INTRODUCTION TO COMPUTER NETWORK

PHYSICAL LAYER

DATA LINK LAYER

NETWORK LAYER

TRANSPORT LAYER

MCQ- COMPUTER NETWORK

APPLICATION LAYER

NETWORK SECURITY

MULTIMEDIA AND FUTURE NETWORKING

COMPUTER NETWORK LAB WORK

Routing and Routing Table

Routing is a fundamental concept in computer networking that involves determining the optimal path for data to travel from the source to the destination in a network. It plays a crucial role in directing data packets through various interconnected devices, such as routers and switches, to ensure efficient and reliable communication.

In a network, routers are the devices responsible for making routing decisions. These decisions are based on routing tables, which contain information about the network topology, available paths, and the associated costs. The goal of routing is to find the most efficient route for data transmission, considering factors like speed, reliability, and cost.

The routing process typically involves the following steps:

  • Packet Forwarding: Routers examine the destination address of incoming data packets and use the routing table to determine the next hop or interface for forwarding the packets.
  • Routing Table Updates: Dynamic routing protocols constantly exchange information between routers to update their routing tables. This ensures that routers have the latest information about network changes.
  • Path Selection: Routers evaluate various factors, such as link cost, available bandwidth, and network congestion, to select the most efficient path for data transmission.
  • Error Handling: Routers are equipped to handle errors or failures in the network. If a link or router becomes unavailable, the routing protocol should quickly adapt and reroute traffic to maintain connectivity.

Routing Table 

 

A routing table is a data table stored in a router or a networked computer, containing information about the available routes to various network destinations. Each entry in the routing table consists of a destination network address, the next hop (the next device to which the data should be sent), and additional metrics or attributes that help the router make decisions about the best path to reach a specific destination.

Here are the key components found in a typical routing table entry:

  • Destination Network: This is the IP address or network address of the destination to which the router wants to send data. It represents the target network or host.
  • Subnet Mask: The subnet mask defines the range of IP addresses included in the destination network. It helps the router identify which portion of the IP address is the network address and which is the host address.
  • Next Hop: This is the IP address of the next device or router on the path to reach the destination network. The router uses this information to determine where to forward the data packet.
  • Interface: Instead of specifying the next hop directly, some routing tables may list the outgoing interface (e.g., Ethernet interface, Serial interface) through which the router should send the packet to reach the next hop.
  • Metric/Cost: This is a value associated with the route that represents the cost or preference of using that particular route. It helps the router choose the most optimal path among multiple available paths.