3. Network Layer
| Protocol Name | Description | Common Usage |
|---|---|---|
| IP (Internet Protocol) | The fundamental protocol for routing packets across networks. It defines addressing, packet format, and routing. | Used for internet communication (IPv4 and IPv6), enabling end-to-end connectivity. |
| IPv4 (Internet Protocol version 4) | The fourth version of IP, using 32-bit addresses, allowing for approximately 4.3 billion unique addresses. | Still widely used in internet communications, despite the transition to IPv6. |
| IPv6 (Internet Protocol version 6) | The successor to IPv4, using 128-bit addresses, enabling a vastly larger address space. | Used for modern internet communication, especially as IPv4 addresses become exhausted. |
| ARP (Address Resolution Protocol) | Resolves IP addresses to MAC addresses within a local network to facilitate data link communication. | Used in Ethernet and other LAN technologies for address mapping. |
| ICMP (Internet Control Message Protocol) | A protocol used for sending error messages and operational information about network conditions, such as unreachable destinations. | Used by utilities like ping and traceroute to diagnose network issues. |
| IGMP (Internet Group Management Protocol) | Used to manage group memberships for multicast groups in IP networks. | Essential in multicast communication for managing group memberships and distributing data. |
| NAT (Network Address Translation) | A method for remapping IP addresses, typically used to allow multiple devices on a local network to share a single public IP address. | Used in home routers and firewalls to provide internal networks with internet access. |
| IPSec (Internet Protocol Security) | A suite of protocols designed to secure IP communications by encrypting and authenticating IP packets. | Commonly used in VPNs to provide secure data transmission over the internet. |
| MPLS (Multiprotocol Label Switching) | A protocol for routing and forwarding packets in high-performance networks, where packets are assigned a label to expedite the forwarding process. | Used by ISPs and large-scale enterprise networks for traffic management and efficient routing. |
| Routing Protocols (RIP, OSPF, BGP, EIGRP, IS-IS) | Protocols like RIP, OSPF, BGP, EIGRP, and IS-IS help networks route packets efficiently between different routers. | Used for determining optimal routes within networks, including internet routing with BGP and internal routing with OSPF and EIGRP. |
| L3VPN (Layer 3 Virtual Private Network) | A VPN solution that allows organizations to extend their private IP network across public infrastructure using tunneling protocols like MPLS. | Commonly used by enterprises to securely connect multiple sites across the internet or private networks. |
| SLIP (Serial Line Internet Protocol) | A simple protocol used for sending IP packets over serial connections, typically for dial-up internet access. | Mostly obsolete today but used in early internet dial-up connections. |
| PPP (Point-to-Point Protocol) | A protocol used to establish a direct connection between two network nodes, often used in dial-up and VPN connections. | Used for point-to-point connections, such as in DSL or VPNs, for encapsulating data and providing error detection. |
| Ethernet (IEEE 802.3) | A widely used protocol in LANs that defines the physical and data link layer standards but also includes network layer functionalities for routing. | The most common LAN technology for wired networks, supporting both IPv4 and IPv6. |
| 6LoWPAN (IPv6 over Low-Power Wireless Personal Area Networks) | A protocol for transmitting IPv6 packets over low-power, low-bandwidth networks like wireless sensor networks. | Used in IoT applications, particularly in environments where power and bandwidth are limited. |
| RARP (Reverse Address Resolution Protocol) | A protocol used to map a known MAC address to an IP address. The reverse of ARP. | Rarely used today, but was used in early network bootstrapping processes. |
| L2TP (Layer 2 Tunneling Protocol) | A tunneling protocol used for VPNs, typically paired with IPsec for encryption. | Used in VPNs to provide secure tunneling for data transmission. |
| GRE (Generic Routing Encapsulation) | A tunneling protocol that encapsulates network layer packets into point-to-point connections. | Commonly used in tunneling for virtual private networks or to connect disparate network segments. |
| HDLC (High-Level Data Link Control) | A bit-oriented synchronous data link layer protocol that can be used for point-to-point connections. | Used in WAN technologies for leased-line data transmission. |
Explanation of Layer:
- Network Layer (Layer 3): Primarily responsible for packet forwarding, routing, and addressing. The protocols defined at this layer ensure that data packets can travel across multiple networks and reach their intended destination using proper addressing mechanisms.
These protocols form the foundation for enabling communication across diverse network environments, ranging from local area networks (LANs) to wide area networks (WANs) and the internet.