Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Semester 4, v Chapter 2: WANs Curriculum Review Youngstown State University Cisco Regional Academy

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Disclaimer  This presentation is intended for review purposes by Cisco Networking Academy Program teachers and students only.  This presentation is not a substitute for careful study of the Cisco Academy curriculum.  Most of the text and graphics have been copied directly from the on-line curriculum, and remain the copyrighted property of Cisco Systems.  CCNA objectives are used for reviews.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Contents  Part 1: WAN Technology  Part 2: WAN Devices  Part 3: WANs and the OSI Model  Part 4: WAN Encapsulation  Part 5: WAN Link Options

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Chapter Learning Objectives  You will be able to: –Define a WAN. –Describe the types of available WAN services. –Describe WAN devices and their interfaces. –Explain the OSI layers of WAN operation. –Describe PPP and HDLC WAN encapsulations. –Describe common WAN link options.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Part 1 WAN Technology

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program  WAN: –Data network that operates beyond a LAN's geographic scope. –Subscribes to an outside WAN service provider, such as a regional Bell operating company (RBOC) to use WAN carrier services. –Uses data links, such as Integrated Services Digital Network (ISDN) and Frame Relay, that are provided by carrier services. WAN – Wide Area Network

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Technologies  WAN technologies function at the three lowest layers of the OSI reference model: –network, –data link, –physical.  The main focus is on the physical and data link layers!

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Services  Examples of WAN Services are: –ISDN Integrated Services Digital Network. Permits telephone networks to carry data, voice, and other traffic over copper lines. –Frame Relay Industry-standard, switched data link layer protocol. Handles multiple virtual circuits using HDLC encapsulation between connected devices.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Service Types  Time-division multiplexing (TDM) –Information from many sources has bandwidth allocation on a single medium. –Multiplexed traffic in fixed time slots, avoids congested facilities. –Used by basic telephone service and ISDN.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Service Types  Call setup –Sets up and clears calls between users.  Frame Relay –Information contained in frames shares bandwidth with other WAN Frame Relay subscribers.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Service Provider Terms  Provider gives connection and equipment requirements used to receive services.  Commonly used terms with WAN services: –Customer premises equipment (CPE) Devices physically located at the subscriber's site. Devices may be owned by the subscriber and/or leased from the service provider. –Demarcation (demarc) The point at which the CPE ends and the local loop portion of the service begins. Often occurs at the POP of the building.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Service Provider Terms –Local loop (or "last-mile") Cabling (usually copper) that extends from the demarc to the WAN service provider's central office. –CO switch A switching facility that provides the nearest point of presence for the provider's WAN service. –Toll network The collective switches and facilities (called trunks) inside the WAN provider's cloud.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Subscriber to Provider Interface  The key interface in the customer site is between the Data Terminal Equipment (DTE) and the Data Circuit-terminating Equipment (DCE). –The DTE device is usually the customer router. –The DCE device converts the user data from the DTE into an acceptable WAN service. CSU/DSU – Channel Service Unit/Data Service Unit Modem TA NT1 -Terminal Adapter/ Network Termination 1

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Virtual Circuits  A virtual circuit is a logical circuit created to ensure reliable communication between two network devices. –Switched Virtual Circuits (SVCs) Dynamically established on demand and terminated when transmission is complete. –Permanent Virtual Circuits (PVCs) A permanently established virtual circuit that consists of one mode: data transfer. Frame Relay and X.25

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Data Lines  WAN links can be ordered from a provider at various speeds stated in bits per second (bps) capacity. –T Mbps (United States) –E Mbps (Europe)  Special note: –In countries that use T1 lines, ISDN service utilizes 23 B-channels and 1 D-channel for a total bandwidth of Mbps. –In countries using E1 lines, ISDN service provides transmission of digital data over 30 B-channels (64 Kbps) and one D-channel (64 Kbps) plus one framing channel (64 Kbps) for a total bandwidth of Mbps.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Part 2 WAN Devices

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program  Routers –LAN and WAN interface ports.  WAN switches, –Connect to WAN bandwidth for voice, data, and video. –Modems, Interpret digital and analog signals. Interfaces voice-grade services. Include CSUs/ DSUs and TA/NT1 devices that interface ISDN services. Wan Devices

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Leased Line Connections  CSU/DSU adapts the physical interface on a DTE device to the interface of a DCE device in a switched-carrier network.  CSUs/DSUs are sometimes integrated in the router box.  A WAN switch is NOT always necessary!

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Part 3 WANs and the OSI Model

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Physical Layer  WAN physical-layer protocols describe: –The electrical, mechanical, operational, and functional connections for WAN services. –Also the interface between the DTE and the DCE.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Data Link Layer  WAN data link layer defines: –How data is encapsulated for transmission. –How frames are carried between systems on a single data path.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Data Link Layer Protocols  Frame Relay –Simplified encapsulation with no error correction using high-quality digital facilities.  Point-to-Point Protocol (PPP)  ISDN –Digital services over existing phone lines for voice and data.  High-Level Data Link Control (HDLC) –An ISO standard. Supports both point-to-point and multipoint configurations. –Vendor specific implementation.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Part 4 WAN Encapsulation

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program  Each WAN connection uses a Layer 2 protocol to encapsulate traffic while it is crossing the WAN link. –All serial line encapsulations share a common frame format. –Most common point-to-point WAN encapsulations are HDLC and PPP. WAN Frame Encapsulation

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program PPP Encapsulation  PPP can: –Check for link quality during connection establishment. –Support authentication through: Password Authentication Protocol (PAP). Challenge Handshake Authentication Protocol (CHAP).

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program HDLC Encapsulation  Derived from the Synchronous Data Link Control (SDLC) encapsulation protocol. –HDLC is Cisco's default for serial lines. –Only point-to-point connections are allowed.  HDLC framing is not compatible with other vendors' equipment. –Use PPP with devices that are not running Cisco IOS software!

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Part 5 WAN Link Options

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program WAN Link Line Options  Two basic line options are: –Dedicated –Switched

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Dedicated Lines  Provide dedicated, full time service from WAN provider via serial link.  Point-to-point link provides a single, pre- established WAN path. –T1 most widely used. –Data, voice, video. –Core WAN or backbone connectivity.  Also called “leased lines.”

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Packet Switched Option  Network devices share a permanent virtual circuit (PVC) with other WAN’s.  Examples are: –X.25 –Frame Relay Access is typically at: –56 kbps, –64 kbps, –or Mbps. Most widely used.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Circuit Switched  Dedicated physical circuit is established on demand only!  Similar to regular telephone service.  Low bandwidth –Modem 28.8 to 56 Kbps –ISDN 64 or 128 Kbps  Dial on Demand Routing (DDR) uses this system. –Dynamically initiates and terminates WAN connectivity as needed.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Summary  WAN –Interconnect LANs that are separated by a large geographic distance. –Provides a data path between routers and the LANs that each router supports. –Devices include WAN switches, modems, and ISDN TAs. –Mainly operates at the OSI physical and data link layers.  Many types of WAN services are available to the WAN subscriber. –Must interface to the provider's service.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program Summary  WAN encapsulation formats include PPP and HDLC encapsulation.  WAN link options include: –Dedicated lines such as point-to-point links, –Packet-switched connections such as Frame Relay, –Circuit-switched connections such as DDR and ISDN.

Robert E. Meyers CCNA, CCAI Youngstown State University Cisco Regional Academy Instructor Cisco Networking Academy Program End