Chapter 5 – TCP/IP: Routing – Part 2TCP/IP – Routing - Part 4bRouting Protocols Autonomous System of NetworksRouting ProtocolsSlide 5Slide 6Comparison of Routing ProtocolsTCP/IP and RoutingRouting Tables Routing Table for BRouting Table (Continued)Introduction Router Forwarding TableUnicast/BroadcastChapter 5 – TCP/IP: Routing – Part 2Dr. V.T. RajaOregon State UniversityTCP/IP – Routing - Part 4bOutlineRouting ProtocolsRouting TablesUnicast messagesBroadcast messagesRouting ProtocolsAutonomous System of NetworksAutonomous System of NetworksEach large organizational network connected to Internet (e.g., AT&T, IBM, OSU) can be viewed as a separate autonomous systemComputers within each autonomous system usually exchange routing information among themselvesRouting protocols used inside an autonomous system are called interior routing protocolsRouting protocols used between autonomous systems are called exterior routing protocolsRouting ProtocolsInternet Control Message Protocol (ICMP)–Error advisement •Example: Ping command – Host (Destination) unreachable–Flow control•Requesting a device to reduce the rate at which it transmitsRouting ProtocolsRouting Information Protocol (RIP)–Dynamic distance vector routing protocol–Scalability: 15-hop limit–Good for smaller networks–Broadcast interruptions (entire routing table transmitted very often)–Slower convergence – Takes a longer time for routing tables to be transmitted very oftenRouting ProtocolsOpen Shortest Path First (OSPF) –Link State Dynamic Routing Protocol–Faster convergence •Designated router updated on changes in route statusBorder Gateway Protocol (BGP)–Distance Vector Dynamic Routing Protocol–Used between autonomous systems–Changes in route status info transmittedComparison of Routing ProtocolsRIP OSPF BGPInterior/Exterior? Interior Interior ExteriorType (Distance Vector/ Link State?)Distance Vector Link State Distance VectorRouting update content(Routing Table/Updates?)Routing Table Updates only Updates onlyRouting update frequencyVery often (e.g., every 30 seconds)Updates only Updates onlyConvergence(Slow/Fast/Complex?)Slow Fast ComplexScalability Poor Very Good Very GoodTCP/IP and RoutingTCP/IP can use RIP, ICMP, OSPF, BGPIt is compatible with distance vector and link state protocolsCan operate either as connectionless or connection oriented routing Can support QoS routing (a new version of OSPF called QOSPF)Routing TablesRouting Table for BDestination RouteA AC CD AE EF EG CDefault ARouting Table (Continued)NetworkDestinationNetmask Gateway Interface Metric(Cost)Default route: 0.0.0.0 0.0.0.0 128.193.76.1 128.193.77.65 20Loop back (Self)127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1Network Route128.193.76.0 255.255.254.0 128.193.77.65 128.193.77.65 20Local Host128.193.77.65 255.255.255.255 127.0.0.1 127.0.0.1 20Subnet broadcast128.193.255.255 255.255.255.255 128.193.77.65 128.193.77.65 20Multicast: 224.0.0.0 240.0.0.0 128.193.77.65 128.193.77.65 20Broadcast255.255.255.255255.255.255.255 128.193.77.65 128.193.77.65 1IntroductionRouter Forwarding TableDestination Address Prefix (Mask) Metric (Cost) Interface Next-Hop Router172.19. 16 (255.255.0.0) 47 2 G172.19.17 24 55 3 H172.229. 16 34 1 F172.229. 16 20 3 H172.15.122 24 3 3 Local0.0.0.0 0 5 3 HUnicast/BroadcastUnicast/BroadcastUnicast–Most common type of message transmitted (from one sender to one final destination)–Example:Broadcast–Subnet broadcast•Example–LAN
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