Much like with Cisco routers, it’s generally a good idea to back up the configuration of your switches as well. The syntax to copy the configuration of a Catalyst 1900 series to a TFTP server is different than on a router, although it does following a similar “copy from to” format. The example below shows […]

The purpose of the Spanning Tree Protocol (STP) is to prevent loops on a switched or bridged network. STP is enabled on Catalyst 1900 series switches by default. In fact, one instance of Spanning Tree is enabled for each and every VLAN.
In earlier articles we examined some of the default settings relating to the Spanning […]

The VLAN Trunking Protocol (VTP) is used to manage the configuration of switches that are part of a VTP management domain, as we learned in Chapter 3. Recall that three VTP modes exist – server, client, and transparent mode. Once a VTP server is configured, any changes made (such as adding or removing VLANs) will […]

Earlier in Chapter 3, we looked at ways to connect switches with trunk links, such that VLANs could span multiple switches. The two main ways to accomplish this are via the Inter-Switch Link (ISL) and 802.1q frame tagging methods. The Cisco 1900 series does not support 802.1q, leaving ISL as the only option for creating […]

A VLAN is essentially a broadcast domain, assigned according to switch ports. By default, all ports on a Cisco 1900 are assigned to VLAN 1, sometimes referred to as the management or administrative VLAN. In order to implement additional VLANs, you will first need to define them, and then add ports to that VLAN. New […]

The Cisco Discovery Protocol (CDP) is used to gather information about neighboring Cisco devices. Cisco 1900 series switches also run CDP, with the same default parameters as a CDP-enabled router. The show cdp command shows the current CDP version, as well as CDP timer and holdtime intervals. The show cdp neighbors command will display a […]

A switch makes forwarding decisions based on the entries stored in its MAC address table. This table is built as the switch inspects the source addresses of frames as they enter the switch from devices connected to a given port. By default, a Catalyst 1900 switch can store up to 1024 entries in its MAC […]

A Cisco 1900 is basically a plug-and-play switch. This means that you can treat a 1900 much like a hub by simply plugging computers (or other hubs) into its ports and allowing them to communicate. One reason this works is that all ports are part of the same VLAN by default. However, you may want […]

Recall from Chapter 3 that Cisco switches support three major switching methods – FragmentFree, Cut-Through, and Store-and-Forward. The Catalyst 1900 series supports only two of these methods, FragmentFree and Store-and-Forward. FragmentFree is the method configured by default.
To view the current switching method enabled on a switch, use the show port system command. To change the […]

The commands to view and save the configuration settings on a Cisco 1900 switch are similar to those on a Cisco router, with a few small exceptions. To view general information about the switch itself, including its software version, hardware platform, MAC address, memory configuration, and so forth, use the show version command.
Cisco1912#show version
Cisco Catalyst […]