Chapter 3 Dynamic Routing (Dynamic Routing Protocol Components: A routing…
Chapter 3 Dynamic Routing
Dynamic Routing Protocol Evolution:One of the first routing protocols was RIP.
Dynamic Routing Protocol Components: A routing protocol is a set of processes, algorithms, and messages that are used to exchange routing information and populate the routing table with the routing protocol's choice of best paths.The purpose of dynamic routing protocols includes;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
The main components of dynamic routing protocols include: Data structures - Routing protocols typically use tables or databases for its operations. Routing protocol messages - Routing protocols use various types of messages to discover neighboring routers, exchange routing information, and other tasks to learn and maintain accurate information about the network. Algorithm - An algorithm is a finite list of steps used to accomplish a task
Static Routing Uses: Static routing has several primary uses, including; Providing ease of routing table maintenance in smaller networks, Routing to and from a stub network, Accessing a single default route
Static Routing Advantages and Disadvantages: easy to implement in a small network, stay the same, do not send update message, not easy to implement in a large network, configurations can become time consuming, If a link fails, a static route cannot reroute traffic
Dynamic Routing Protocols Uses: Dynamic routing protocols can help the network administrator manage the time-consuming and exacting process of config. and maintain static routes.
Dynamic Routing Advantages and Disadvantages: suitable in all topologies, independent, automatically adapts topology to reroute traffic, complex to implement, less secure, depends on current topology, requires additional CPU, RAM, and bandwidth
Router RIP Configuration Mode: router rip command provides access to the router configuration mode where the RIP routing settings are configured. No router rip stops the RIP process and erases all existing RIP configurations
Advertise Networks: To enable RIP routing for a network, use the network network-address router configuration mode command. This command Enables RIP on all interfaces that belong to a specific network.Advertises the specified network in RIP routing updates
Verify RIP Routing: show ip protocols command displays the IPv4 routing protocol settings currently configured on the route
Enable and Verify RIPv2: when a RIP process is configured on a Cisco router, it is running RIPv1. Use the version 2 router configuration mode command to enable RIPv2. show ip protocols command verifies that R2 is now configured to send and receive version 2 messages only
Disable Auto Summarization: RIPv2 automatically summarizes networks at major network boundaries by default. To modify the default RIPv2 behavior of automatic summarization, use the no auto-summary
Configure Passive Interfaces: Sending out unneeded updates on a LAN impacts the network in three ways. Wasted Bandwidth - Bandwidth is used to transport unnecessary updates. Wasted Resources - All devices on the LAN must process the update up to the transport layers. Security Risk - Advertising updates on a broadcast network is a security risk. passive-interface router configuration command to prevent the transmission of routing updates through a router interface
Propagate a Default Route: To propagate a default route in RIP, the edge router must be configured with, A default static route using the ip route 0.0.0.0 0.0.0.0 command, The default-information originate router configuration command.
Routing Table Entries: R1 is the edge router that connects to the Internet, R1, R2, and R3 contain dis-contiguous networks separated by another classful network, R3 is also introducing a 192.168.0.0/16 supernet route
Directly Connected Entries: Route source - Identifies how the route was learned. Destination network - The address of the remote network and how that network is connected. Outgoing interface - Identifies the exit interface to use when forwarding packets to the destination network.
Remote Network Entries: Route source - Identifies how the route was learned. Destination network - Identifies the address of the remote network. Administrative distance (AD) - Identifies the trustworthiness of the route source. Metric - Identifies the value assigned to reach the remote network. Next hop - Identifies the IPv4 address of the next router to forward the packet to. Route timestamp - Identifies from when the route was last heard. Outgoing interface - Identifies the exit interface to use to forward a packet toward the final destination.
Routing Table Terms: A dynamically built routing table provides a great deal of information. Special terms are applied when discussing the contents of a routing table
Ultimate Route: An ultimate route is a routing table entry that contains either a next-hop IPv4 address or an exit interface.
Level 1 Route: A level 1 route is a route with a subnet mask equal to or less than the classful mask of the network address.Could be a, Network route - A network route that has a subnet mask equal to that of the classful mask, Supernet route - A supernet route is a network address with a mask less than the classful mask, Default route - A default route is a static route with the address 0.0.0.0/0
Level 1 Parent Route: A parent route is a level 1 network route that is subnetted. A parent route can never be an ultimate route.
Level 2 Child Route: A level 2 child route is a route that is a subnet of a classful network address. Like a level 1 route, the source of a level 2 route can be a directly connected network, a static route, or a dynamically learned route.
Directly Connected Entries: directly connected route entries display the following information- Route source, Directly connected network, Administrative distance, Metric, and Outgoing interface
Remote IPv6 Network Entries: The entry identifies the following information- Route source, Destination network, Administrative distance, Metric, Next hop, Outgoing interface.