IPv6

1.   IPv6 (Internet Protocol version 6) is a set of specifications from the Internet Engineering Task Force (IETF) that's essentially an upgrade of IP version 4 (IPv4). The basics of IPv6 are similar to those of IPv4. Devices can use IPv6 as source and destination addresses to pass packets over a network, and tools like ping work for network testing as they do in IPv4, with some slight variations.

2.   The most obvious improvement in IPv6 over IPv4 is that IP addresses are lengthened from 32 bits to 128 bits. This extension anticipates considerable future growth of the Internet and provides relief for what was perceived as an impending shortage of network addresses.

3.   IPv6 address types:

·     Unicast: one to one

·     Multicast: one to many

·     Anycast: one to nearest communication.

4.   Unicast address types:

·     Global unicast (are globally routable, same as IPv4 public addresses)

Range (2000:: /3)

·     Link local (to communicate in same subnet. Confined to a link only.)

It is assigned automatically.

Starts with FE80:: /64 (first 64 bits represents network part). Host part will be derived by using eui-64(extended unique id).

·     Unique local (same as private IPs)

Starts with FC00::/

5.   Multicast address:

Range:  FF00::/8

6.   By using Anycast address, we can assign same IP on multiple servers. You get reply from the nearest server available.

7.   IPv4 and IPv6 are not backward compatible. To make communication possible between both version we use some techniques:

·     Dual stack: configure both version at both ends.

·     Tunnel between both ends.

8.   IPv6:

·     xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

·     IPv6 is divided into 8 fields.

·     Each field is of 16 bits.

·     Each field ranges from 0-F.

·     No concept of subnet mask.

·     We use CIDR value to identify network part and host part.

9.   Shorthand notations of IPv6:

·     0001=1, 0011=11, 0111=111(can remove zeroes)

·     1000=1000(can’t remove zeroes)

·     :0000:=:0:

·     1111:0000:0000:0000:0000:0000:0000:2222=1111::2222

·     :: can be used once.

10.                Eui-64

·     eui-64 is used to automatically derive 64 bits host part in link local IPv6 address.

·     First 64 bits will be FE80.

·     For last 64 bits, it will use MAC address of the interface. MAC address is of 48 bits. Still we are short of 16 bits. So MAC address is splitted into 2 parts, 24 bits and 24 bits. In between both 24 bits 16 bits FFFE is added.

11.                IPv6 configuration commands:

·     To enable IPv6 on any interface

Router(config)#interface fastEthernet 0/0

Router(config-if)#ipv6 enable

·     To enable IPv6 routing

Router(config)#Ipv6 unicast-routing