Router

The main components of the router are as follows:

CPU - Central Processing Unit in charge to run the commands in the operating system. Some functions such as dilaukan by the CPU: the system initialization, routing, and control the network interface. Router CPU is a microprocessor.

RAM - RAM is used for routing table information, fast switching cache, which is the road configuration, and set the packet queue. In most routers providing RAM memory space to perform the function of the router. RAM logically divided into main processor memory and memory share the input / output (I / O). Memory share I / O is the share of the router interfaces for storage while the package. The contents of RAM will be lost if the router is switched off or restarted. RAM typically type dynamic random-access memory (DRAM) and can be upgraded by adding a memory module yan called dual in-line memory module (DIMM).
Flash - flash memory used to store the image of the IOS. Normally needed IOS router default of flash. Image can be upgraded by downloading a new image into flash. IOS could be too compressed or not. In most routers to copy the IOS into RAM ditansfer during the booting process. On the other Cisco IOS router may be able to run directly from flash. Installed in a single flash. SIMMs 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 device can be used as EEPROM NVRAM function. On other devices used to as a flash for boot melaukan. The contents of the NVRAM is not lost meskipung router is switched off or restarted.
Bus - Most routers consists of system bus and CPU. system bus used for communication between the CPU and the interface or an additional slot. This bus transfer to and from the packet interface.
CPU bus is used to access storage media components of the router. This bus command and data transfer to or from memory address used.
ROM - ROM used to store permanent code diagnostic startup, which is known as the ROM monitor. The main task is to dignosa ROM hardware during booting and loading the router IOS from flash to RAM. Some routers, ROM can also be used as an alternative boot source. And can be upgraded by removing socketnya chip.
Interface - Interface of the router used to connect the connection to the outside. There are 3 types of interfaces: LAN, Wan and the console or auxiliary (AUX). LAN interface is usually one or several types of ethernet or token ring different. Each controller chip intreface has a function 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. Same with the LAN interface, it also has a controller chip. Wan interface can be either fixed or modular configuration.
Console or AUX port is a serial prot used for the configuration process. It is used as a terminal of the communication port on the computer through a modem.
Power Supply - power supply is used as a resource to operate the components in the router. Some routers may have more than one power supply.

LAN interface connects the router to the LAN media. WAN allows connection connected through the service provider to distant places or to the Internet. Types of connections may be serial or other WAN interface. With the type of the other WAN interface, an, external devices such as CSU is required to connect the router to the local connection service providers. With the type of other WAN, the router may also be connected directly to the service provider.

The function of port management is different from other connections. A common management interface is the console and auxiliary port using the serial ports with EIA-323 is used for asynchronous communication with the port on the computer.

The first time the router is used, no network is configured, so the router can not communicate with other networks. To set up the router to get connected to the network, the initialization and configuration required. It is necessary to roll-over cable is connected between the port management to a computer through terminal software emulating sperti HyperTerminal. After configuration, the router is ready for communication with the network.

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

Connection to the LAN router interface
Generally connected to the router via the LAN interface Ethernet or Fast Ethernet. Router as a host that communicates with the LAN through a hub or switch. In this case a straight-through cable is used. For 10BASE-TX or 100BASE-TX requires Category 5 UTP cable or better.

WAN using a variety of technologies to create data connections in a wide geographic area. Communication via WAN typically uses lease lines from the provider, such as leased lines, circuit-switched and packet-switched.
WAN service type of customer premises equipment (CPE), the router as a DTE that is connected to the service provider through a DCE device typically uses a modem or CSU / DSU. This equipment is used to convert data from the DTE to a service provider supported WAN. And chances are the router interface used is a serial connection.

Conclusion
- WAN is a data communications network that connects users within a geographic area that is very broad.
- Router is a kind of special computer designed for specific functions that are not owned by a desktop computer (PC).

Exercise in the Lab.
Connection to the computer console interface:

Preparation
Console cable required to connect the PC to a Cisco router in order to perform the configuration. So take the following equipment:
- PC with serial interface
- Cisco Router
- Cable roll-over

Step 1 identifies the types of connectors and components.
Look for RJ-45 connector labeled Console on the Cisco Router

Step 2 identifies the computer serial interface (COM 1 or 2)
Look for 9-pin connector or 25-pin Male to read the serial

Step 3 Identify the console cable adapter for
Look for an adapter that connects an RJ-45 connectors to DB-9 or RJ-45 to DB-25 depending on the serial port in your PC, as shown in the picture below.

Step 4 Prepare the cable roll-over
Use the roll-over cable to connect the terminal serial console port router to PC

Step 5 Connect the cable roll-over to the PC
Connect the cable roll-over to the console port of the router through RJ-45 terminal, then connect the other end into the adapter DB-9 or DB-25 depending on the serial port in your PC. As the picture below.

The rules in the WAN Router

Standards and protocols or the main function of the WAN is operating at the physical layer and data link layer. That means another layer 5 is not found in the WAN. In other words, standard and protocol layer 1 and layer 2 WAN different from a standard and protocol layer 1 and layer 2 of the LAN.

WAN physical layer describes the interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE). Generally, DCE is on the provider and the DTE is on the device. In this model, communication through the DTE with the help of a modem or CSU / DSU.
The main function of a router is to send data using a 3-layer address. This process is called routing. Routing occurs at the network layer, or Layer 3. If the WAN operates at Layer 1, 2 and 3, if the router is a device for LAN or WAN? the answer is both.
Router in the WAN is to deliver packets at layer 3, but he also could be used in a LAN. At the time of the router using a standard protocol and physical layer and data link layer it operates as WAN equipment. For example, a router may have to have an ISDN interface that uses PPP encapsulation, and a serial interface that is connected to T1 lines using Frame Relay encapsulation. Router must be able to change the bit stream from a single service type to another type, in this case, T1 and ISDN to modify the data link encapsulation from PPP to Frame Relay.

