Router Trustworthiness Quiz & Flashcards

Study Notes

IP Routing

IP routing is the process of moving packets from one network to another network using routers.
Routing protocols are used by routers to dynamically find all networks.
Examples of routing protocols include RIP, RIPv2, EIGRP, and OSPF.

Routing Basics

A router must know the following minimum factors to effectively route packets:
- Destination address
- Neighbor routers from which it can learn about remote networks
- Possible routes to all remote networks
- The best route to each remote network
- How to maintain and verify routing information
The router learns about remote networks from neighboring routers or from an administrator.
The router builds a routing table, which is a map of the internetwork, describing how to find remote networks.

Simple Routing Example

A simple network example shows a router (Lab_A) with four interfaces.
The router uses the interface with the best route to forward an IP datagram to a host with a destination IP address of 10.10.10.30.

IP Routing Process

The IP routing process involves:
- Host_A sending an IP datagram to Host_B on a different network.
- The router performing a lookup to find the best route to the destination network.
- The router forwarding the IP datagram to the next hop on the best route.

Packet-Forwarding Techniques

Cisco uses three types of packet-forwarding techniques:
- Process Switching: looks up every destination in the routing table and finds the exit interface for every packet.
- Fast Switching: uses a cache to store the most recently used destinations.
- Cisco Express Forwarding (CEF): uses multiple cache tables to improve performance and adapt to network topology changes.

Types of Routing

Static Routing:
- Routes are manually configured by the administrator.
- Requires destination network ID for configuration.
- Used in small networks.
- Administrator distance for static route is 1.
Dynamic Routing:
- Uses dynamic routing protocols to find networks and update routing tables.
- Requires directly connected network IDs for configuration.
- Used in medium and large networks.
- Administrator work is reduced.

Static Routing Pros and Cons

Pros:
- No overhead on the router CPU.
- No bandwidth usage between routers.
- Adds security by allowing exclusive routing access to certain networks.
Cons:
- Requires administrator to have a thorough knowledge of the internetwork.
- Tedious to add routes to new networks on all routers.
- Not feasible for large networks due to high maintenance requirements.

Dynamic Routing Protocols

Types of dynamic routing protocols:
- Distance Vector Protocol: RIP (Routing Information Protocol).
- Link State Protocol: OSPF (Open Shortest Path First).
- Hybrid Protocol: EIGRP (Enhanced Interior Gateway Routing Protocol).

Administrative Distances

Administrative Distance (AD) is used to rate the trustworthiness of routing information received on a router from a neighbor router.
AD is an integer from 0 to 255, where 0 is the most trusted and 255 means no traffic is passed via this route.
If a router receives two updates listing the same remote network, the route with the lowest AD will be chosen and placed in the routing table.

Description

Test your knowledge of IP routing, routing protocols and routed protocols in computer networks. Learn about RIP, RIPv2, EIGRP, OSPF and more. Assess your understanding of routing basics and its applications.