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1 WAN Technologies
Overview

Presentation_ID © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential 11

WAN Technologies Overview
Purpose of WANs

§ WANs connect LANs
§ WANs are used to connect
remote sites to the
enterprise network.
§ WANs connect home users
to the Internet.
§ Enterprise networks are
using security and privacy
solutions over the Internet
to connect remote sites
and users.

Presentation_ID © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential 12

point-to- multipoint topology where a single interface on the hub router can be shared with multiple spoke routers through the use of virtual interfaces Full Mesh • Full Mesh – Each router has a connection to every other router. All rights reserved. Inc. Cisco Confidential 13 . hub-and-spoke topology by providing a second hub to connect to spoke routers Presentation_ID © 2008 Cisco Systems. Hub-and-Spoke line connection such as T1/E1 • Hub-and-Spoke – A single-homed.WAN Technologies Overview Point-to-Point Purpose of WANs § Common WAN topologies are: • Point-to-Point – Typically a dedicated leased. requires a large number of virtual interfaces • Dual-homed – Provides redundancy for a Dual-Homed single-homed.

Inc. each with its own Distributed Network campus network. and telecommuters. WAN contracts to connect the remote networks are negotiated. the topologies and WAN strategies change: • Small Office – These businesses typically consist of one LAN at one location that connects Campus Network to the Internet through a broadband technology. All rights reserved.to medium-sized business with one location and multiple LANs uses specialized equipment and technologies to connect to the Internet. Presentation_ID © 2008 Cisco Systems. it adds more branch offices. • Branch Networks – As the business grows. • Distributed Network – A multinational business has a network distributed across the globe. • Campus Network – A small. These businesses have complex WAN strategies to securely connect to regional offices. Cisco Confidential 14 .WAN Technologies Overview Purpose of WANs Small Office § As businesses grow. partners. branch offices.

Inc. • Central Office (CO) – local service provider facility or building that connects the CPE to the provider network. • Toll network – all the cabling and equipment inside the WAN provider network. • Data Terminal Equipment (DTE) – connects to the local loop through the DCE.WAN Technologies Overview WAN Operations § WAN operations focus primarily on the physical layer (OSI Layer 1) and the data link layer (OSI Layer 2). • Demarcation Point – separates customer equipment from service provider equipment and is the place where the responsibility for the connection changes from the user to the service provider. • Data Communications Equipment (DCE) – provides an interface to connect subscribers to a communication link on the WAN cloud. All rights reserved. Presentation_ID © 2008 Cisco Systems. mechanical. operational. and functional connections • Layer 2 protocols define how data is encapsulated § WAN Terms include: • Customer Premises Equipment (CPE) – owned by the business or leased from the service provider. • Layer 1 protocols describe how to provide electrical. Cisco Confidential 15 . • Local Loop – cable that connects the CPE to the CO of the service provider (last mile).

• Access server – legacy WAN technology that coordinates dial-in and dial-out user communications. supports multiple interfaces. Cisco Confidential 16 . leased-line signals into frames that the LAN can interpret and vice versa. Inc. All rights reserved. • Broadband modem – used with high-speed DSL or cable Internet service • CSU/DSU – used to convert digital.WAN Technologies Overview WAN Operations § WAN devices include: • Dialup modem – legacy WAN technology that converts digital signals into voice frequencies to be transmitted over the analog lines of the public telephone network. • WAN switch – multiport internetworking device used in service provider networks • Router – provides internetworking and WAN access interface ports to connect to the service provider network • Core router/Multilayer switch – resides within the backbone of the WAN. and forwards IP packets at full line speed Presentation_ID © 2008 Cisco Systems.

WAN Technologies Overview WAN Operations Circuit-Switched § WANs can operate as circuit- switched or packet-switched networks: • Circuit-switched Networks – establish a dedicated circuit between source and destination before the users may Packet-Switched communicate. such as making a telephone call • Packet-Switched Networks – split traffic into packets that are routed over a shared network and do not require a dedicated circuit between source and destination Presentation_ID © 2008 Cisco Systems. Cisco Confidential 17 . Inc. All rights reserved.

All rights reserved. 1. Cisco Confidential 18 . Inc.2 Selecting a WAN Technology Presentation_ID © 2008 Cisco Systems.

§ Public WAN Infrastructure • WAN access is achieved through the Internet using broadband connections. Cisco Confidential 19 . Inc. Presentation_ID © 2008 Cisco Systems.Selecting a WAN Technology WAN Services Two way that a business can get WAN access: § Private WAN Infrastructure • The business negotiates for dedicated or switched WAN access with a service provider. All rights reserved. VPNs secure the connections.

Cisco Confidential 20 . Presentation_ID © 2008 Cisco Systems.) This topology illustrates some of these WAN access technologies. Inc. All rights reserved.Selecting a WAN Technology WAN Services (cont.

Selecting a WAN Technology Private WAN Infrastructures Dialup Advantages: Disadvantages: § Simplicity § Cost § Quality § Limited flexibility § Availability Presentation_ID © 2008 Cisco Systems. Cisco Confidential 21 . Inc. All rights reserved.

Cisco Confidential 22 .) Sample ISDN Topology ISDN ISDN BRI ISDN PRI Presentation_ID © 2008 Cisco Systems.Selecting a WAN Technology Private WAN Infrastructures (Cont. All rights reserved. Inc.

