11 ROUTING IP Chapter 3 Chapter 3: ROUTING IP2 CHAPTER INTRODUCTION Understand the function of a router. Understand the structure of a routing table. Choose between static or dynamic routing on your network. Select, install, and configure the dynamic routing protocol most suitable for your network. Use routers to connect LANs and WANs. Understand the function of a router. Understand the structure of a routing table. Choose between static or dynamic routing on your network. Select, install, and configure the dynamic routing protocol most suitable for your network. Use routers to connect LANs and WANs. Chapter 3: ROUTING IP3 UNDERSTANDING IP ROUTING Routers direct data through the network. Routers connect two networks or two segments on an internetwork. Routers can be used on LANs to provide connectivity between segments, on WANs to provide connectivity between LANs, and on either to provide connectivity to the Internet. Routers direct data through the network. Routers connect two networks or two segments on an internetwork. Routers can be used on LANs to provide connectivity between segments, on WANs to provide connectivity between LANs, and on either to provide connectivity to the Internet. Chapter 3: ROUTING IP4 ROUTER FUNCTIONS Has a minimum of two network interfaces Holds a table of network information that it uses to make routing decisions Can be either a hardware device or a software application Has a minimum of two network interfaces Holds a table of network information that it uses to make routing decisions Can be either a hardware device or a software application Chapter 3: ROUTING IP5 ROUTING LAN TRAFFIC Chapter 3: ROUTING IP6 WAN ROUTING Chapter 3: ROUTING IP7 CHOOSING A WAN TOPOLOGY Mesh Ring Star Mesh Ring Star Chapter 3: ROUTING IP8 MESH TOPOLOGY Chapter 3: ROUTING IP9 RING TOPOLOGY Chapter 3: ROUTING IP10 STAR TOPOLOGY Chapter 3: ROUTING IP11 SELECTING A WAN TECHNOLOGY Leased Lines More expensive than dial on demand Guaranteed always-on service Dial on Demand Generally less expensive Pay for what you use Leased Lines More expensive than dial on demand Guaranteed always-on service Dial on Demand Generally less expensive Pay for what you use Chapter 3: ROUTING IP12 USING LEASED LINES Permanent, always-on connection Expensive to install and run Can only be used to connect to a specified location Normally provided as a managed service by a communications company Permanent, always-on connection Expensive to install and run Can only be used to connect to a specified location Normally provided as a managed service by a communications company Chapter 3: ROUTING IP13 USING DIAL-ON-DEMAND CONNECTIONS Includes ISDN, modem Links only used when necessary Normally charged on a usage basis Less expensive than leased-line installations Can be used to connect to more than one location Includes ISDN, modem Links only used when necessary Normally charged on a usage basis Less expensive than leased-line installations Can be used to connect to more than one location Chapter 3: ROUTING IP14 USING FRAME RELAY Chapter 3: ROUTING IP15 USING VIRTUAL PRIVATE NETWORKS Chapter 3: ROUTING IP16 ROUTING IP MULTICAST TRAFFIC Chapter 3: ROUTING IP17 USING NETWORK SWITCHES Chapter 3: ROUTING IP18 SWITCHES, ROUTERS, AND PERFORMANCE Switches are more expensive than hubs. Switches are less expensive than routers. Switches provide excellent performance improvements over hub-based networks. Switches are more expensive than hubs. Switches are less expensive than routers. Switches provide excellent performance improvements over hub-based networks. Chapter 3: ROUTING IP19 COMBINING ROUTING AND SWITCHING A switch reduces collisions but does not create a broadcast domain. Implementation of VLANs allows creation of broadcast domains. Ability to create a VLAN depends on the switch. A switch reduces collisions but does not create a broadcast domain. Implementation of VLANs allows creation of broadcast domains. Ability to create a VLAN depends on the switch. Chapter 3: ROUTING IP20 SELECTING ROUTERS AND SWITCHES Software based Places processing overhead on host server Allows functionality to be added or removed easily Hardware based Generally faster and more reliable than software based routers More difficult to add or remove features Software based Places processing overhead on host server Allows functionality to be added or removed easily Hardware based Generally faster and more reliable than software based routers More difficult to add or remove features Chapter 3: ROUTING IP21 UNDERSTANDING ROUTING TABLES The routing table contains a listing for each route including: Network Address NetMask Gateway Address Interface Metric The routing table contains a listing for each route including: Network Address NetMask Gateway Address Interface Metric Chapter 3: ROUTING IP22 STATIC VERSUS DYNAMIC ROUTING Static routing An administrator