Spanning Tree Protocol and Switching Crystal Kaplan University Spanning Tree Protocol and Switching You would only want to use half-duplex when there is only a single network medium between devices such as cable or radio frequency. Half-duplex is capable of sending information in both directions between two nodes, but only one direction can be utilized at a time. An Ethernet switch has multiple Ethernet ports, typically from 4 up to 32 ports or more.
Each port is its own collision domain. That's the fundamental difference between a hub and a switch. Show ip displays configuration and statistics.Show running-config displays the switch configuration currently running.
Show flash displays the layout and contents of flash memory. Show startup-config which displays the switch configuration stored in nonvolatile RAM (NVRAM). Blocking— a blocked port won’t forward frames: it just listens to BPDUs. The purpose of the blocking state is to prevent the use of looped paths. All ports are in blocking state by default when the switch is powered up. Listening— the port listens to BPDUs to make sure no loops occur on the network before passing data frames.
A port in listening state prepares to forward data frames without populating the MAC address table. Learning—the switch port listens to BPDUs and learns all the paths in the switched network. A port in learning state populates the MAC address table but still doesn’t forward data frames. Forwarding—the port sends and receives all data frames on the bridged port. Disabled—a port that is in the disabled state can not participate in the frame forwarding or STP and is virtually nonoperational. The STP protocol allows switches to have redundant connections, while avoiding problems associated with switching loops.
For example, if there is a switching loop, a broadcast would go around in circles indefinitely. There are other problems, too. The STP protocol disables enough connections so that there are no loops; the disabled connections are in "stand-by" and can be enabled again when other connections fail, thus providing the desired redundancy. Reference: Lammle, T. (2011). CCNA Cisco Certified Network Associate Study Guide Seventh Edition.
Wiley Publishing, Inc. Cisco. (n. d. ) Troubleshooting Tools.
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