1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 2 Module 1 WANs and Routers

222 © 2003, Cisco Systems, Inc. All rights reserved. Objectives Upon completion of this module, the student will be able to perform tasks related to the following: WANs Routers

333 © 2003, Cisco Systems, Inc. All rights reserved. Introduction to WANs A wide-area network (WAN) is a data communications network spanning a large geographic area such as a state, province, or country. They use the services of carriers. A WAN operates at the physical layer and the data link layer of the OSI reference model. It interconnects LANs that are usually separated by large geographic areas.

444 © 2003, Cisco Systems, Inc. All rights reserved. Introduction to WANs WAN data link protocols describe how frames are carried between systems on a single data link. They include protocols designed to operate over dedicated point-to-point, multipoint, and multi-access switched services such as Frame Relay.

555 © 2003, Cisco Systems, Inc. All rights reserved. WAN Devices

666 © 2003, Cisco Systems, Inc. All rights reserved. WAN Services

777 © 2003, Cisco Systems, Inc. All rights reserved. Data Link Encapsulations

888 © 2003, Cisco Systems, Inc. All rights reserved. Introduction to Routers in a WAN Routers connect and allow communication between two networks and determine the best path for data to travel through the connected networks. Routers need the Internetwork Operating System software (IOS) to run configuration files. The main internal components of the router are random access memory (RAM), nonvolatile random-access memory (NVRAM), flash memory, read-only memory (ROM), and interfaces.

999 © 2003, Cisco Systems, Inc. All rights reserved. RAM Stores routing tables Holds ARP cache and fast-switching cache Performs packet buffering (shared RAM) Maintains packet-hold queues Provides temporary memory for the configuration file of the router while the router is powered on Loses content when router is powered down or restarted

10 © 2003, Cisco Systems, Inc. All rights reserved. NVRAM Provides storage for the startup configuration file Retains content when router is powered down or restarted

11 © 2003, Cisco Systems, Inc. All rights reserved. Flash Memory Holds the operating system image (IOS) Allows software to be updated without removing and replacing chips on the processor Retains content when router is powered down or restarted Can store multiple versions of IOS software Is a type of electronically erasable, programmable ROM (EEPROM)

12 © 2003, Cisco Systems, Inc. All rights reserved. ROM Maintains instruction for power-on self test (POST) diagnostics Stores bootstrap program and basic operating system software Requires replacing pluggable chips on the motherboard for software upgrades

13 © 2003, Cisco Systems, Inc. All rights reserved. Interfaces Connect router to network for frame entry and exit Can be on the motherboard or on a separate module

14 © 2003, Cisco Systems, Inc. All rights reserved. Router LANs and WANs While a router can be used to segment LANs, its major use is as a WAN device. Routers have both LAN and WAN interfaces WAN technologies are frequently used to connect routers and these routers communicate with each other by WAN connections.

15 © 2003, Cisco Systems, Inc. All rights reserved. Router LANs and WANs

16 © 2003, Cisco Systems, Inc. All rights reserved. Router LANs and WANs Routers are the backbone devices of large intranets and of the Internet.

17 © 2003, Cisco Systems, Inc. All rights reserved. Router LANs and WANs Two main functions of a router are the selection of best path and the switching of frames to the proper interface. Routers accomplish this by building routing tables and exchanging network information with other routers.

18 © 2003, Cisco Systems, Inc. All rights reserved. Segmentation with Routers

19 © 2003, Cisco Systems, Inc. All rights reserved. WAN Physical Layer

20 © 2003, Cisco Systems, Inc. All rights reserved. WAN Data Link Layer Protocols

21 © 2003, Cisco Systems, Inc. All rights reserved. WAN Standards and Protocols WAN physical layer standards and protocols: EIA/TIA-232 EIA/TIA-449 V.24 V.35 X.21 G.703 EIA-530 ISDN T1, T3, E1, and E3 xDSL SONET WAN data link layer standards and protocols: 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

22 © 2003, Cisco Systems, Inc. All rights reserved. Internal Components of a 2600 Router

23 © 2003, Cisco Systems, Inc. All rights reserved. External Connections on a 2600 Router

24 © 2003, Cisco Systems, Inc. All rights reserved. Router External Connections

25 © 2003, Cisco Systems, Inc. All rights reserved. Computer or Terminal Console Connection

26 © 2003, Cisco Systems, Inc. All rights reserved. Modem Connection to Console or Auxiliary Port

27 © 2003, Cisco Systems, Inc. All rights reserved. Connecting Console Interfaces 1.Configure terminal emulation software on the PC for the following: The appropriate com port 9600 baud 8 data bits 1 stop bit No parity No flow control 2.Connect a rollover cable to the router console port (RJ-45 connector). 3.Connect the other end of the rollover cable to the RJ- 45 to DB-9 adapter 4.Attach the female DB-9 adapter to a PC.

28 © 2003, Cisco Systems, Inc. All rights reserved. Connecting Router LAN Interfaces A router is usually connected to a LAN through an Ethernet or Fast Ethernet interface. The router is a host that communicates with the LAN through a hub or a switch. A straight-through cable is used to make this connection. A 10BASE-TX or 100BASE-TX router interface requires Category 5, or better, unshielded twisted-pair (UTP) cable, regardless of the router type

29 © 2003, Cisco Systems, Inc. All rights reserved. Connecting Router Interfaces

30 © 2003, Cisco Systems, Inc. All rights reserved. Router Serial WAN Connectors

31 © 2003, Cisco Systems, Inc. All rights reserved. Router Serial WAN Connectors

32 © 2003, Cisco Systems, Inc. All rights reserved. DCE Serial Connections

33 © 2003, Cisco Systems, Inc. All rights reserved. Summary