IPv6

IPv6 Protocol Virtual Laboratory

ECE 422 Data Communications & Networking,  Electrical & Communication Engineering

01 Introduction to IPv6

Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.

Key Motivations for IPv6

  • IPv4 address exhaustion (232 vs 2128 addresses)
  • Improved multicast routing support
  • Simplified header format for faster processing
  • Built-in security (IPsec) and auto-configuration

IPv6 Address Format

Full Address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Compressed: 2001:db8:85a3::8a2e:370:7334
* Zero compression (::) can only be used once per address

02 IPv6 Packet Header Structure (40 Bytes Fixed)

Version
4 bits
Traffic Class
8 bits
Flow Label
20 bits
Payload Length
16 bits
Next Header
8 bits
Hop Limit
8 bits
Source Address
128 bits (16 bytes)
Destination Address
128 bits (16 bytes)

Comparison with IPv4

Feature IPv4 IPv6
Header Size 20-60 bytes Fixed 40 bytes
Checksum Header checksum None (handled by L2/L4)
Fragmentation Routers & hosts Only source hosts

Address Types

Unicast One-to-one
Multicast (ff00::/8) One-to-many
Anycast One-to-nearest
Broadcast Not supported

03 Address Scopes and Special Addresses

🌍

Global Unicast

2000::/3

Routable addresses globally unique. Equivalent to IPv4 public addresses.

🏢

Unique Local (ULA)

fc00::/7

Private addresses for local networks. Similar to RFC1918 but with global uniqueness probability.

🔗

Link-Local

fe80::/10

Auto-configured on every interface. Used for neighbor discovery and local network communication.

Special Multicast Addresses

ff02::1 All nodes (link-local)
ff02::2 All routers (link-local)
ff02::1:ffxx:xxxx Solicited-node multicast

Loopback & Unspecified

::1 Loopback (localhost)
:: Unspecified address