Connect a Cisco switch and router via 802.1q trunking. This configuration is known as a router-on-a-stick.

Cisco Discover Protocol or CDP is a Cisco-proprietary protocol that runs on all Cisco products. CDP allows devices to learn about neighboring devices (the ones attached directly to the switch) including information about their platform, IP address, the version of IOS or other OS, VLAN membership, etc. This can be helpful information when troubleshooting network [...]

The commands for creating a VLAN vary from one switch model to another. VLANs in a 2950 switch are configured in a manner similar to configuring an interface. This configuration is substantially different than a 2900 switch.

A VLAN (Virtual Local Area Network) makes a single physical switch behave like several separate switches. A host connected to one VLAN cannot communicate through the switch to a host connected to another (although a router can permit communication between VLANs, if desired). Here is how to configure a new VLAN on a 2900 switch.

Knowing the commands to display configuration information about Virtual LANs (VLANs) is as important as knowing the commands to configure them. The commands here display information about all VLANs or a single VLAN by number or name.

This documents the procedure for performing a password recovery on a Cisco 2950 switch (and probably other models, as well).

This small guide can be useful if you need to configure the RSPAN session on your Catalyst 6500.In this example we will see how to monitor more than one VLan using the RSPAN vlan. RSPAN has all the features of SPAN plus support for source ports and destination ports distributed across multiple switches, allowing remote [...]

Sometimes you need to know which switch and port you are connected to. I work for a community college with hundreds of switches. Here is a method I’ve found to work well.

Removing a port from a VLAN on a Cisco 2950 switch is a simple operation. Follow the steps in this simple Tech-Recipe.

When you use spanning tree, a root switch is designated for you. However, knowing the location of the root switch makes troubleshooting a switched network much easier. Furthermore, by “manually setting” a root switch, you can use your most powerfull switch to become the root.