Varieties of Spanning Tree Protocols () > STP

The blocked links are not always discarded. Every answer has good example and explained very well.


The disabled state is set when the switch port is administratively disabled. Designated ports make the most use of the link-type parameter. RSTP is the preferred protocol for preventing Layer 2 loops in a switched network environment. It treats each VLAN as a separate network.

The link type can determine whether the port can immediately transition to a forwarding state, assuming that certain conditions are met. Figure shows examples of ports that can be configured as edge ports. STP is the simplest and oldest protocol which is enable by default in Stl devices. When you enable PortFast on the switch, spanning tree places ports in the forwarding state immediately, instead of going through the listening, learning, and forwarding states.

You must manually reenable the port that is put into errdisable state or configure errdisable-timeout. In our above diagram, Switch C could be considered as the Root bridge as it is in the central location.

The most secure implementation of PortFast is to enable it only on rst; that connect end stations to switches. The backup port which is a redundant path to a segment where another bridge port already connects. Because the bridge ID is based on the lowest MAC address, the switch chosen to be root bridge might not be the most powerful or the most optimal switch.

However, differencw the link-type parameter is considered, RSTP must determine the port role. Spanning Tree Configuration 3.

However, only one version can be active at any time. This port is called root port. The root bridge is the switch with the lowest bridge ID.