Static Routing Technique What is Routing z the

Static Routing Technique

What is Routing z the act of moving information across an internetwork from a source to a destination z Bridge z the mid-1980 s

Routing Components z Path Determination z Switching

Routing Algorithms z Design Goal z Optimality z Simplicity and low overhead z Robustness and stability z Rapid convergence z Flexibility

Routing Algorithms z Algorithm Types z Static Versus Dynamic z Single-Path Versus Multipath z Flat Versus Hierarchical z Host-Intelligent Versus Router-Intelligent z Intradomain Versus Interdomain z Link-State Versus Distance Vector z Routing Metrics

Routing Metrics z Path length z Reliability z Delay z Bandwidth z Load z Communication cost

Static Routing z manually configure routers by administrator z Entrys in the routing table may be a destination. z paths are unchangeable.

Dynamic Routing z routing algorithms z discover changes, automatically adjust routing tables, and inform other routers. z some paths may be manually configured to control the routing environment.

Static vs Dynamic Function Static Dynamic Routing Tables Manually created and maintained Dynamically built Sharing Information Does not share information Share information among routers Route Discovery Function of IP Function of Routing protocol(e. g. , RIP) Internetwork Small Large Ps. Most routers support both static and dynamic routing.

Static Routing in Linux and IOS Most dynamic routing z static routing to configure their default route z routers run a routing protocol that automatically updates routing tables z Static routing entries can be added, even if a router runs a routing protocol, however, static routes may interfere with the path calculation determined by a routing protocol. z configuration file z

Static Routing in Linux and IOS(2) z routing cache. z a separate entry for each destination IP address. z delete if it has not been used for some time.

Routing Protocol z Routing Information Protocol (RIP) z Hello z Open Shortest Path First (OSPF)

Debugging static routing configurations z Tools and Utilities z Ethereal z Ping z Traceroute z netstat –rn z Show ip route

Debugging static routing configurations(2) z Example z ping: find unsuccessful connections z traceroute: find the last successful router z netstat –rn / show ip route: determine which routing table entry is incorrect or missing.