Network Layer Protocols ======================= .. toctree:: :maxdepth: 1 :hidden: :includehidden: ICMPv4 ICMPv6 IGMP ARP LOOP IPv4 IPv6 Network layer protocols provide essential services for addressing, routing, diagnostics, and multicast communication in IP-based networks. .. list-table:: :widths: 15 65 20 :header-rows: 1 * - Protocol - Description - Use Case * - ICMPv4 (Internet Control Message Protocol v4) - Provides diagnostics and error messages in IPv4 networks. *Used for ping, traceroute, and network diagnostics.* - Troubleshooting, path discovery * - ICMPv6 (Internet Control Message Protocol v6) - IPv6 equivalent of ICMPv4 with extended features. *Handles Neighbor Discovery, Path MTU, and IPv6 errors.* - IPv6 diagnostics, auto-configuration * - IGMP (Internet Group Management Protocol) - Manages multicast group membership for IPv4 hosts. *Enables efficient multicast traffic delivery.* - IPTV, streaming, conferencing * - ARP (Address Resolution Protocol) - Resolves IPv4 addresses to MAC addresses within LAN. *Essential for local packet delivery.* - Local delivery in IPv4 networks * - LOOP (Loopback Protocol) - Routes traffic back to the local host (127.0.0.1 / ::1). *Used in local testing and IPC.* - Application testing and diagnostics * - IPv4 (Internet Protocol version 4) - Core IP protocol with 32-bit addressing. *Most widely deployed IP version.* - Internet and enterprise routing, legacy networks * - IPv6 (Internet Protocol version 6) - Next‑generation IP with 128‑bit addressing, built‑in security, and multicast. *Designed for future‑proof routing and addressing.* - IoT, modern Internet, dual‑stack deployments .. tab-set:: .. tab-item:: ICMPv4 (Internet Control Message Protocol v4) **RFC:** RFC 792 **Main Features:** - Echo request/reply for reachability checks - Error reporting for unreachable hosts and TTL expiry - Used by traceroute and Path MTU discovery **Use Cases:** - Ping and route analysis - Diagnosing unreachable endpoints and latency issues **Alternative Protocols:** - ICMPv6 – For IPv6 diagnostics - SNMP – Device and service monitoring - TCP Keepalive – Application-level reachability .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about ICMPv4:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`ICMPv4 Version&RFC Details ` * :ref:`ICMPv4 Basic Setup on Ubuntu using IPv4 ` * :ref:`ICMPv4 Protocol Packet Details ` * :ref:`ICMPv4 Usecases ` * :ref:`ICMPv4 Basic Features ` * :ref:`ICMPv4 Feature : Diagnostic Tools Support ` * :ref:`ICMPv4 Feature : Message Types and Codes ` * :ref:`ICMPv4 Feature : Error Reporting ` * :ref:`ICMPv4 Feature : Lightweight Protocol ` * :ref:`ICMPv4 Feature : No Reliability Mechanism ` * :ref:`ICMPv4 Feature : Control and Informational Messages ` * :ref:`ICMPv4 Feature : Stateless Operation ` * :ref:`ICMPv4 Feature : Security Considerations ` * :ref:`Reference links ` .. button-link:: ./ICMPv4.html :color: primary :shadow: :expand: Jump to "ICMPv4" .. tab-set:: .. tab-item:: ICMPv6 (Internet Control Message Protocol v6) **RFC:** RFC 4443 **Main Features:** - Supports IPv6 Neighbor Discovery and path discovery - Router and prefix advertisement/reductions and redirects - Error messaging for IPv6 operations **Use Cases:** - IPv6 host reachability testing - Auto-configuration and router discovery - Path and route debugging for IPv6 **Alternative Protocols:** - ICMPv4 – IPv4 equivalent - SNMP – Network health monitoring .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about ICMPv6:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`ICMPv6 Version&RFC Details ` * :ref:`ICMPv6 Basic Setup on Ubuntu using IPv6 ` * :ref:`ICMPv6 Protocol Packet Details ` * :ref:`ICMPv6 Usecases ` * :ref:`ICMPv6 Basic Features ` * :ref:`ICMPv6 Feature : Integrated with IPv6 ` * :ref:`ICMPv6 Feature : Supports NDP ` * :ref:`ICMPv6 Feature : Error and Informational Messages ` * :ref:`ICMPv6 Feature : Multicast-Based Communication ` * :ref:`ICMPv6 Feature : Security-Aware Design ` * :ref:`ICMPv6 Feature : Extensible Message Format ` * :ref:`ICMPv6 Feature : No Fragmentation Support ` * :ref:`ICMPv6 Feature : Rate Limiting ` * :ref:`Reference links ` .. button-link:: ./ICMPv6.html :color: primary :shadow: :expand: Jump to "ICMPv6" .. tab-set:: .. tab-item:: IGMP (Internet Group Management Protocol) **RFCs:** RFC 2236 (v2), RFC 3376 (v3) **Main Features:** - Enables IPv4 hosts to join/leave multicast groups - Controls multicast traffic delivery on LANs - Works with multicast routers to manage flows **Use Cases:** - IPTV streaming - LAN conference and gaming multicast - Multicast-aware routing **Alternative Protocols:** - MLD – IPv6 multicast protocol - PIM – Protocol‑Independent Multicast for routing .