Computer Science – 2.1 Networks including the internet | e-Consult
2.1 Networks including the internet (1 questions)
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A router is a fundamental device in computer networks, responsible for forwarding data packets between different networks. Its primary role is to connect networks together, enabling communication between devices residing on those networks. It operates at the network layer (Layer 3) of the TCP/IP model, using IP addresses to determine the best path for data transmission.
Functionality:
- Packet Forwarding: The core function of a router is to examine the destination IP address in a packet's header and determine the next hop towards that destination.
- Routing Tables: Routers maintain routing tables, which are essentially maps of networks and the best paths to reach them. These tables are built using routing protocols.
- Network Address Translation (NAT): Many routers perform NAT, allowing multiple devices on a private network to share a single public IP address. This enhances security and conserves public IP addresses.
- Network Address (LAN) Support: Routers connect local area networks (LANs) to wider networks, such as the internet.
- Security Features: Modern routers often include firewalls to protect the network from unauthorized access.
Packet Forwarding Process:
- A packet arrives at the router.
- The router examines the destination IP address in the packet header.
- The router consults its routing table to find the best matching route to the destination network.
- The router forwards the packet to the next hop (another router or the destination host) along the chosen path.
Key components involved in packet forwarding include:
- Interface Cards (NICs): Connect the router to different networks.
- Routing Table: Contains information about network destinations and the best paths to reach them.
- CPU: Processes routing decisions and manages the router's operations.
- Memory: Stores the routing table and other necessary data.