1.

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

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

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

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

• 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. leased-line signals into frames that the LAN can interpret and vice versa. supports multiple interfaces. Inc. All rights reserved. • 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. Cisco Confidential 16 .

All rights reserved. Cisco Confidential 17 . 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. 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.

Inc. 1. All rights reserved. Cisco Confidential 18 .2 Selecting a WAN Technology 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. VPNs secure the connections. Inc. All rights reserved. Cisco Confidential 19 . § Public WAN Infrastructure • WAN access is achieved through the Internet using broadband connections. Presentation_ID © 2008 Cisco Systems.

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

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

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

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

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

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

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

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

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

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

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

Selecting a WAN Technology Public WAN Infrastructures (Cont. All rights reserved. Cisco Confidential 31 . Inc. These technologies support wireless Internet access. considered to be part of the 4th generation (4G) 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. § Long-Term Evolution (LTE) – A newer and faster technology.

Selecting a WAN Technology Public WAN Infrastructures (Cont. All rights reserved.) § Public WANs rely on VPNs for Site-to-Site securing data between private networks as it crosses a public network. Cisco Confidential 32 . Inc. § 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. 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. 1. Inc.3 Summary Presentation_ID © 2008 Cisco Systems. Cisco Confidential 34 .

Cisco Confidential 35 . dedicated point-to-point connections are provided by using leased lines. Presentation_ID © 2008 Cisco Systems. All rights reserved.Chapter Summary Summary § WAN access standards operate at Layers 1 and 2 of the OSI model. § 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). § Permanent. Inc.

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

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