chap 3

• Dynamic routing protocols have been used in networks since the late 1980s
• RIPv1 was released in 1988, with basic algorithms used on ARPANET as early as 1969
• RIPv2 was developed to accommodate network growth, but it does not scale well to larger network implementations
• Advanced routing protocols for larger networks include OSPF, IS-IS, IGRP, and EIGRP
• BGP is used between ISPs and larger private clients for routing information exchange
• Dynamic routing protocols facilitate the exchange of routing information between routers
• Purpose of dynamic routing protocols:

  • Discovery of remote networks
  • Maintaining up-to-date routing information
  • Choosing the best path to destination networks
  • Ability to find a new best path if the current path is no longer available
• Main components of dynamic routing protocols:

  • Data structures: tables or databases used for operations
  • Routing protocol messages: used for discovering neighboring routers, exchanging routing information, and learning about the network
  • Algorithm: finite list of steps used for routing information and best path determination
• Static routing is used in smaller networks that are not expected to grow significantly
• Primary uses of static routing:

  • Ease of routing table maintenance in smaller networks
  • Routing to and from a stub network
  • Accessing a single default route
• Advantages of static routing:

  • Easy to implement in small networks
  • Routes stay the same, making them easy to troubleshoot
  • Requires very little overhead
• Disadvantages of static routing:

  • Not easy to implement in large networks
  • Managing static configurations can be time-consuming
  • Cannot reroute traffic if a link fails
• Dynamic routing protocols help manage the configuration and maintenance of static routes
• Advantages of dynamic routing:

  • Works well in networks with several routers
  • Automatically determines better routes with topology changes
  • Simpler to configure than static routing in large networks
• Disadvantages of dynamic routing:

  • Requires knowledge of additional commands
  • Less secure than static routing
  • Uses additional CPU, RAM, and link bandwidth
• RIP is rarely used in modern networks but is useful for understanding basic network routing
• To enable RIP, use the 'router rip' command in router configuration mode
• To advertise networks in RIP, use the 'network network-address' command in router configuration mode
• Use the 'show ip protocols' command to display IPv4 routing protocol settings on the router
• To enable RIPv2, use the 'version 2' command in router configuration mode
• Use the 'passive-interface' command to prevent the transmission of routing updates through a router interface
• To propagate a default route in RIP, configure a default static route and use the 'default-information originate' command
• Routing table entries for directly connected networks include route source, destination network, and outgoing interface
• Route source codes in routing tables:

  • C: directly connected network
  • L: local route
  • S: manually created static route
  • D: learned dynamically from another router using EIGRP
  • O: learned dynamically from another router using OSPF
  • R: learned dynamically from another router using RIP