Cisco Confidential 23 . § PVCs and DLCIs ensure bidirectional communication from one DTE device to another. All rights reserved. § R1 uses DLCI 102 to reach R2 while R2 uses DLCI 201 to reach R1.Selecting a WAN Technology Private WAN Infrastructures (Cont. § PVCs are uniquely identified by a data-link connection identifier (DLCI). Presentation_ID © 2008 Cisco Systems. Inc.) Frame Relay § PVCs carry both voice and data traffic.

Cisco Confidential 24 . All rights reserved. rather than on a frame-based architecture.Selecting a WAN Technology Private WAN Infrastructures (Cont. Presentation_ID © 2008 Cisco Systems.) ATM Built on a cell-based architecture. Inc. ATM cells are always a fixed length of 53 bytes.

Ethernet over MPLS Note: Commonly used to replace the (EoMPLS).Selecting a WAN Technology Private WAN Infrastructures (Cont. Cisco Confidential 25 . § Known as Metropolitan Ethernet (MetroE). and Virtual Private traditional Frame Relay and ATM WAN LAN Service (VPLS). Presentation_ID © 2008 Cisco Systems. Inc.) Ethernet WAN Features and Benefits of Ethernet WAN include: § Reduced expenses and administration § Easy integration with existing networks § Enhanced business productivity § Service providers now offer Ethernet WAN service using fiber-optic cabling. All rights reserved. links.

Cisco Confidential 26 . All rights reserved.Selecting a WAN Technology Private WAN Infrastructures (Cont. Inc. based on short path labels rather than IP network addresses. Presentation_ID © 2008 Cisco Systems.) MPLS Multiprotocol Label Switching (MPLS) is a multiprotocol high-performance WAN technology that directs data from one router to the next.

a solution that creates a private WAN using satellite communications. All rights reserved. Presentation_ID © 2008 Cisco Systems.) VSAT Very small aperture terminal (VSAT) .Selecting a WAN Technology Private WAN Infrastructures (Cont. Cisco Confidential 27 . Inc.

Presentation_ID © 2008 Cisco Systems. Inc. All rights reserved. and provides IP services to subscribers. which is transmitted to the central office.Selecting a WAN Technology Public WAN Infrastructures DSL § Always-on connection technology that uses existing twisted-pair telephone lines to transport high- bandwidth data. Cisco Confidential 28 . § A DSL modem converts an Ethernet signal from the user device to a DSL signal.

§ Cable modems provide an always- on connection and a simple installation. Inc. Presentation_ID © 2008 Cisco Systems.Selecting a WAN Technology Public WAN Infrastructures (Cont.) Cable § Network access is available from some cable television networks. All rights reserved. Cisco Confidential 29 .

Presentation_ID © 2008 Cisco Systems. Inc. § Satellite Internet .Selecting a WAN Technology Public WAN Infrastructures (Cont.) Wireless New developments in broadband wireless technology: § Municipal Wi-Fi – Many cities have begun setting up municipal wireless § WiMAX – Worldwide Interoperability for Microwave Access (WiMAX) is a new technology that is just beginning to come into use. All rights reserved. Cisco Confidential 30 .Typically used by rural users where cable and DSL are not available.

All rights reserved. § Long-Term Evolution (LTE) – A newer and faster technology. Presentation_ID © 2008 Cisco Systems.) 3G/4G Common cellular industry terms include: § 3G/4G Wireless – Abbreviation for 3rd generation and 4th generation cellular access.Selecting a WAN Technology Public WAN Infrastructures (Cont. considered to be part of the 4th generation (4G) technology. Inc. These technologies support wireless Internet access. Cisco Confidential 31 .

All rights reserved.Selecting a WAN Technology Public WAN Infrastructures (Cont. § Benefits: • Cost savings • Security • Scalability Remote-Access • Compatibility with broadband technology § Two types of VPN: • Site-to-site VPNs • Remote-access VPNs Presentation_ID © 2008 Cisco Systems.) § Public WANs rely on VPNs for Site-to-Site securing data between private networks as it crosses a public network. Inc. Cisco Confidential 32 . such as the Internet.

All rights reserved.Selecting a WAN Technology Selecting WAN Services Answer the following questions when choosing a WAN Connection: Presentation_ID © 2008 Cisco Systems. Inc. Cisco Confidential 33 .

All rights reserved. Cisco Confidential 34 . Inc.3 Summary Presentation_ID © 2008 Cisco Systems. 1.

§ Permanent. Cisco Confidential 35 . § Private WAN connections include: § Public WAN connections include: Dialup DSL ISDN Cable Frame Relay Wireless ATM Cellular Metro Ethernet MPLS VSAT § Security over public infrastructure connections can be provided by using remote-access or site-to-site Virtual Private Networks (VPNs).Chapter Summary Summary § WAN access standards operate at Layers 1 and 2 of the OSI model. Presentation_ID © 2008 Cisco Systems. All rights reserved. Inc. dedicated point-to-point connections are provided by using leased lines.

Inc.Presentation_ID © 2008 Cisco Systems. Cisco Confidential 36 . All rights reserved.

Cisco Confidential 37 . Inc. All rights reserved.Presentation_ID © 2008 Cisco Systems.