IPv6 internet protocol in COMPUTER NETWORK CS2302 Anna Univeristy Question

IPv6

IPv6, formerly named IPng (next generation).

It is the latest version of the Internet Protocol (IP).

 IP is a packet-based protocol used to exchange data, voice, and video traffic over digital networks.

IPv6 quadruples the number of network address bits from 32 bits (in IPv4) to 128 bits.

By being globally unique, IPv6 addresses inherently enable global reachibility and end-to-end security for networked devices.

The flexibility of the IPv6 address space reduces the need for private addresses and the use of Network Address Translation (NAT) thus, IPv6 enables new application protocols that do not require special processing by border routers at the edge of networks.

IPv6 Address Formats

IPv6 addresses are represented as eight groups of four hexadecimal digits separated by colons (:) in the format:

2001:0DB8:7654:3210:FEDC:BA98:7654:3210

2001:0DB8:0:0:8:800:200C:417A

IPv6 Basic IP Header

The IPv6 protocol defines a set of headers, including the basic IPv6 header and the IPv6 extension headers. The following figure shows the fields that appear in the IPv6 header and the order in which the fields appear.

 

·         Version – 4-bit version number of Internet Protocol = 6.

·         Traffic class – 8-bit traffic class field.

·         Flow label – 20-bit field.

·         Payload length – 16-bit unsigned integer, which is the rest of the packet that follows the IPv6 header, in octets.

·         Next header – 8-bit selector. Identifies the type of header that immediately follows the IPv6 header. Uses the same values as the IPv4 protocol field.

·         Hop limit – 8-bit unsigned integer. Decremented by one by each node that forwards the packet. The packet is discarded if the hop limit is decremented to zero.

·         Source address – 128 bits. The address of the initial sender of the packet.

·         Destination address – 128 bits. The address of the intended recipient of the packet. The intended recipient is not necessarily the recipient if an optional routing header is present.

IPv6 Extension Headers

The following IPv6 extension headers are currently defined:

·         Routing – Extended routing, such as IPv4 loose source route

·         Fragmentation – Fragmentation and reassembly

·         Authentication – Integrity and authentication, and security

·         Encapsulating Security Payload – Confidentiality

·         Hop-by-Hop options – Special options that require hop-by-hop processing

·         Destination options – Optional information to be examined by the destination node

IPv4	IPv6
IPv4 addresses are 32 bit length.	IPv6 addresses are 128 bit length.
IPSec support is only optional.	Inbuilt IPSec support.
Fragmentation is done by sender and forwarding routers.	Fragmentation is done only by sender.
No packet flow identification.	Packet flow identification is available within the IPv6 header using the Flow Label field.
Checksum field is available in header	No checksum field in header.
Options fields are available in header.	No option fields, but Extension headers are available.
Address Resolution Protocol (ARP)is available to map IPv4 addresses to MAC addresses.	Address Resolution Protocol (ARP)is replaced with Neighbor Discovery Protocol.
Internet Group Management Protocol (IGMP) is used to managemulticast group membership.	IGMP is replaced with MulticastListener Discovery (MLD)messages.
Broadcast messages are available.	Broadcast messages are not available. Instead a link-local scope all-nodes multicast address is used for broadcast.
Manual configuration (Static) of IP addresses or DHCP (Dynamic configuration) is required toconfigure IP addresses.	Auto-configuration of addresses is available.

Advantages of IPv6

1)More Efficient Routing

2)More Efficient Packet Processing

3)Directed Data Flows

4)Simplified Network Configuration

5)Support For New Services

6)Security

 

Subnetting

A subnetwork, or subnet, is a logically visible subdivision of an IP network.[1] The practice of dividing a network into two or more networks is called subnetting.

 

DHCP(Dynamic Host Configuration Protocol)

DHCP allows a computer to join an IP-based network without having a pre-configured IP address.

DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network.

In basic terms, the DHCP lease process works as follows:

1.    A network device attempts to connect to the Internet.

2.    The network requests an IP address.

3.    The DHCP server allocates (leases) the network device an IP address, which is forwarded to the network by a router.

4.    DHCP updates the appropriate network servers with the IP address and other configuration information.

5.    The network device accepts the IP address.

6.    The IP address lease expires.

7.    DHCP either reallocates the IP address or leases one that is available.

8.    The network device is no longer connected to the Internet.

9.    The IP address becomes an available address in the network pool of IP addresses.

To set up DHCP, you basically need a DHCP-supported client (at least one) and router, and a DHCP server. The client is a computer or other device on a network that requires an IP address and or other network configuration information. The router functions as a forwarding (or routing) agent of IP address requests from the DHCP server. 

 

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