--- title: Module 6 - 01 - STP Spanning Tree Protocol --- ###### tags: `__ccna_EN`,`Module 6` RemindeModule 6r ![](https://i.imgur.com/TGnKddi.png) Spanning Tree Protocol The spanning tree Protocol (STP) is a Network Protocol that builds a loop-free logical topology for Ethernet The basic function of STP is to prevent bridge loops and broadcast radiation that results from them As the name suggests, STP creates a spanning tree that characterizes the relationship of nodes within a network of connected layer-2 bridges, and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes. STP is based on an algorithm that was invented by Radia Perlman while she was working for Digital Equipment Corporation.[1][2] STP was originally standardized as IEEE 802.1D but the functionality of spanning tree (802.1D), rapid spanning tree (802.1w), and multiple spanning tree (802.1s) has since been incorporated into IEEE 802.1Q-2014.[3] ![](https://i.imgur.com/qaXGidD.png) KEY WORD -BPDU -STP Build topology on Packet Tracert Command **show spanning tree** ![](https://i.imgur.com/xg0lvjI.png) BPDU are data messages that are exchanged across the switches within an extended LAN that uses a STP topology. BPDU packets contain information on ports, adrdresses, priorities and costs and ensure that the data ends up where it was intended to go TCP/IP MODEL VS OSI Model ![](https://i.imgur.com/ZL3Ld8m.png) TCP/IP prefered protocol stack OSI Model is used to describe TPC/IP INTERNET LAYER / NETWORK LAYER ![](https://i.imgur.com/bUsWdVp.png) The best-known transport protocol of the Internet protocol suite is the Transmission Control Protocol (TCP). It is used for connection-oriented transmissions, whereas the connectionless User Datagram Protocol (UDP) is used for simpler messaging transmissions. TCP is the more complex protocol, due to its stateful design incorporating reliable transmission and data stream services. Together, TCP and UDP comprise essentially all traffic on the Internet and are the only protocols implemented in every major operating system. Additional transport layer protocols that have been defined and implemented include the Datagram Congestion Control Protocol (DCCP) and the Stream Control Transmission Protocol (SCTP) TCP, but not UDP, provide end-to-end reliable communication, i.e. error recovery by means of error detecting code and automatic repeat request (ARQ) protocol. The ARQ protocol also provides flow control, which may be combined with congestion avoidance. NETWORK LAYER Logical adressing (designing network) vlan / dhcp / Network access layer = datalink + physical layer type of signal (copper cable / Fiber / frequencies ) Netstat show all open protocol ![](https://i.imgur.com/5XkIu80.png) ![](https://i.imgur.com/v0ZGYTR.png)