Lecturer : Ms.Trần Thị Ngọc Hoa Chapter 5 IP Routing

Lecturer : Ms.Trần Thị Ngọc Hoa Objectives  Switching Revision  Routing Process  Static Routing  Default Route  Interior Routing Protocol  Lab Demo

Lecturer : Ms.Trần Thị Ngọc Hoa AAAA DDDD BBBB CCCC E0E3 E2E1 Layer 2 Switching Operation  Address learning  Forward/filter decision MAC Address Table E AAAA

Lecturer : Ms.Trần Thị Ngọc Hoa Layer 2 Switching Operation (cont) AAAA DDDD BBBB CCCC MAC Address Table E AAAA E DDDD E0 E3 E2 E1

Lecturer : Ms.Trần Thị Ngọc Hoa AAAA DDDD BBBB CCCC MAC Address Table E AAAA E DDDD E CCCC E0 E3 E2E1 Layer 2 Switching Operation (cont)

Lecturer : Ms.Trần Thị Ngọc Hoa Layer 2 Switching Operation (cont) AAAA DDDD BBBB CCCC MAC Address Table E AAAA E DDDD E CCCC E BBBB E0E3 E2 E1 Broadcast storm

Lecturer : Ms.Trần Thị Ngọc Hoa Routing Process Overview Receiving frame Check the Destination MAC address Detemine the Destination MAC address of next hop Encapsulate the frame & forward to the next hop Discard the frame’s header and trailer Error ? Discard the frame Router’s MAC ? Find the route Report the error or send to the default route Y Discard the frame Y N N N Y

Lecturer : Ms.Trần Thị Ngọc Hoa FA0/0 FA0/1 IP Routing Process Example / / / R_1 R_2

Lecturer : Ms.Trần Thị Ngọc Hoa R1 R2 R3 s0 s1 Static Routing / / / / / /24  There are three methods by which Routers use to add routes to their routing table. Connected routes Static routes Dynamic routes  Router(config)#ip route network [mask] {next-hop address | outgoing interface} [distance] [permanent] R1(config)# ip route s0 R1(config)# ip route

Lecturer : Ms.Trần Thị Ngọc Hoa Static Routing (cont)  Advantages 1. No overhead on Router’s processor 2. No bandwidth for transfering routing traffics between Routers 3. More security

Lecturer : Ms.Trần Thị Ngọc Hoa Static Routing (cont)  Disadvantages For administrator :  Must understand clearly the internetwork  Must master the cabling diagram among routers  No flexibility  No feasibility in large or medium internetworks

Lecturer : Ms.Trần Thị Ngọc Hoa Static Routing (cont)  Default Route  Special route that matches all packet destinations.

Lecturer : Ms.Trần Thị Ngọc Hoa Static Routing (cont)  Commands : ip route nexthop ip default-network classful_network / / / /

Lecturer : Ms.Trần Thị Ngọc Hoa

Static Routes (cont)  Classless Routing and Classful Routing : two options for how a router uses a default route  Classless Routing : a router uses default routes for any packet that does not match the other routes.  Classful Routing : places one restriction when a router can use its default route  Remember these commands : ip classless and no ip classless

Lecturer : Ms.Trần Thị Ngọc Hoa

Dynamic Routing  General Routing Protocol Function 1. Router learn routing information from other neighboring routers 2. Advertise its routing information to the other neighboring routers 3. If more than one route exists to reach one network, pick the best one based on a metric 4. Support convergence if the network topology changes

Lecturer : Ms.Trần Thị Ngọc Hoa Dynamic Routing  Two catgories of routing protocols IGP – Interior Gateway Protocol EGP – Exterior Gateway Protocol  IGP : used for inside a single Autonomous System – AS.  EGP: used for between different AS.  AS : internetwork under the administrative control of a single organization.  ASN : managed by ICANN - Internet Corporation for Assigned Network Number

Lecturer : Ms.Trần Thị Ngọc Hoa Interior Routing Protocols  Three branches : Distance Vector :  RIP – Routing Information Protocol  IGRP – Interior Gateway Routing Protocol Link-State :  OSPF – Open Shortest Path Fist  IS-IS – Intermediate System to Intermediate System Balanced hybrid  EIGRP – Enhanced IGRP

Lecturer : Ms.Trần Thị Ngọc Hoa Administrative Distance Route TypeAD Connected0 Static1 BGP(external routes)20 EIGRP (internal routes)90 IGRP100 OSPF110 IS-IS115 RIP120 EIGRP (external routes)170 BGP(internal routes)200

Lecturer : Ms.Trần Thị Ngọc Hoa Distance Vector Routing Protocol  Operation in a stable network  Loop Prevention S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2

Lecturer : Ms.Trần Thị Ngọc Hoa Operation in A Stable Network Source Subnet Out.Int Nexthop Metric Conn /24S0/0 N/A 0 Conn /24 Fa0/0 N/A 0 RIP /24S0/ RIP /24S0/ Source Subnet Out.Int Nexthop Metric Conn /24Fa0/0 N/A 0 Conn /24 Fa0/1 N/A 0 Conn /24S0/1N/A0 RIP /24S0/ , metric 1 RIP Update , metric , metric 1 RIP Update , metric 1 RIP Update , metric , metric 1 RIP Update S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2

Lecturer : Ms.Trần Thị Ngọc Hoa S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2 Routing Problem Source Subnet Out.Int Nexthop Metric Conn /24S0/0 N/A 0 Conn /24 Fa0/0 N/A 0 RIP /24S0/ RIP /24S0/ Source Subnet Out.Int Nexthop Metric Conn /24Fa0/0 N/A 0 Conn /24 Fa0/1 N/A 0 Conn /24S0/1N/A0 RIP /24S0/

Lecturer : Ms.Trần Thị Ngọc Hoa Loop Prevention  Route Poisoning  Split Horizon with Triggered Updates  Holddown process

Lecturer : Ms.Trần Thị Ngọc Hoa S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2 Route Poisoning Source Subnet Out.Int Nexthop Metric Conn /24S0/0 N/A 0 Conn /24 Fa0/0 N/A 0 RIP /24S0/ RIP /24S0/ Source Subnet Out.Int Nexthop Metric Conn /24Fa0/0 N/A 0 Conn /24 Fa0/1 N/A 0 Conn /24S0/1N/A0 RIP /24S0/ , metric , metric 16 RIP Update

Lecturer : Ms.Trần Thị Ngọc Hoa S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2 Split Horizon- Triggered Update Source Subnet Out.Int Nexthop Metric Conn /24S0/0 N/A 0 Conn /24 Fa0/0 N/A 0 RIP /24S0/ RIP /24S0/ Source Subnet Out.Int Nexthop Metric Conn /24Fa0/0 N/A 0 Conn /24 Fa0/1 N/A 0 Conn /24S0/1N/A0 RIP /24S0/ , metric , metric 16 RIP Update , metric , metric , metric 2 RIP Update

Lecturer : Ms.Trần Thị Ngọc Hoa S0/ S0/ Fa0/ /24 Fa0/ / /24 Fa0/1 R_1 R_2 Holddown Process R_4 R_3

Lecturer : Ms.Trần Thị Ngọc Hoa Timers TimerRIPIGRP Route Update30s90s Route Invalid180s270s Holddown180s280s Route Flush240s630s

Lecturer : Ms.Trần Thị Ngọc Hoa Lab Demo HaNoi HCM HN_1 HCM_1 HCM_2 HN_2 Internet XYZ Network RIP / / / / /24