Wide-Area Networks

Wide-Area Networks

1. Introducing Wide-Area Networks

   • Basic Telco Services
     • Switched Analog Circuits for Voice and Data
     • Digital Circuits and Leased Lines
     • Switched Circuits and Circuit Switching
     • The Content-Aware Telco: Packet Switching
   • Using Routers to Send IP Packets over WANs
     • Routers Connect LANs to WANs
     • Encapsulation and Deencapsulation
   • WAN and LAN Topologies
     • Point-to-Point Topologies
     • Hub-and-Spoke Topologies
     • Multipoint Topologies

2. Understanding Leased-Line WANs

   • The Customer Perspective on Physical Leased Lines
     • Distance Limitations
     • Speeds
     • Cabling
     • Channel Service Unit/Data Service Unit
     • Customer Ends of a Leased Line
   • The T-Carrier System and TDM
     • The Challenge: Too Many Trunks Between Sites
     • Making Efficient Use of Trunks with Time-Division Multiplexing
     • TDM Switches and Mapping T1s to T3 Channels
   • T1 and the Role of the CSU/DSU
     • Different Views of Bit Rates: Routers Versus CSU/DSU
     • DS1 (T1) and the T1 Frame
     • Adjusting the Speed Using a CSU/DSU
     • The Router and CSU/DSU on a Full T1 Leased Line
     • The Router and CSU/DSU on Fractional T1 Leased Line
     • Worldwide Variations on T-Carrier Lines
   • Controlling Leased Lines with Data-Link Protocols
     • HDLC
     • Point-to-Point Protocol (PPP)

3. Understanding Packet Switching and Multiaccess WANs

   • Packet Switching Versus TDM
   • Frame Relay
     • Frame Relay Pysical Access Links
     • Frame Relay Virtual Circuit (VC) Concepts
     • Partial Mesh and Full Mesh
     • Frame Relay Forwarding with DLCIs
   • Packet-Switching Services and Beyond