1© 2004, Cisco Systems, Inc. All rights reserved.

WAN Technologies Based on

CCNA 4 v3.1 SlidesCompiled & modified by C. Pham

222© 2004, Cisco Systems, Inc. All rights reserved.

Wide-area Networks (WANs)

333© 2004, Cisco Systems, Inc. All rights reserved.

Metropolitan-Area Network (MANs)

444© 2004, Cisco Systems, Inc. All rights reserved.

Path Determination

555© 2004, Cisco Systems, Inc. All rights reserved.

Internetworking

• Any internetwork must include the following:Consistent end-to-end addressingAddresses that represent network topologiesBest path selectionDynamic or static routingSwitching

666© 2004, Cisco Systems, Inc. All rights reserved.

Router: core of WAN technologies

• Routers send packets from oneinterface/network to another

©cisco

777© 2004, Cisco Systems, Inc. All rights reserved.

WAN Topology

Star Topology Full-Mesh Topology

Partial-Mesh Topology

888© 2004, Cisco Systems, Inc. All rights reserved.

Router Internal Components

999© 2004, Cisco Systems, Inc. All rights reserved.

Router Internal Components

101010© 2004, Cisco Systems, Inc. All rights reserved.

Internal Components of a 2600 Router

111111© 2004, Cisco Systems, Inc. All rights reserved.

External Connections on a 2600 Router

121212© 2004, Cisco Systems, Inc. All rights reserved.

Router External Connections

131313© 2004, Cisco Systems, Inc. All rights reserved.

Computer or Terminal ConsoleConnection

141414© 2004, Cisco Systems, Inc. All rights reserved.

Modem Connection to Console orAuxiliary Port

151515© 2004, Cisco Systems, Inc. All rights reserved.

WAN Technology

161616© 2004, Cisco Systems, Inc. All rights reserved.

WAN Service Providers

171717© 2004, Cisco Systems, Inc. All rights reserved.

Physical Layer: WANs

181818© 2004, Cisco Systems, Inc. All rights reserved.

WAN Types

191919© 2004, Cisco Systems, Inc. All rights reserved.

Router Serial WAN Connectors

202020© 2004, Cisco Systems, Inc. All rights reserved.

DCE Serial Connections

212121© 2004, Cisco Systems, Inc. All rights reserved.

WAN Line Types and Bandwidth

222222© 2004, Cisco Systems, Inc. All rights reserved.

CSU/DSU

Channel Service Unit/Data Service Unit.

232323© 2004, Cisco Systems, Inc. All rights reserved.

Modem Transmission

242424© 2004, Cisco Systems, Inc. All rights reserved.

WAN Standards

252525© 2004, Cisco Systems, Inc. All rights reserved.

WAN Encapsulation

262626© 2004, Cisco Systems, Inc. All rights reserved.

WAN Data-Link Protocols

272727© 2004, Cisco Systems, Inc. All rights reserved.

Circuit Switching

282828© 2004, Cisco Systems, Inc. All rights reserved.

Packet Switching

292929© 2004, Cisco Systems, Inc. All rights reserved.

WAN Link Options

303030© 2004, Cisco Systems, Inc. All rights reserved.

WAN Link Options

313131© 2004, Cisco Systems, Inc. All rights reserved.

Analog Dialup

323232© 2004, Cisco Systems, Inc. All rights reserved.

ISDN

333333© 2004, Cisco Systems, Inc. All rights reserved.

ISDN

Router withstandard serialinterface,connected to aterminal adapter

Router with nativeISDN BRI U or S/Tinterface or PRI

343434© 2004, Cisco Systems, Inc. All rights reserved.

Leased Line

• Leased lines are not only used to provide directpoint-to-point connections between EnterpriseLANS, they can also be used to connectindividual branches to a packet switchednetwork.

353535© 2004, Cisco Systems, Inc. All rights reserved.

WAN with X.25

• X.25 provides a low bit rate,shared-variable capacity thatmay either be switched orpermanent

363636© 2004, 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. This leads to

reduced latency.• Frame Relay provides permanent shared medium

bandwidth connectivity that carries both voice and datatraffic.

373737© 2004, Cisco Systems, Inc. All rights reserved.

ATM

• Asynchronous Transfer Mode (ATM) is atechnology capable of transferring voice, video,and data through private and public networks.

• It is built on a cell based architecture rather thanon a frame-based architecture.

383838© 2004, Cisco Systems, Inc. All rights reserved.

DSL

• DSL uses existing twisted-pair telephone lines totransport high-bandwidth data

• DSL service is considered broadband, as it usesmultiple frequencies within the same physicalmedium to transmit data

393939© 2004, Cisco Systems, Inc. All rights reserved.

ADSL Technology

Splitter

• The local loop connects the splitter to the DSLAM• DSLAM connected to ISP using ATM technology• Voice and data use separate frequency ranges

(voice 0-4Khz, data 20Khx – 1Mhz)

404040© 2004, Cisco Systems, Inc. All rights reserved.

Cable Modem

• Enhanced Cable Modems enable two-way. High speed data transmissionsusing the same coaxial lines thattransmit cable television.

414141© 2004, Cisco Systems, Inc. All rights reserved.

Cable Data Network Architecture

424242© 2004, Cisco Systems, Inc. All rights reserved.

Modern WAN

434343© 2004, Cisco Systems, Inc. All rights reserved.

WANs Operate at the Lower ThreeLevels of the OSI Model

444444© 2004, Cisco Systems, Inc. All rights reserved.

Comparing WAN Traffic Types

454545© 2004, Cisco Systems, Inc. All rights reserved.

Steps In WAN Design

464646© 2004, Cisco Systems, Inc. All rights reserved.

Three-Layer Design Model

• The links connecting the various sites in anarea that provide access to the enterprisenetwork are called the access links oraccess layer of the WAN.

• Traffic between areas is distributed by thedistribution links, and is moved onto thecore links for transfer to other regions,when necessary.

474747© 2004, Cisco Systems, Inc. All rights reserved.

Advantages of the Hierarchical Approach

• Scalability: networks can grow without sacrificingcontrol or manageability

• Ease of Implementation: clear functionality at eachlayer

• Ease of troubleshooting: Isolation of problems in thenetwork is easier

• Predicatability network modelling and caapacityplannng easier

• Protocol Support: mixing current and futureapplications and protocols is easier

• Manageability: all the above improve themanageability of the network

484848© 2004, Cisco Systems, Inc. All rights reserved.

Internet for WAN Connectivity

494949© 2004, Cisco Systems, Inc. All rights reserved.

One-Layer Hierarchy

505050© 2004, Cisco Systems, Inc. All rights reserved.

Using the Internet as an Enterprise WAN

• Enterprise WANs will haveconnections to the Internet.

• This poses security problems but also provides analternative for inter-branch traffic.

• VPN technologies can solve security issues

515151© 2004, Cisco Systems, Inc. All rights reserved.

TCP/IP Model

525252© 2004, Cisco Systems, Inc. All rights reserved.

Encapsulation

535353© 2004, Cisco Systems, Inc. All rights reserved.

Summary