Trunk Protocol VLAN from VTP allows a network administrator to configure a switch so that propagate the VLAN configurations to other switches in the network. BENEFITS: Consistency in the VLAN configuration through the network, accurate tracking and monitoring of VLANs Dynamic Reports on VLANs that are added to a network, dynamic trunk configuration when VLANs are added to the network. MODES: server, client, or transparent. The benefit of VTP is automatically distributed and synchronizes the domain and VLAN configurations across the network. Show vtp status Displays the network status and recommended vtp run whenever there is a change or update the vtp. A plot of VTP consists of a header field and a message field. The VTP information is inserted into the data field of an Ethernet frame.Server mode: You can create, modify and delete VLANs for the VTP domain complete. Is the default mode of the switch. Transparent mode: The mode switches configured in VTP transparent sent publications they receive in their trunk ports to other switches in the network. Transparent mode switches do not publish your settings and do not synchronize its VLAN configuration any other switch. Layer 2 redundancy improves network availability by implementing alternate network paths by adding equipment and cables. By having multiple paths for data transmission on the network, disruption of a single route generates no impact on the connectivity of network devices. Disadvantages Redundancy When there are multiple paths between two devices on the network and STP has been disabled on the switches, there can be Layer 2 loop. If STP is enabled on the switches, which is what is predetermined, the Layer 2 loop can be avoided, The Ethernet frames do not have a time to live.A broadcast storm occurs when there are so many broadcast frames trapped in a Layer 2 loop that consumes all available bandwidth. Consequently, there is available bandwidth for legitimate traffic and the network is not available for data communication. Duplicate Unicast Frames Frames broadcast are not the only type of frames that are affected by the loops. The unicast frames sent to a network with loops may generate duplicate frames that reach the target device. STP ensures that there is only one logical path between all network destinations, intentionally blocking those redundant paths that can cause a loop . STP uses the spanning tree algorithm (STA) to determine the ports of network switch to be configured for blocking, and thus avoid the generation of loops. The whole root bridge spanning-tree instance (switched LAN or broadcast domain ) has a switch designated as the root bridge. SQRT Bridge serves as a reference point for all spanning-tree calculations to determine the redundant paths to be blocked. BPDU hello packets STP protocol that sends configurable intervals to exchange information between network bridges. Configure and BDI change Method 1: spanning-tree vlan vlan-id root primary spanning-tree vlan vlan-id root secondary, Configure and verify the IDB (Cont.) show spanning-tree. FUNCTIONS OF PORTS Puerto Root: The root port exists on the bridges that are not root and is the switch port with the best path to the root bridge. Designated Port: The port designated exists at the root bridge and the non - root. For root bridges, all switch ports are designated. For non-root bridge, a designated port is the switch that receives and sends frames through the root bridge as neededNon-designated port: The port is not designated switch port that is locked, so it does not send data frames or full MAC address table with source addresses. Puerto disabled: The disabled port is a switch port that is administratively offline. verify the root port with the command show spanning-tree privileged EXEC mode. Protocol spanning tree per VLAN (PVST) maintains a spanning-tree instance for each VLAN configured on the network. Use the handshake Cisco proprietary ISL backbone that allows a VLAN trunk link is in a state of sending for some VLANs and lock status for others. Protocol per VLAN spanning tree plus (PVST +) provides the same functionality as PVST, including extensions of Cisco proprietary STP. PVST + is not supported on devices that are not of Cisco.VLAN spanning tree protocol for fast (rapid PVST +) is based on IEEE 802.1w and has a faster convergence than STP (802.1D standard). Includes rapid PVST + Cisco proprietary extensions, as BackboneFast, UplinkFast and PortFast. Rapid Spanning Tree Protocol (RSTP) provides a convergence of spanning-tree faster after a topology change. Multiple STP (MSTP) allows you to assign VLAN multiple to the same instance of spanning-tree, so reducing the number of instances required to support a large number of VLANs. RSTP RSTP (IEEE 802.1w) is an evolution of the 802.1D standard. Principally, the 802.1w STP terminology remains the same as the IEEE 802.1D STP. Most parameters are unchanged, so that users familiar with STP can quickly configure the new protocol.