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Its the first major topic of our Cisco switch world. Well to start of let me tell you one secret, if you are using a managed switch, you are using VLANs, so its not that alien of a topic. Yes its true even if you have not came across setting up VLANs while configuring your networks (using managed switches), you are using VLAN, as its default “VLAN 1” every port of a managed switch belongs to VLAN 1 by default. So what is VLAN, lets start with a brief discussion of what switches do; Well they are the Layer 2 (OSI) device and divide collision domain on per port basis i.e. each port of a switch is a separate collision domain. But by default it does not divide the broadcast domain. To have separate broadcast domains we need a layer 3 device like a router. But there is a mechanism to divide broadcast domain at layer 2, and that mechanism is referred as VLANs. VLANs logically group users by segmenting broadcast domain. As per Cisco, VLANs = Broadcast Domain = Subnet End nodes on a giv

Starting off where we had left it from last post..As we have already covered the first three points, we are going to look into management of the swtich: MANAGEMENT We are going to enable the remote management features of the switch/router, so we don’t have to stand in those cold IT rooms while configuring or monitoring our devices. To start we will look from a perspective of a configuring a Cisco switch. Ethernet allow devices to exchange packets (aka communicate) inter-network with the aid of IP addressing and our case being no exception, we will start by allocating an IP address to our switch.. hmm.. Well some of might be confused by the fact that as switches are layer 2 devices and work with MAC addresses. So what on Earth make us allocate an IP address that is a Layer 3 (refer OSI model) to a layer 2 device like switch. Well it is done solely for remote management purpose. Sounds Alright.. but hey if all the ports on a Switch are layer 2, where are we going to provide the IP a

We can start off our campaign by configuring a small LAN network. We will configure a cisco switch that is connected to end user device and eventually forward traffic to a router with connects our LAN with outside network/ Internet. In our scenario, the configuration will be done on the switch, here we are going to divide the whole process into six stages: 1) Beginning: start up new switch/ wipe out existing configs. 2) Security: passwords & banner. 3) Cosmetics: name & work environment. 4) Management: IP address & gateway. 5) Interfaces: speed, duplex & description. 6) Verify & backup: CDP, TFTP, show interfaces. BEGINNING Very few of us will be born with the silver spoon to have a brand new switch to start off the proceedings, for other not so lucky comrades like me, before we can start any configuration we need to make sure that previous configuration do not effect what we are about to do. At boot up of a brand new switch, it always prompts with a qu

I was actually made to write this blog after I end up buying a password protected Cisco 2500 router from Ebay. My room mate collected it and straight away tried to connect it to HyperTerminal as he wanted to test his newly learnt skills from CCNA classes. But more to his disappointment, the router was password protected and it was not until evening when I returned home after work. If you do end up in a similar situation, before you start have your snacks, roll up your sleeves and be prepared for a good 3-4 hrs of command line drill. Alright.. my bad.. it won’t take this long, it’s actually easier than it looks and can only take a max of 2 minutes if you got all the right stuffs with you. And here is how we do it in easy steps: 1) Connect to your router via console. 2) Power reset the Router. 3) When the router boots again, Press "Ctrl + Break” or “Ctrl +Pause”(Hyper-terminal/Putty). Pause/Break is actually the same key. And make sure to do this with in within 60 sec. And if

Understanding Physical Indicators on Cisco Switch a) System: Indicate primary power supply of the switch b) RPS: Redundant Power Supply, i.e. secondary power supply of the switch. NOTE: “Solid Green” in normal conditions, “Amber” indicates malfunctioning. c) Modes: a. Stat: This mode indicates whether the port is in use or not. b. Util: Shows overall utilisation of the switch resources/power. c. Duplex : Lit up ports that are on “Full Duplex” and ports that are not lit up considered as “half Duplex” mode. d. Speed: Lit up ports with “100 Mbps” and leave it unlit at “10 Mbps”. Getting Connected a) Get a console cable: Fig 1 Console Cable b) Plug the serial end into the back of your PC. c) Plug the RJ-45 into the console port of the switch. Fig 2: Console port d) Get a terminal program - HyperTerminal - PuTTY - Tera Term - Minicom - Securecrt e) Set it to connect via COM port with: - Baud Rate: 9600 - Data Bits: 8 - Parity: None - Stop Bits: 1 - Flow Contro

There is a lot written about networks but most of the times when it comes to Basic questions like "What is a network?"(in regards to information technology), most of us will end up saying "A group of different devices that can intercommunicate in an intelligent manner (of-course you may find some that can only give you a shrug,like me)". When I asked myself all I got were random images of pcs and boxes connected via lines, bolts and clouds. Actually what we should concentrate on is what the network does instead of what the network really is? I still remember asking my high school teacher about this cloud. All I was told was that it's Internet: network of networks. Most of us will be pretty satisfied with the above definition of network but read it again, it tells us about what network is made of, and not what network exactly is. Let's take an example from the latest movie I watched, Shrek: the far away kingdom, where King stamps a letter and give