Tecnología Electrónica

IPv4 Address Purpose: Device Identification & Packet Routing

An **IPv4 address** (32-bit, dotted-decimal e.g., 192.168.1.1) serves two core functions in internetworking:

1. Host Identification

  • Uniquely identifies a network interface (host) within an IP network.
  • Enables end-to-end addressing: source IP + destination IP in every packet header.
  • Public IPs = globally unique (managed by IANA/RIRs). Private IPs (10/8, 172.16/12, 192.168/16) = locally unique, NATed to public.

2. Routing & Forwarding

  • Routers use destination IP's **network prefix** (via subnet mask/CIDR) to decide next hop.
  • Hierarchical allocation (ISP → customer → subnet) enables aggregation — keeps global routing table manageable (~900k routes).
  • Fragmentation/reassembly, TTL, TOS/DSCP, options — all in IPv4 header.

Limitations Driving IPv6

  • 4.3 billion addresses exhausted (2011 IANA pool).
  • NAT breaks end-to-end, complicates P2P, VoIP, IoT.
  • No built-in security, mobility, QoS.

IPv4 remains dominant (90%+ traffic) via NAT, CGNAT, and IPv6 transition tech (dual stack, MAP-E, 464XLAT).

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