Ccna certification， i pv6 features

1. CCNA Certification:IPv6 Features
Main Feature of IPv6
IPv6 address a lot concerns and issues that are faced today in using IPv4. Cisco CCNA Certification
requires that a candidate must have a general overview of IPv6 and what new features it brings
into the world of networking. Here we will go through some of the features of Internet Protocol
Version 6 (IPv6).
The main feature of IPv6 are described in the sections below
Larger Address Space
IPv6 addresses are 128-bits long which gives us a theoretical address space of 3.4 x 1038
addresses, like IPv4 some address space is reserved for special purpose but still there is a huge
number of public routable addresses.
Aggregation
A larger address space allows for large address allocations to ISPs and Organization. This allows
them to use a single prefix for the entire network making summarization easy and flexible which
turn promotes efficient and scalable routing.
New Improved Header Format
Optional and non-essential fields are removed from the IPv6 Header and are moved the
Extension Header that is placed after the IPv6 Header. Fewer fields of fixed lengths mean Header
overhead is minimized and processing performance is improved. Another significant
enhancement is that all routers in a path do need to do checksum recalculation for an IPv6 Packet
instead error detection is handled by data-link layer technologies checksums of the end-to-end
connection at transport layer.
Figure 1 shows an IPv6 Header followed by Extension Header.

2. Allocation
IPv6 addresses are composed of two parts, 64-bit Network Prefix and 64-bit host part. The IPv6
address allocation follows a generally acceptable assignment policy as shown in figure 1. This
allows for an efficient, hierarchical, and summarizable routing infrastructure.
Easy Address Assignment Methods
IPv6 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

3. router discovery messages, a host can also determine the addresses of routers, additional
addresses, and other configuration parameters.
Built-in Security
IPSec is built into IPv6 unlike IPv4 in which it is optional. IPSec requirement is mandatory in IPv6
Protocol Suite Implementation. IPv6 networks have potentially more end-to-end security because
of IPSec availability on all nodes.
Extensibility
New futures for IPv6 can be added through the use of Extension Headers. At present there are
various Extension Headers specified for QoS, Security, Mobility and Routing purposes.
Mobility
Mobility is built in to IPv6 which allows any node to use Mobile IP. Mobility is achieved using
Mobility Extension Headers.
Better Quality of Service Support
IPv6 Header includes a new field called Flow Label that allows routers to identify and provide
special handling for packets that belong to a particular flow. This field allows for easier
identification of traffic without doing any tricks even when the packet payload is encrypted with
IPSec.
Neighbor Discovery Protocol
Neighbor 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 Determination
Transition
The transition options supported by IPv6 to transition from IPv4 are another key feature of the
protocol. Many Transitions mechanism are available for different scenarios. They are mentioned
below
Dual-Stack
Tunneling IPv6 over IPv4 networks
Protocol Translation
Within each option are various different techniques to support transition. A few tunneling
mechanism are mentioned below
Static GRE Tunnels

4. 6to4 Tunnels
ISATAP
Automatic IPv4-Compatible IPv6 Tunnels
These 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/