Computer Networking Tutorials

Virtual Port Channel A port channel combines multiple physical link into a single logical link provided that these all physical links must belong to same network switch. However, in this case if our switch goes down we lose connectivity to all the devices connected to it. This is where virtual port channel comes to rescue. A virtual port channel allows you to bundles physical links spread across two separate physical switches. Following figures show simple port channel and virtual port channel topologies.  In this case Switch L runs simple port channel (LACP) because this switch has no idea that it is connecting to two different switches. But wait a minute how is that possible? With above topology it is not possible. We need little more on switch A and B side so that they can dodge Switch L to appear as single switch. We need to add extra physical links between Switch A and Switch B so that these switches can inform each other that they are both working on to fool

Introduction to Port channels (Etherchannel) One of the key feature of today’s networks is to be highly available. With increasing demand from our applications, network is supposed to provide more capacity on the links. Port channel is combining more than one physical links together. Logically these links appear as a single link. It can be seen below.  Port channel is also known as Etherchannel. Port channel is logical port on network switch which bundles underlying physical links. It is nothing but few configuration commands on network switch.   Different platform has different flexibility for maximum number of physical links a port channel can combine. For example In Cisco Nexus 5000 series switches you can bundle maximum 16 links together.   Please note that there is compatibility requirement in order to successfully bundle the links. In simple terms all the links should be of same gender and capabilities. For example speed, duplex, flow control, port mode,