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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

WAN Technologies Overview Point-to-Point Purpose of WANs § Common WAN topologies are: • Point-to-Point – Typically a dedicated leased. Cisco Confidential 13 . hub-and-spoke topology by providing a second hub to connect to spoke routers Presentation_ID © 2008 Cisco Systems. All rights reserved. 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. requires a large number of virtual interfaces • Dual-homed – Provides redundancy for a Dual-Homed single-homed. Hub-and-Spoke line connection such as T1/E1 • Hub-and-Spoke – A single-homed. Inc.

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

• Local Loop – cable that connects the CPE to the CO of the service provider (last mile). • Toll network – all the cabling and equipment inside the WAN provider network. operational. • 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. Inc.WAN Technologies Overview WAN Operations § WAN operations focus primarily on the physical layer (OSI Layer 1) and the data link layer (OSI Layer 2). Presentation_ID © 2008 Cisco Systems. All rights reserved. • Data Communications Equipment (DCE) – provides an interface to connect subscribers to a communication link on the WAN cloud. • Layer 1 protocols describe how to provide electrical. • Central Office (CO) – local service provider facility or building that connects the CPE to the provider network. mechanical. • Data Terminal Equipment (DTE) – connects to the local loop through the DCE. 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. Cisco Confidential 15 .

• Broadband modem – used with high-speed DSL or cable Internet service • CSU/DSU – used to convert digital. • 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.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. All rights reserved. Inc. Cisco Confidential 16 . leased-line signals into frames that the LAN can interpret and vice versa. supports multiple interfaces. • Access server – legacy WAN technology that coordinates dial-in and dial-out user communications. and forwards IP packets at full line speed Presentation_ID © 2008 Cisco Systems.

All rights reserved. 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.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.

Cisco Confidential 18 . Inc. All rights reserved. 1.2 Selecting a WAN Technology Presentation_ID © 2008 Cisco Systems.

All rights reserved. Cisco Confidential 19 .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. Presentation_ID © 2008 Cisco Systems. Inc. § Public WAN Infrastructure • WAN access is achieved through the Internet using broadband connections. VPNs secure the connections.

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

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

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

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

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

and Virtual Private traditional Frame Relay and ATM WAN LAN Service (VPLS). Ethernet over MPLS Note: Commonly used to replace the (EoMPLS). Cisco Confidential 25 .Selecting a WAN Technology Private WAN Infrastructures (Cont. Inc. links.) 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. Presentation_ID © 2008 Cisco Systems. § Known as Metropolitan Ethernet (MetroE).

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

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

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

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

Cisco Confidential 30 . Presentation_ID © 2008 Cisco Systems. Inc.Typically used by rural users where cable and DSL are not available.) 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.Selecting a WAN Technology Public WAN Infrastructures (Cont. § Satellite Internet . All rights reserved.

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

Inc. such as the Internet.) § Public WANs rely on VPNs for Site-to-Site securing data between private networks as it crosses a public network. Cisco Confidential 32 .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. All rights reserved.

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

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

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). Inc. Presentation_ID © 2008 Cisco Systems. dedicated point-to-point connections are provided by using leased lines. All rights reserved. § Permanent.Chapter Summary Summary § WAN access standards operate at Layers 1 and 2 of the OSI model.

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

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