Static Routing TechniqueStatic Routing Technique

What is RoutingWhat is Routing

the act of moving information across an internetwork from a source to a destination

Bridge

the mid-1980s

Routing ComponentsRouting Components

Path DeterminationPath Determination

SwitchingSwitching

Routing AlgorithmsRouting Algorithms Design GoalDesign Goal

OptimalityOptimality Simplicity and low overheadSimplicity and low overhead Robustness and stabilityRobustness and stability Rapid convergenceRapid convergence FlexibilityFlexibility

Routing AlgorithmsRouting Algorithms Algorithm TypesAlgorithm Types

Static Versus DynamicStatic Versus Dynamic Single-Path Versus MultipathSingle-Path Versus Multipath Flat Versus HierarchicalFlat Versus Hierarchical Host-Intelligent Versus Router-IntelligentHost-Intelligent Versus Router-Intelligent Intradomain Versus InterdomainIntradomain Versus Interdomain Link-State Versus Distance VectorLink-State Versus Distance Vector Routing MetricsRouting Metrics

Routing MetricsRouting MetricsPath lengthReliabilityDelayBandwidthLoadCommunication cost

Static RoutingStatic Routing

manually configure routers by administrator

Entrys in the routing table may be a destination.

paths are unchangeable.

DynamicDynamic RoutingRouting

routing algorithms

discover changes, automatically adjust routing tables, and inform other routers.

some paths may be manually configured to control the routing environment.

Static vs Dynamic Static vs Dynamic FunctionFunction StaticStatic DynamicDynamic

Routing TablesRouting Tables Manually created and mManually created and maintainedaintained Dynamically builtDynamically built

Sharing InformationSharing Information Does not share informatiDoes not share informationon

Share information amonShare information among routersg routers

Route DiscoveryRoute Discovery Function of IPFunction of IP Function of Routing protFunction of Routing protocol(e.g.,RIP)ocol(e.g.,RIP)

Internetwork Internetwork SmallSmall LargeLarge

Ps. Most routers support both static and dynamic routing.

Static Static RoutingRouting in Linux and IO in Linux and IOSS

Most dynamic routingMost dynamic routing static routing to configure their default route static routing to configure their default route routers run a routing protocol that automatically updarouters run a routing protocol that automatically upda

tes routing tables tes routing tables Static routing entries can be added, even if a router ruStatic routing entries can be added, even if a router ru

ns a routing protocol, however, static routes may interns a routing protocol, however, static routes may interfere with the path calculation determined by a routing fere with the path calculation determined by a routing protocol.protocol.

configuration file configuration file

Static Routing in Linux and IOS(2)Static Routing in Linux and IOS(2)

routing cache. routing cache.

a separate entry for each destination IP address.a separate entry for each destination IP address.

delete if it has not been used for some time.delete if it has not been used for some time.

Routing ProtocolRouting Protocol

Routing Information Protocol (RIP) Routing Information Protocol (RIP)

HelloHello

Open Shortest Path First (OSPF)Open Shortest Path First (OSPF)

Debugging static routing configuratiDebugging static routing configurationsons

Tools and UtilitiesTools and UtilitiesEtherealEtherealPingPingTracerouteTraceroutenetstat –rnnetstat –rnShow ip routeShow ip route

Debugging static routing configuratiDebugging static routing configurations(2)ons(2)

ExampleExampleping: find unsuccessful connectionsping: find unsuccessful connections traceroute: find the last successful routertraceroute: find the last successful routernetstat –rn / show ip route: determine which routinnetstat –rn / show ip route: determine which routin

g table entry is incorrect or missing.g table entry is incorrect or missing.