IPv6 quadruples the number of network address bits from 32 bits (in IPv4) to 128 bits, which provides more than enough globally unique IP addresses for every networked device on the planet.
The primary motivation for IPv6 is the need to meet the demand for globally unique IP addresses. Large IPv6 Address Space for Unique Addresses Other available features include stateless autoconfiguration and an increased number of multicast addresses. IPv6 supports widely deployed routing protocols such as Routing Information Protocol (RIP), Integrated Intermediate System-to-Intermediate System (IS-IS), Open Shortest Path First (OSPF) for IPv6, and multiprotocol Border Gateway Protocol (BGP). IPv6 prefix aggregation, simplified network renumbering, and IPv6 site multihoming capabilities provide an IPv6 addressing hierarchy that allows for more efficient routing. The simplified IPv6 packet header format handles packets more efficiently. The larger IPv6 address space allows networks to scale and provide global reachability. The architecture of IPv6 has been designed to allow existing IPv4 users to transition easily to IPv6 while providing services such as end-to-end security, quality of service (QoS), and globally unique addresses. Further RFCs describe the architecture and services supported by IPv6. IPv6 is described initially in RFC 2460, Internet Protocol, Version 6 (IPv6) Specification, issued by the Internet Engineering Task Force (IETF). After extensive discussion it was decided to base IPng on IP but add a much larger address space and improvements such as a simplified main header and extension headers. IPv6 was proposed when it became clear that the 32-bit addressing scheme of IP version 4 (IPv4) was inadequate to meet the demands of Internet growth. IP is a packet-based protocol used to exchange data, voice, and video traffic over digital networks. IPv6, formerly named IPng (next generation), is the latest version of the Internet Protocol (IP). Information About IPv6 Addressing and Basic Connectivity
IPv6 packets are transparent to Layer 2 LAN switches because the switches do not examine Layer 3 packet information before forwarding IPv6 frames.Restrictions for Implementing IPv6 Addressing and Basic Connectivity To access Cisco Feature Navigator, go to An account on is not required.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document. For the latest feature information and caveats, see the release notes for your platform and software release.
Your software release may not support all the features documented in this module. The user can enhance basic connectivity functionality by configuring support for AAAA record types in the Domain Name System (DNS) name-to-address and address-to-name lookup processes, and by managing IPv6 neighbor discovery. IPv6 traffic forwarding can be enabled globally, and Cisco Express Forwarding switching for IPv6 can also be enabled. Implementing basic IPv6 connectivity in the Cisco software consists of assigning IPv6 addresses to individual device interfaces. The unlimited address space provided by IPv6 allows Cisco to deliver more and newer applications and services with reliability, improved user experience, and increased security. Internet Protocol version 6 (IPv6) expands the number of network address bits from 32 bits (in IPv4) to 128 bits, which provides more than enough globally unique IP addresses for every networked device on the planet. Feature Information for IPv6 Addressing and Basic Connectivity.Example: Hostname-to-Address Mappings Configuration.Example: Dual-Protocol Stacks Configuration.Example: IPv6 Addressing and IPv6 Routing Configuration.Configuration Examples for IPv6 Addressing and Basic Connectivity.Configuring IPv6 Addressing and Enabling IPv6 Routing.