Below is a list of standards and protocols on the WAN physical layer:
- EIA/TIA-232
- EIA/TIA-449
- V.24
- V.35
- X.21
- G.703
- EIA-530
- ISDN
- T1, T3, E1 and E3
- XDSL
- SONET (OC-3, OC-12, OC-48, OC-192)

Below is a list of standards and protocols on the WAN data link:
- High-level data link control (HDLC)
- Frame Relay
- Point-to-Point Protocol (PPP)
- Synchronous Data Link Control (SDLC)
- Serial Line Internet Protocol (SLIP)
- X.25
- ATM
- LAPB
- LAPD
- LAPF

LAN and WAN routers

Router has a good interface for LAN or WAN. WAN technologies always use a router. WAN router uses to communicate with others. Router is a backbone equipment from large-scale intranet or the Internet. Routers operate at OSI layer 3, made decisions based on network address. Two main functions of the router is to select the best path and the switching of data packets to the destination inetrface. To perform its func

tion, the router always formed roueing table and exchange information on networks with other routers.
Administrators can configure static routing to maintain routing tables. Melaukan basically maintained the preferred routing tables dynamically in the exchange of information about the network with other routers.

For example, if computer X to computer communication with computers Y and Z. As illustrated in the figure 1.6, it requires routing information. Many paths can be taken to reach the computer Y and Z, the router will choose the best path.

Internetwork configuration requires the right things as follows:
- Address end-to-end must be consistent
- Address used in the network topology
- Selection of the best lines
- Dimanis or static routing
- The process of switching

Introducing WAN Router

1.2 Introduction to WAN router

Router is a special computer, a router has the basic components are the same as desktop PCs, routers have the CPU, memory, system bus, and many interface input / output. Routers are designed to perform specific tasks that are not owned by the PC desktop. For example, the router connects and allows communication between two networks and determine the data path through the network connection.
Same with the PC, the router operating system needs to perform its function, namely Internetwork Operating System (IOS) software to run its configuration files. These configurations contain commands and parameters that control the flow of traffic into and out of the router. Routers use routing protocols to determine the best path.
The main components of the router is the random-access memory (RAM), nonvolatile random-access memory (NVRAM), flash memory, read-only memory (ROM) and interfaces.

RAM has the functions and characteristics as follows:
- Save the routing table
- Handling the ARP cache
- Dealing with fast-switching cache
- Handles packet buffering and share RAM
- Handling the queue package
- Provide temporary memory for configuration files when the router works
- Data will be lost when the router is switched off or restart

NVRAM has functions and characteristics as follows:
- Provides storage for the startup configuration file
- Data is still there even though the router is turned off or restart

Flash memory has the functions and characteristics as follows:
- Handling the IOS image
- Providing access to software updates without having to remove the chip on the processor
- Data is still there when the router is turned off or restart
- Can store multiple versions of Cisco IOS software

- It is the kind of Electrically Erasable Programmable Read-only memory (EEPROM)

ROM has the functions and characteristics as follows:
- Handles the commands for power-on diagnostic selt test (POST)
- Save bootstap programs and basic operating system
- Need a chip off the motherboard when you upgrade the software

Interface has the functions and characteristics as follows:
- Connect the router to a network as data packets turnover
- Just being in the motherboard or as a separate module

Router and WAN

Introduction

Wide Area Network (WAN) is a data communications network that connects users in a network that was in a large geographic area. WAN has several important characteristics that distinguishes it from the LAN. In the first lesson in this module will discuss the introduction of WAN technologies and protocols. And also will explain how the similarities and differences between the WAN and LAN.

It is very important to understand the physical layer components in a router. This will increase the knowledge base of information and capabilities that will be required to configure the router and set up the network routing. This module also describes the techniques of the physical connection of various router interfaces.

1. WAN
1.1 Introduction WAN
WAN is a data communication network that is spread on a large geographic area such as provinces or states. WAN always uses transmission facilities provided by telecommunications companies such as telephone service companies.

Characteristics of WAN:
- Connect the equipment that spread to a wide geographic area
- Using public service channels, such as telecommunications companies. PT. Telkom, PT. Indosat, PT. Excelcomindo and others to form a network within the geographic area.
- Using the serial connections to access bandwidth throughout the geographic area.
WAN different from the LAN. Unlike LAN-connected workstation workstations, equipment, terminals and other equipment dalan a building, WAN connecting the data in a wide geographic area. Companies that use the WAN can connect between headquarters and branch offices are located at a distance.
A WAN operates at the physical layer and data link layer of the OSI layer. WAN connects LANs within a large geographic area. WAN capable pertukakaran and frame data packets between the routers and switches.

Here are the tools used in the WAN:
- Router, including internetworking and port-port WAN interface
- Modem, including voice-grade interfaces, channel service units / digital service units (CSU / DSU) that serves T1/E1 interfaces, and the Terminal Adapter / Network Termination 1 (TA / NT 1) as an interface Integrated Services Digital Network (ISDN)
- Server-server dial-in and user-user who does dial out to connect



WAN handling standards:
- International Telecommunication Union-Telecommunication Standardization Sector (ITU-T), the Consultative Committee for International Telegraph and Telephone (CCITT)
- International Prganization for Standardization (ISO)
- International Engineering Task Force (IETF)
- Electronics Industries Association (EIA)

WAN is designed to:
- Operates in the area of the vast geographical
- Ability to provide a serial connection with low cost and low speed or high cost and high speed such as via the ATM or fiber optic
- Ability to provide full-time connection and part-time