CCNA Certification:IPv6 FeaturesMain Feature of IPv6IPv6 address a lot concerns and issues that are faced today in using IPv4. Cisco CCNA Certificationrequires that a candidate must have a general overview of IPv6 and what new features it bringsinto the world of networking. Here we will go through some of the features of Internet ProtocolVersion 6 (IPv6).The main feature of IPv6 are described in the sections belowLarger Address SpaceIPv6 addresses are 128-bits long which gives us a theoretical address space of 3.4 x 1038addresses, like IPv4 some address space is reserved for special purpose but still there is a hugenumber of public routable addresses.AggregationA larger address space allows for large address allocations to ISPs and Organization. This allowsthem to use a single prefix for the entire network making summarization easy and flexible whichturn promotes efficient and scalable routing.New Improved Header FormatOptional and non-essential fields are removed from the IPv6 Header and are moved theExtension Header that is placed after the IPv6 Header. Fewer fields of fixed lengths mean Headeroverhead is minimized and processing performance is improved. Another significantenhancement is that all routers in a path do need to do checksum recalculation for an IPv6 Packetinstead error detection is handled by data-link layer technologies checksums of the end-to-endconnection at transport layer.Figure 1 shows an IPv6 Header followed by Extension Header.
AllocationIPv6 addresses are composed of two parts, 64-bit Network Prefix and 64-bit host part. The IPv6address allocation follows a generally acceptable assignment policy as shown in figure 1. Thisallows for an efficient, hierarchical, and summarizable routing infrastructure.Easy Address Assignment MethodsIPv6 has three assignment methods Static DHCPv6 (Stateful) Autoconfiguration (Stateless)An IPv6 host can configure a link-local address for each interface automatically. By using ICMPv6
router discovery messages, a host can also determine the addresses of routers, additionaladdresses, and other configuration parameters.Built-in SecurityIPSec is built into IPv6 unlike IPv4 in which it is optional. IPSec requirement is mandatory in IPv6Protocol Suite Implementation. IPv6 networks have potentially more end-to-end security becauseof IPSec availability on all nodes.ExtensibilityNew futures for IPv6 can be added through the use of Extension Headers. At present there arevarious Extension Headers specified for QoS, Security, Mobility and Routing purposes.MobilityMobility is built in to IPv6 which allows any node to use Mobile IP. Mobility is achieved usingMobility Extension Headers.Better Quality of Service SupportIPv6 Header includes a new field called Flow Label that allows routers to identify and providespecial handling for packets that belong to a particular flow. This field allows for easieridentification of traffic without doing any tricks even when the packet payload is encrypted withIPSec.Neighbor Discovery ProtocolNeighbor Discovery Protocol uses ICMPv6 messages to perform various functions such as Stateless Auto-configuration Router Discovery Prefix Discovery Address Resolution Neighbor Unreachability Detection Link MTU Discovery Duplicate Address Detection Next Hop DeterminationTransitionThe transition options supported by IPv6 to transition from IPv4 are another key feature of theprotocol. Many Transitions mechanism are available for different scenarios. They are mentionedbelow Dual-Stack Tunneling IPv6 over IPv4 networks Protocol TranslationWithin each option are various different techniques to support transition. A few tunnelingmechanism are mentioned below Static GRE Tunnels
6to4 Tunnels ISATAP Automatic IPv4-Compatible IPv6 TunnelsThese rich features of IPv6enable easy deployment, migration and operation of IPv6 networks.More Notes: If you wanna read more news about Cisco and Cisco equipment, you can visit:http://blog.router-switch.com/