Cisco Introduction to Networks Lecture: Module 12 - IPv6 Addressing

Overview

• Discussion on IPv4 issues leading to IPv6 development
• IPv6 addressing scheme explained
• IPv6 address representation and types
• Configuration: static and dynamic addressing for IPv6
• IPv6 multicast addresses
• Subnetting in IPv6

IPv4 Issues

• IPv4 addresses are limited and running out
• IPv6 was developed as a successor with 128-bit address space
• Transition from IPv4 to IPv6 is necessary due to internet growth and IoT
• NAT (Network Address Translation) used to manage IPv4 limits

IPv6 and IPv4 Coexistence

• Both will coexist; transition may take decades
• Migration techniques: Dual Stack, Tunneling, Translation (NAT64)
  • Dual Stack: IPv4 and IPv6 run simultaneously
  • Tunneling: Encapsulates IPv6 packets in IPv4
  • Translation: NAT64 for communications between IPv4 and IPv6

IPv6 Address Representation

• 128 bits long, written in hexadecimal
• Not case-sensitive (e.g., 0db8 can be lowercase or uppercase)
• Rules for Representation:
  • Omit Leading Zeros: Simplify notation by removing leading zeros
  • Double Colon Rule: Replaces contiguous zeros, can be used once

IPv6 Address Types

• Unicast: Identifies a single interface
• Multicast: Sends packet to multiple destinations
• Anycast: Shared by multiple devices; nearest receives packet
• No broadcast addresses as in IPv4

IPv6 Prefix Length

• Indicates network portion
• Can range from 0 to 128; recommended is /64

Types of IPv6 Unicast Addresses

• Global Unicast Address (GUA): Similar to IPv4 public address; globally routable
• Link Local Address (LLA): Communicate on local link, not routable
• Other types: Loopback, unspecified, unique local, embedded IPv4

Unique Local Addresses (ULAs)

• Range from FC00::/7 to FDFF::/7
• Used for local addressing; not globally routed

IPv6 Global Unicast Address Structure

• Global Routing Prefix: ISP assigned, varies by policy
• Subnet ID: Identifies subnets within a site
• Interface ID: Equivalent to host portion in IPv4

IPv6 Link Local Address (LLA)

• Enables communication on the same link only
• Must be present on every IPv6 enabled interface

Configuring IPv6 Addresses

• Static GUA Configuration: IPv6 address command on router
• Dynamic Addressing:
  • Router Solicitation (RS) and Router Advertisement (RA): For discovery and configuration
  • Slack, Slack with Stateless DHCP, Stateful DHCP
  • EUI-64 vs Random Generation: Methods for interface ID

Multicast Addresses

• Prefix: FF00::/8
• Types: Well-known, Solicited Node
• Well-known: All nodes and all routers multicast groups

Subnetting IPv6 Networks

• Designed with subnetting in mind
• Subnet ID field between global routing prefix and interface ID

Conclusion

• IPv4 exhaustion necessitates IPv6 transition
• IPv6 provides larger address space and improved features

Study Recommendations:

• Understand address representation rules
• Distinguish between unicast, multicast, and anycast
• Familiarity with configuring GUAs and LLAs
• Note the transition techniques and their uses

Practical Exercises:

• Ensure hands-on practice with Cisco labs if possible