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about IGMP:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`IGMP Version&RFC Details ` * :ref:`IGMP Basic Setup on Ubuntu using IGMP ` * :ref:`IGMP Basic Setup on Ubuntu using IGMP ` * :ref:`IGMP Protocol Packet Details ` * :ref:`IGMP Usecases ` * :ref:`IGMP Basic Features ` * :ref:`IGMP Feature : Multicast Group Management ` * :ref:`IGMP Feature : Efficient Bandwidth Usage ` * :ref:`IGMP Feature : Host-Router Communication ` * :ref:`IGMP Feature : Dynamic Membership ` * :ref:`IGMP Feature : Version Compatibility ` * :ref:`IGMP Feature : Query and Report Mechanism ` * :ref:`IGMP Feature : Leave Group Notification ` * :ref:`IGMP Feature : Support for Source Filtering ` * :ref:`IGMP Feature : Minimal Overhead ` * :ref:`IGMP Feature : Integration with Multicast Routing Protocols ` * :ref:`Reference links ` .. button-link:: ./IGMP.html :color: primary :shadow: :expand: Jump to "IGMP" .. tab-set:: .. tab-item:: ARP (Address Resolution Protocol) **RFC:** RFC 826 **Main Features:** - Resolves IPv4 addresses into MAC addresses via LAN broadcast - Maintains ARP cache for efficient forwarding - Operates at Layer 2 for Layer 3 traffic delivery **Use Cases:** - Mapping IPv4 to MAC addresses on Ethernet - Required by routers and hosts for LAN communication **Alternative Protocols:** - NDP – IPv6's ARP equivalent - Proxy or static ARP – For subnet bridging or manual mapping .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about ARP:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`ARP Version&RFC Details ` * :ref:`ARP Basic Setup on Ubuntu using IPv4 ` * :ref:`ARP Basic Setup on Ubuntu using IPv6 ` * :ref:`ARP Protocol Packet Details ` * :ref:`ARP Usecases ` * :ref:`ARP Basic Features ` * :ref:`ARP Feature : IP to MAC Resolution ` * :ref:`ARP Feature : Dynamic Addressing Mapping ` * :ref:`ARP Feature : Broadcast-Based Requests ` * :ref:`ARP Feature : Caching Mechanism ` * :ref:`ARP Feature : Gratuitous ARP ` * :ref:`ARP Feature : Stateless Protocol ` * :ref:`ARP Feature : No Authentication ` * :ref:`ARP Feature : Essential for IPv4 Networks ` * :ref:`Reference links ` .. button-link:: ./ARP.html :color: primary :shadow: :expand: Jump to "ARP" .. tab-set:: .. tab-item:: LOOP (Loopback Protocol) **RFCs:** RFC 1122 (IPv4), RFC 4291 (IPv6) **Main Features:** - Returns traffic to local host using loopback addresses - Enables internal testing and IPC without external networking **Use Cases:** - Testing local servers and applications - Verifying internal TCP/IP stack operation **Alternative Protocols:** - UNIX domain sockets - Virtualized private loop interfaces .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about LOOP:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`LOOP Version&RFC Details ` * :ref:`LOOP Basic Setup on Ubuntu using IPv4 ` * :ref:`LOOP Basic Setup on Ubuntu using IPv6 ` * :ref:`LOOP Protocol Packet Details ` * :ref:`LOOP Usecases ` * :ref:`LOOP Basic Features ` * :ref:`LOOP Feature : Local Communication ` * :ref:`LOOP Feature : Virtual Interface ` * :ref:`LOOP Feature : Reserved Address Space ` * :ref:`LOOP Feature : No External Routing ` * :ref:`LOOP Feature : Protocol Testing ` * :ref:`LOOP Feature : Service Isolation ` * :ref:`LOOP Feature : IPV4 and IPV6 Support ` * :ref:`LOOP Feature : Application Development ` * :ref:`LOOP Feature : Performance Benchmarking ` * :ref:`LOOP Feature : System Health Monitoring ` * :ref:`Reference links ` .. button-link:: ./LOOP.html :color: primary :shadow: :expand: Jump to "LOOP" .. tab-set:: .. tab-item:: IPv4 (Internet Protocol version 4) **RFC:** RFC 791 **Main Features:** - 32-bit addressing (IPv4) - Connectionless, best-effort packet delivery - Handles fragmentation, TTL, and checksums - Backbone of TCP/UDP traffic worldwide **Use Cases:** - Global internet and LAN routing - Legacy device support and embedded systems **Alternative Protocols:** - IPv6 – Next-generation protocol - IPX, ATM/Frame Relay – Older legacy alternatives .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about IPv4:** .. button-link:: ./IPv4.html :color: primary :shadow: :expand: Jump to "IPv4" .. tab-set:: .. tab-item:: IPv6 (Internet Protocol version 6) **RFC:** RFC 8200 **Main Features:** - 128-bit addressing for scalable IP - Simplified headers and built-in IPsec - Multi‑ and anycast support - Uses IPv6 Neighbor Discovery instead of ARP **Use Cases:** - Modern internet infrastructure and IoT - Dual-stack networks - Secure routing and auto-configuration **Alternative Protocols:** - IPv4 – Still in widespread use - 6LoWPAN – IPv6 on constrained IoT networks .. panels:: :container: container pb-4 :column: col‑lg‑12 p‑2 :card: What You Will Learn in This Section **Let us learn more about IPv6:** .. button-link:: ./IPv6.html :color: primary :shadow: :expand: Jump to "IPv6"