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Instructor & Todd Lammle. Sybex CCNA 640-802 Chapter 8: IP Routing. Chapter 8 Objectives. Understanding IP routing Static routing Dynamic routing RIP RIPv2 OSPF EIGRP Verifying routing Router Security. 2. To route a router need to know: Remote Networks Neighbor Routers
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Instructor & Todd Lammle Sybex CCNA 640-802 Chapter 8: IP Routing
Chapter 8 Objectives • Understanding IP routing • Static routing • Dynamic routing • RIP • RIPv2 • OSPF • EIGRP • Verifying routing • Router Security 2
To route a router need to know: Remote Networks Neighbor Routers All Possible routes to remote network The absolute best route to all remote networks Maintain and verify the routing information What is Routing? A D C B
To route a router need to know: Remote Networks Neighbor Routers All Possible routes to remote network The absolute best route to all remote networks Maintain and verify the routing information What is Routing? A D C B
Basic Path Selection What interface will the router send out a packet if it has destination address of 10.10.10.10?
Simple IP Routing >ping 172.16.20.2
Routing/PDU Example: Host A Web browses to the HTTP Server…. 1. The destination address of a frame will be the _______________________ 2. The destination IP address of a packet will be the IP address of the________________________________ 3. The destination port number in a segment header will have a value of __
Static Routes Stub Network 172.16.1.0 172.16.2.0 SO SO A A B B 172.16.3.1 172.16.3.2 Routes must be unidirectional
Static Route Configuration ip route remotenetwork [mask] {address|interface} [distance] [permanent] Router(config)#ip route remote_network mask next_hop
Static Route Example Stub Network 172.16.2.0 172.16.1.0 SO SO A B B 172.16.3.1 172.16.3.2 ip route 172.16.1.0 255.255.255.0 172.16.3.2or ip route 172.16.1.0 255.255.255.0 s0
Default Routes Stub Network 172.16.1.0 172.16.2.0 SO SO A B B 172.16.3.1 172.16.3.2 ip route 0.0.0.0 0.0.0.0 172.16.3.1 ip classless
Routing vs. Routed • Routing protocols are used between routers to: • Determine the path of a packet through a network • Maintain routing tables • Examples? • Routed protocols are: • Assigned to an interface • Once the path is determined by the Routing protocol, determines method of delivery • Examples?
Routing Protocols IGPs: RIP, IGRP EGPs: BGP Autonomous System 1 Autonomous System 2 • An autonomous system is a collection of networks under a common administrative domain. • IGPs operate within an autonomous system. • EGPs connect different autonomous systems.
Classful Routing Overview Classful routing protocols do not include the subnet mask with the route advertisement. • Within the same network, consistency of the subnet masks is assumed. • Summary routes are exchanged between foreign networks. • Examples of classful routing protocols: • RIP Version 1 (RIPv1) • IGRP
Classless Routing Overview Classless routing protocols include the subnet mask with the route advertisement. • Classless routing protocols support variable-length subnet masking (VLSM). • Summary routes can be manually controlled within the network. • Examples of classless routing protocols: • RIP Version 2 (RIPv2) • EIGRP • OSPF • IS-IS
Administrative Distance Router B Router A IGRPAdministrative Distance=100 RIPAdministrative Distance=120 Router C Router D • Default Administrative Distance • Directly Connected: 0 • Static Route: 1 • RIP: 120 • IGRP: 100 • EIGRP: 90 • OSPF: 110
Distance Vector Distance—How farVector—In which direction A D C B Routing Table Routing Table Routing Table Routing Table Distance vector algorithms do not allow a router to know the exact topology of an internetwork. All routers just broadcast their entire routing table out all active interfaces on periodic time intervals
Router LoopPrevention • Maximum Hop Count • Split Horizon • Route Poisoning • Holddowns
RIP Overview 64kbps T1 T1 T1 • Hop count metric selects the path, 16 is unreachable • Full route table broadcast every 30 seconds • Load balance maximum of 6 equal cost paths (default = 4) • RIPv2 supports VLSM and Discontiguous networks
router RIP router RIP network 172.16.0.0 network 192.168.10.0 network 172.16.0.0 network 10.0.0.0 RIP Routing Configuration Router(config)#router rip Router(config-router)#network network-number* 192.168.10.0 10.3.5.0 172.16.10.0 *Network is a classful network address. Every device on network uses the same subnet mask
RIP Version 2 • Allows the use of variable length subnet masks (VLSM) by sending subnet mask information with each route update • Distance Vector – same AD, and timers. • Easy configuration, just add the command “version 2” under the router rip configuration router rip network 10.0.0.0 version 2
Discontiguous Addressing • Two networks of the same classful networks are separated by a different network address 192.168.10.0/24 192.168.10.0/24 10.1.1.0/24 • RIPv1 and IGRP do not advertise subnet masks, and therefore cannot support discontiguous subnets. • OSPF, EIGRP, and RIPv2 can advertise subnet masks, and therefore can support discontiguous subnets.
Passive Interface Maybe you don’t want to send RIP updates out your router interface connected to the Internet. Use the passive-interface command: Router(config)#router rip Router(config-router)#passive-interface serial0 X Updates Internet S0 Gateway This allows a router to receive route updates on an interface, but not send updates via that interface
Verifying RIP Router#show ip protocols Router#show ip route Router#debug ip rip Router#undebug all (un all)
Summary • Open your books and go through all the written labs and the review questions. • Review the answers in class. 28