In order to bundle multiple interfaces between switches in an effort in increase throughput, a Ether Channel can be created. Ether Channels can be created as Layer 2 or Layer3. The obvious difference between the 2 is that a Layer 3 link will have a IP address associated and hence traffic can be routed between the […]
In order for 2 VLANS to be able to communicate, the traffic must be routed. This can be done either by a multi-layer switch which will have routing capabilities, or the packets can be routed by a router (Router on a Stick) As an example, I have 2 VLANS, VLAN 10 and VLAN 20 which […]
VTP (VLAN Trunking protocol) is a protocol used to replicate the VLAN information across switches, however there are a few things that must be made clear… VLAN information will only be sent on trunk ports Only the VLAN identity is replicated, NOT which ports are configured to use that VLAN! Maintains database consistency through a […]
Although the configuration of speed and duplex is incredible easy, the concept behind them is somewhat important. Duplex defines how traffic will be sent and can be related to a 2-way radio vs. A telephone. With a 2-way radio, more so when there are more than 2 people on the same radio frequency, only 1 […]
A VLAN is a Virtual LAN which allows us to logically separate computers on our network. In previous years, an office would have a physical switch or hub in each office, and offices were structured around the job function. In other words, all sales people would be in the same office and would all be […]
In order to control what machines are plugged into your network, Cisco introduced the “switchport port-security” command. In this tutorial I’m going to explain how to use this command, and different options available using it. Below is the breakdown of the commands I used in the live demo, and an explanation of each. AOIP.ORG_Switch# terminal […]
Once VLANS have been defined on a switch and you have placed ports into their corresponding VLANS, traffic is limited to remain inside it’s Virtual LAN. The only way for traffic to leave the switch, is to have it sent on a port that is in the same VLAN as its source, or sent over […]
Almost 100% of Cisco switches will have a 50 second delay on a port before it goes live. What this means, is that when you plug a new device into a switch such as a PC, there will be a 50 second delay before the port will become active and the PC will be able […]
The configuration of an IP address and default-gateway on a switch is slightly different from a router. Firstly a router doesn’t have a default-gateway but rather a default route. A switch on the other hand can have a default-gateway, especially if the device is in layer 2 mode. If the switch is a multi-layer switch […]
SPAN (Switched Port Analyser) is a requirement whenever you have a system that wishes to log and monitor traffic that is passing through a switch. Since a switch only sends traffic to the machine requiring the packets, adding a sniffer to the switch would result in you only seeing traffic to your sniffer, from your […]