Reza's Informatics: Router (Networking)

2. Router

The main components of the router is as follows:

CPU - Central Processing Unit tasked to run commands in the operating system. Some functions such as CPU done by: initiate the system, routing, and control the network interface. CPU router is a microprocessor.

RAM - RAM is used for routing table information, fast switching cache, the current road configuration, and set the packet queue. On most routers provide space RAM memory to run the router. The logic of RAM memory is divided into the main processor and memory share input / output (I / O). Memory share I / O is the interface between the share-interface router for temporary storage package. The contents of RAM will be lost if the router is turned off or restart. RAM type is usually dynamic random-access memory (DRAM) and can be upgraded by adding a memory module called dual in-line memory module (DIMM).

Flash - flash memory used to store the image of ios. Normally requires the router's flash ios default. Image can be upgraded with a download to the new image in flash. Ios can be ter-compressed or not. On most routers to re-copy ios transfer to RAM during the booting process. On the other router ios may be able to run from flash slim. Flash is installed single SIMM slot or a PCMCIA card that can be added or removed during the upgrade flash.

NVRAM - NVRAM used to store the startup configuration. At the same EEPROM devices that can be used as a function of NVRAM. On the other devices used to perform as a flash for booting.

The contents of NVRAM will not be lost even if the router is turned off or restart.

Bus - Most of the router is made up of the system bus and CPU bus. bus system is used for communication between the CPU and the interface or additional slots. This package bus transfer to and from the interface.
CPU bus is used to access components of the media in the router. Bus is the command and data transfer to or from a memory address that is used.

ROM - ROM are used to permanently store code Diagnostic startup, which is known by the name of ROM monitor. ROM is the main task for dignosa router hardware for booting and loading ios from flash to RAM. Some routers, ROM can also be used as an alternative source booting. And can be upgraded with a chip on socket release.

Interface - Interface of the router used to connect the connection to the outside. There are 3 types of interface: LAN, Wan and console or Auxiliary (AUX). LAN interface is usually one or several types of ethernet or token ring different. Each interface has a controller chip that serves to connect the system to the media. LAN interface is usually a fixed or modular configuration.
WAN interfaces such as serial, ISDN and integrated CSU. Interface with the same LAN, it also has a controller chip. Wan interface can be fixed or modular configuration.
Console port or AUX serial Prot is used for the configuration process. It was used as the terminal of the communication port on the computer via modem.

Power Supply - power supply is used as a source of power to operate the components in the router. Some router likely have more than one power supply.

Figure 2.1 Components router

Figure 2.2 Components router

Figure 2.3 Sample Component internal Cisco router 2600

Figure 2.4 Sample Component external Cisco router 2600

LAN interface to connect the router media LAN. WAN allows connection connected through the service provider to the place of the remote or to the Internet. Type of connection may be serial or other WAN interface. WAN interface with the type of the other, a, external devices such as CSU needed to connect the router to connect local service providers. WAN connection type with the other, the router may also be linked directly to the service provider.
Management functions from a different port connection with the other. Management interface that is common console and Auxiliary port using serial ports asynchronous EIA-323 is used for communication with the port on the computer.

Figure 2.5 Connection external

The first time the router is used, no network is configured, so the router can not communicate with other networks. To set up a router that can connect to the network, the initialization and configuration required. So required cable roll-over of management that is connected to the computer through the port terminal emulating software like hyperterminal. After the configuration is done, the router is ready for communication with the network.

Figure 2.6 Computer Connection terminal or console

Below, the steps to connect the PC to the router:
1. Configuration terminal emulation to the PC with the parameters:
- COM port that is used
- Bps: 9600
- Data bits: 8
- No parity
- Stop bit 1
- No flow control
2. Connect the RJ-45 connector cable roll-over to console terminal router
3. Connect the other end to the DB-9 terminal
4. Connect the terminal female DB-9 adapter to the PC

Figure 2.7 Connection to the console or modem port Auxiliary

Figure 2.8 connector Cisco router 2600

Figure 2.9 Connection via terminal console

Figure 2.10 Properties hyperterminal

Interface connection to the LAN router
Generally, the router is connected to the LAN interface via Ethernet or Fast Ethernet. Router as a host to communicate with the LAN through a hub or switch. In this straight-through cable is used. For 10BASE-TX or 100BASE-TX requires UTP cable category 5 or more.

Figure 2.11 router connection to LAN

Figure 2.12 types of connection router cisco 2600 series

WAN use various technologies to create a data connection in a wide geographic area. Communication through WAN usually use lease lines from the provider, for example, Leased line, circuit-switched and packet-switched.

Type WAN services such as customer premises equipment (CPE), the router as a DTE that is connected to the service provider through the DCE equipment generally use a modem or CSU / DSU. This equipment is used to convert data from the DTE to a service provider WAN supported. And it's likely the router interface that is used is the serial connection.