1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 4 v3.0 Module 2 WAN Technologies Cisco Networking Academy

222 © 2003, Cisco Systems, Inc. All rights reserved. Objectives WAN Technologies Overview WAN Technologies WAN Design

333 © 2003, Cisco Systems, Inc. All rights reserved. WAN Technology (Phone Company) “Last Mile”

444 © 2003, Cisco Systems, Inc. All rights reserved. WAN Service Providers POP T1

555 © 2003, Cisco Systems, Inc. All rights reserved. WAN Authorities (ITU-T), formerly the (CCITT) (ISO) International Organization for Standardization (IETF) Internet Engineering Task Force (EIA) Electronic Industries Association

666 © 2003, Cisco Systems, Inc. All rights reserved. Physical Layer: WANs Clock Signal Interface Types

777 © 2003, Cisco Systems, Inc. All rights reserved. WAN Line Types and Bandwidth

888 © 2003, Cisco Systems, Inc. All rights reserved. WAN Devices (Access Server) (Console Server)

999 © 2003, Cisco Systems, Inc. All rights reserved. CSU/DSU Channel Service Unit/ Digital Service Unit T1 External CSU/DSU

10 © 2003, Cisco Systems, Inc. All rights reserved. Modem Transmission

11 © 2003, Cisco Systems, Inc. All rights reserved. Circuit Switching Circuit is created for duration of the call and torn down after call is over.

12 © 2003, Cisco Systems, Inc. All rights reserved. Packet Switching

13 © 2003, Cisco Systems, Inc. All rights reserved. WAN Encapsulation – Layer 2

14 © 2003, Cisco Systems, Inc. All rights reserved. WAN Data-Link Protocols – Layer 2

15 © 2003, Cisco Systems, Inc. All rights reserved. HDLC High-Level Data Link Control (HDLC) - An ISO standard. HDLC might not be compatible between different vendors because of the way each vendor has chosen to implement it. HDLC supports both point-to-point and multipoint configurations. Cisco uses its own proprietary implementation of HDLC as the default encapsulation on all serial interfaces. –HDLC was first developed by IBM

16 © 2003, Cisco Systems, Inc. All rights reserved. Integrated Services Digital Network (ISDN) Basic Rate Interface Primary Rate Interface

17 © 2003, Cisco Systems, Inc. All rights reserved. ISDN Integrated Services Digital Network (ISDN) A set of digital services that transmits voice and data over existing phone lines. ISDN was the phone companies attempt at creating an all digital phone system. ISDN is still popular for dedicated video, voice and remote sites where DSL is not available.

18 © 2003, Cisco Systems, Inc. All rights reserved. ISDN 2503 or w/ WIC1-BU

19 © 2003, Cisco Systems, Inc. All rights reserved. Leased Line Leased lines are not only used to provide direct point-to-point connections between Enterprise LANS, they can also be used to connect individual branches to a packet switched network.

20 © 2003, Cisco Systems, Inc. All rights reserved. WAN with X.25 X.25 provides a low bit rate, shared-variable capacity that may either be switched (SVC) or permanent (PVC) VC = Virtual Circuit

21 © 2003, Cisco Systems, Inc. All rights reserved. Frame Relay Frame Relay - By using a simplified framing with no error correction mechanisms over high-quality digital facilities, Frame Relay can transmit data very rapidly, compared to these other WAN protocols. –Frame Relay depends on upper layer protocols such as TCP to take care of lost data Frame Relay is the successor to X.25 and is designed to run over high speed fiber as well as copper.

22 © 2003, Cisco Systems, Inc. All rights reserved. Frame Relay Most Frame Relay connections are based on PVCs rather than SVCs. It implements no error or flow control. Frame Relay provides permanent shared medium bandwidth connectivity that carries both voice and data traffic.

23 © 2003, Cisco Systems, Inc. All rights reserved. ATM Asynchronous Transfer Mode (ATM) is a technology capable of transferring voice, video, and data through private and public networks. It is built on a 53-byte cell based architecture rather than on a frame-based architecture.

24 © 2003, Cisco Systems, Inc. All rights reserved. Point-to-Point Protocol Point-to-Point Protocol (PPP) - Described by RFC 1661, two standards developed by the IETF. PPP contains a protocol field to identify the network-layer protocol. PPP allows for dynamic address allocation and authentication. –PAP – Password Authentication Protocol –CHAP – Challenge Handshake Authentication Protocol

25 © 2003, Cisco Systems, Inc. All rights reserved. Broadband Broadband refers to a technique which uses multiple frequencies within the same physical medium to transmit data. Generally speaking, Broadband refers to cable modem and DSL modem technologies for the home user.

26 © 2003, Cisco Systems, Inc. All rights reserved. DSL Do you get these download speeds??? Digital Subscriber Line (DSL) technology is a broadband technology that uses existing twisted-pair telephone lines to transport high-bandwidth data to service subscribers.

27 © 2003, Cisco Systems, Inc. All rights reserved. xDSL The term xDSL covers a number of similar yet competing forms of DSL technologies: 1.Asymmetric DSL (ADSL) 2.Symmetric DSL (SDSL) 3.High Bit Rate DSL (HDSL) 4.ISDN (like) DSL (IDSL) 5.Rate Adaptive DSL (RADSL) 6.Consumer DSL (CDSL), also called DSL-lite or G.lite

28 © 2003, Cisco Systems, Inc. All rights reserved. ADSL Technology

29 © 2003, Cisco Systems, Inc. All rights reserved. Cable Modem Enhanced Cable Modems enable two- way, high speed data transmissions using the same coaxial lines that transmit cable television.

30 © 2003, Cisco Systems, Inc. All rights reserved. Modern WAN

31 © 2003, Cisco Systems, Inc. All rights reserved. Star Topology – Hub and Spoke

32 © 2003, Cisco Systems, Inc. All rights reserved. Full-Mesh Topology

33 © 2003, Cisco Systems, Inc. All rights reserved. Partial-Mesh Topology

34 © 2003, Cisco Systems, Inc. All rights reserved. Three-Layer Design Model The links connecting the various sites in an area that provide access to the enterprise network are called the access links or access layer of the WAN. Traffic between areas is distributed by the distribution links, and is moved onto the core links for transfer to other regions, when necessary.

35 © 2003, Cisco Systems, Inc. All rights reserved. Internet for WAN Connectivity

36 © 2003, Cisco Systems, Inc. All rights reserved. One-Layer Hierarchy