The Internal components of a cisco Router and Switch

The Internal components of a cisco Router and Switch Unless you happen to ve rally savvy about the inner and oute workings of all your car's systems and its machinery and how all of that technology works togthers, you'll take it to someone who does know how to keep it maintained, out what's wrong when it stpis running, and get it up and running again. It's the samne deal with cisco nerworking device you need to know all about their major compinents,pieces, and parts as well as what they all do and why and how they all work together to make a network work. The more solid your knowlwdge, the more expert you are about these thigs and the better equipped you'll be to configure and troubleshoot a cisco internerwork, Toward that goal, study for and introductory description of a cisco routers major components. The Roter and switch Boot sequence when a cisco device boots up, it performs a series of steps, called th boot sequence, to test the hardware and load the necessary software. The boot sequence comprices the following steps: 1. The IOS device performs a POST, which tests the hardware to verify that all components of the device are present and operational. The post takes stock of the different interfaces on the switch or router, nand it's stored in and runs from read-only memory ROM. The bootstrap in ROM then locates and loass the cisco IOS software by excuting programs responsible for fiunging where each IOS program is located, Once the are found, it then loads the proper filoes. By default, the IOS software is loaded from fash memory in all cisco devices. 2.The IOS software then looks for a valid configuration file stored in NVRAM . This file is called srarup-config and will be present only if and sdministrator has copied the running-config file into NVRM. If a starup-config file is found in NVRAM , the router or switch will copy it, place it in RAM, and name the file the running-config. The device eill use this file to run, and the router/switch ahoukd now be operational. If no startup-config file is found in NVRM, the router/ switch should now be operational. If no starup-config file is found in NVRM, the router/switch reacts by broadcasting out any interface that detects carrier detect to locate a TFTP host in its search for a configuration. When that fails, which it typically does, the device eill begin the setup mide configuration process. Most people don't even ralize th device has attempted this process!