Cisco Hierarchical Internetworking Model: Cisco has defined a hierarchical model known as the hierarchical internetworking model. This model simplifies the task of building a reliable, scalable, and less expensive hierarchical internetwork because rather than focusing on packet construction, it focuses on the three functional areas, or layers, of your network: Core layer: This layer is considered the backbone of the network and includes the high-end switches and high-speed cables such as fiber cables. This layer [...]

Cisco Discovery Protocol (CDP) Cisco Discovery Protocol (CDP) is a Cisco proprietary (layer 2) protocol that provides information about directly connected Cisco routers and switches (if enabled on the switch). CDP messages are not forwarded and, of course, not routed (layer 2). The protocol operates transparently and is enabled by default on all Cisco routers. It can be useful if you are trying to troubleshoot a connectivity problem. If the Data Link layer is operating, [...]

OSI Layer Model: 7 layers of osi model: The International Standards Organization (ISO) developed the Open Systems Interconnection (OSI) Reference Model to define functional communications standards. This reference model is widely used by equipment manufacturers to assure their products will interoperate with products from other vendors. The OSI model describes the functions that are performed in data communications. The model architecture is seven layers those are listed below with each layer defining specific functions. Layer [...]

IOS Commands Router modes Modes Description Router> User mode Router# Privileged mode Router(config)# Global configuration mode Router(config-if)# Interface mode Basic IOS Commands Command Description Syntax Enable Puts you into privileged mode Router>enable Disable Takes you from privileged mode back to user mode Router>disable Config Terminal Puts you in global configuration mode and change the running-config Router#config t Hostname Sets the name of a router Router(config)#hostname R1 Banner Creates a banner for users who log into [...]

Windows interview Questions How do you double-boot a Win 2003 server box? The Boot.ini file is set as read-only, system, and hidden to prevent unwanted editing. To change the Boot.ini timeout and default settings, use the System option in Control Panel from the Advanced tab and select Startup. What do you do if earlier application doesn’t run on Windows Server 2003? When an application that ran on an earlier legacy version of Windows cannot be [...]

Routing And Types of Routing This is the new post on Routing and Types of Routing ,Routing Protocols ,Routing Information Protocol Routing: Routing is the process of forwarding packets from one network to another. All the information needed for a router to forward packets to a hop (router/relay device) can be found in the router’s routing table. Static Routing: Static routing occurs when you manually add routes in each router’s routing table. Static routes are [...]

Physical Layer: Physical Ring Topology: A physical ring is a circular topology. Each device connects directly to the ring or indirectly through an interface device and drop cable. Physical Ring Topology LAN: Star topologies can be nested within other stars to form tree or hierarchical network topologies. In star topologies, electric or electromagnetic signals travel from the networked device, up its drop cable, to the hub. From there the signal is sent to other networked [...]