manually enters information into the routing table, using a program designed for that purpose. Dynamic routing The router receives routing table information automatically from other routers, using a specialized routing protocol. Static routing An administrator manually enters information into the routing table, using a program designed for that purpose. Dynamic routing The router receives routing table information automatically from other routers, using a specialized routing protocol. Chapter 3: ROUTING IP23 USING STATIC ROUTING Requires routes to be configured manually Route.exe command line utility Routing and Remote Access MMC snap-in Requires routes to be configured manually Route.exe command line utility Routing and Remote Access MMC snap-in Chapter 3: ROUTING IP24 USING DYNAMIC ROUTING Specialized routing protocols communicate information between routers. Self-maintaining. Requires no intervention in the event of a topology change. Specialized routing protocols communicate information between routers. Self-maintaining. Requires no intervention in the event of a topology change. Chapter 3: ROUTING IP25 SELECTING A ROUTING PROTOCOL Distance vector routing protocols Less administration Better suited to smaller networks Link state routing protocols Require more administration More effective in larger networks Distance vector routing protocols Less administration Better suited to smaller networks Link state routing protocols Require more administration More effective in larger networks Chapter 3: ROUTING IP26 DISTANCE VECTOR ROUTING Uses simple hop count to determine route to take across the network 1 router = 1 hop Doesnt necessarily indicate the best or fastest route Uses simple hop count to determine route to take across the network 1 router = 1 hop Doesnt necessarily indicate the best or fastest route Chapter 3: ROUTING IP27 LINK STATE ROUTING Uses complex algorithms to determine preferred route The number of hops between the router and the destination The transmission speed of the links connecting the router to the destination Delays caused by network traffic congestion A route cost value, supplied by an administrator Uses complex algorithms to determine preferred route The number of hops between the router and the destination The transmission speed of the links connecting the router to the destination Delays caused by network traffic congestion A route cost value, supplied by an administrator Chapter 3: ROUTING IP28 UNDERSTANDING ROUTING PROTOCOL COMMUNICATIONS Distance vector Each router transmits information about every router it knows about to every other router on the network. Information is retransmitted periodically irrespective of any change in the network topology. Link state After initial discovery, only changes are transmitted. Information is only transmitted to neighboring routers. Distance vector Each router transmits information about every router it knows about to every other router on the network. Information is retransmitted periodically irrespective of any change in the network topology. Link state After initial discovery, only changes are transmitted. Information is only transmitted to neighboring routers. Chapter 3: ROUTING IP29 ADMINISTERING ROUTING PROTOCOLS Distance vector Minimal configuration Minimal ongoing administration Link state Potentially complex configuration Minimal ongoing administration Distance vector Minimal configuration Minimal ongoing administration Link state Potentially complex configuration Minimal ongoing administration Chapter 3: ROUTING IP30 USING ROUTING AND REMOTE ACCESS RRAS Service in Windows 2003 Configured via the Routing and Remote Access MMC snap-in RRAS Service in Windows 2003 Configured via the Routing and Remote Access MMC snap-in Chapter 3: ROUTING IP31 CHAPTER SUMMARY Routers enable communication between networks. Routers can take the form of software or hardware. A WAN topology defines the pattern of connections among your network sites. Multicasting allows you to send data to a group of machines using a single IP address. Routers enable communication between networks. Routers can take the form of software or hardware. A WAN topology defines the pattern of connections among your network sites. Multicasting allows you to send data to a group of machines using a single IP address. Chapter 3: ROUTING IP32 CHAPTER SUMMARY (continued) Static routing describes the manual creation of routing table entries. Dynamic routing uses specialized routing protocols to update changes in the network topology. RRAS can be used on Windows Server 2003 systems to configure static and dynamic routing. Static routing describes the manual creation of routing table entries. Dynamic routing uses specialized routing protocols to update changes in the network topology. RRAS can be used on Windows Server 2003 systems to configure static and dynamic routing.