IP Routing

IP Routing

1. Overview

   • IP Addressing
     • IPv4
       • 192.168.45.99
     • IPv6
       • C01A:CA22:1::1/64
   • Networks
     • source and destination have different network addresses
   • Network Addresses and Subnet Masks
     • A subnet mask defines which bits identify the network and which identify the individual host.
   • Classful Networks
     • Class A networks have 8-bit network addresses.
       • The 126 class A networks range from 1.0.0.0 to 126.0.0.0
     • Class B network addresses
       • The 16,384 class B networks range from 128.0.0.0 to 191.255.0.0
     • Class C networks have 24-bit network addresses
       • The 2,097,252 class C networks range from 192.0.0.0 to 223.255.255.0
     • Class D networks have 32-bit network addresses
       • These networks are used for multicasting and range from 224.0.0.0 to 239.255.255.255.
   • CIDR
     • Many organizations need more addresses than a Class C network provides, but fewer than a Class B network does.
   • Routing Table
     • ■destination network address ■subnet mask ■next-hop address ■forwarding interface ■metric ■administrative distance
     • Destination Network Ad dress and Subnet Mask
       • The subnet mask defines how many bits the router examines when matching the two addresses.
     • Next-Hop Address and Forwarding Interface
       • Is the address of the next directly-connected device en route to the destination address
     • Administrative Distance and Metric
       • A route’s administrative distance indicates how reliable the router considers the method through which it discovered the route
   • Static Routing
     • Static routes are routes that you manually add to the routing table
   • Dynamic Routing Protocols
     • RIP versions 1 and 2
     • Open Shortest Path First (OSPF) version 2
     • Border Gateway Protocol (BGP) version 4
   • Static Routing Versus Dynamic Routing
     • Static routing is secure because it provides you the tightest control over traffic flow:
     • Dynamic routing can provide reliable routes.
   • Load Sharing
     • When you enable load sharing, the router can place up to six routes to the same destination in its active routing table.
   • Fast Caching
     • Is designed to speed processing of packets that follow often-used routes