PyNet Labs- Network Automation Specialists
Black Friday Sale - Up to 30% Off
Hurry Up! It's a Limited Period Offer (T&C Apply)
Black Friday Sale - Up to 30% Off
Hurry Up! It's a Limited Period Offer (T&C Apply)

What is IPv6? Its Types and Features

Last Updated : June 18, 2022
what is ipv6

IP stands for Internet Protocol, basically your digital identity over the internet. Every device connected to the internet is located with the help of IP addresses to make communication possible. So, you must be wondering what is IPv6; let's discuss that first. 

What is IPv6?

IPv6 is the latest Internet Protocol version, a network layer protocol that allows communication over the network. It was developed in 1998 by IETF (Internet Engineering Task Force) to overcome the problems IPv4 had. The IPv6 uses 128-bit addressing with an address space of 2^128, which was much bigger than what its predecessor, IPv4, was offering. 

One question always comes up but is never answered: "What happened to IPv5". Let's discuss this first before moving any further. 

What happened to IPv5?

We constantly study the IPv4 and v6, but what about IPv5? 

IPv5 was there in the protocols, but it was not successful. The name of IPv5 was Internet Stream Protocol. Not only IPv4, IPv5, and IPv6, there is a total of 15 versions of IP, and every version was created for a different purpose. 

IPv5 was designed for connection-based communications over IP networks for supporting voice and video. It succeeded in achieving this task, but its downfall was the use 32-bit addresses just like IPv4. 

Coming back to IPv6, let's discuss types of IPv6. 

IPv6 Types

There are three types of IPv6 types, which are as follows: 


A unicast address is used to refer to a single host. It is meant to send data to a single destination. 

RANGE: 2000::/3 (2000 is similar to network ID) 
The unicast address will always start from 2001 

Types of IPv6 UNICAST Addresses:

A. Global Unicast Address (Similar to public IP) 

  • Range of Global Unicast Address 2000::/3 (But we'll start from 2001::/3) 
  • This diagram below is IPv6 anatomy (means IPv6 is made of these) 
what is ipv6


Link-local addresses are designed to address a single link for automatic address configuration, neighbouring discovery, or when no router is present. 

  • It is automatically generated for each IPv6 network interface. 

Note: It is used on an ethernet segment or within a LAN and is like an APIPA Range in IPv4. 

Range: FE80::/10 (here, 10 refers to that we cannot change the starting 10 bits) 

1111 1110 1000 0000 
    F       E        8 

These addresses are not routable. 

C. Unique Local Address 

ULA Addresses can be routed (Except on the public internet). The ULA Address range is FC00::/7. A global authority reserves the first half of the address FC00::/8 for assignment. 

  • Available for local use: the second half of the address range FD00::/8 
  • ULA can be routed but only within one routing domain. 

These are the three types of IPv6 Unicast addresses.  


A multicast address can deliver a packet to a group of destination. A multicast address will deliver any packer sent to it to all hosts that are in that particular group. 

RANGE: FF00::/8 (FF is fixed; we cannot change the value) 

FF02::1 All nodes on the link. (To send a packet to every node, we use this IP, this is a kind of broadcast IP). 


This address is similar to a multicast address. 

These IP addresses are usually assigned on routers and servers, and we can assign the same IP on multiple servers. 
Assigning a unicast address to more than one interface makes a unicast address on anycast address. The closest interface gets the delivery of the packet sent to an anycast address. 
NOTE: This address can be assigned to the host; it can only be assigned on routers or servers. 

Feature of IPv6

Here are the top features of IPv6: 

what is ipv6
  1. An IPv6 is made of 128 bits, divided into eight 16 bits segments or blocks. 
  1. Larger address space (2^128) This is how we find out the total number of addresses in IPv6. 
  1. Simplified Header 
  • The header of IPv4 is 20 bytes and 13 fields. 
  • But in IPv6, the header is 40 bytes, but the fields are only 8. (Less complexity as compared to IPv4) 
  • The increase in size in bytes of IPv6 is because the IPv6 address is total 128 bits, and IPv4 is of 32 bits only. 
  1. End to End Connectivity (No need for NAT) > Every host can directly reach other hosts. 
  1. Auto configuration – it supports both stateful and stateless auto-configuration. 
  • Stateful here means the host is taking IP from the DHCP server (Like Dynamic mode in IPv4). 
  • Stateless here refers to the manual configuration of IP to host (Like static mode in IPv4). 
  1. Fast-forwarding/Routing – all important information is in starting of the header. Therefore, the router takes a quick decision, i.e. (The router can verify the important information in the header so it can make fast decision to forward the data). 
  1. IPsec (Internet Protocol Security) Data will transfer in encrypted form. 
  1. No broadcast. 
  1. Anycast supported. 
  1. Mobility (in earlier times or today, when we switch to another location, the host's IP address also changes because of shortage in IPv4, but IPv6 does not change IP. Your IP will remain constant weather you switch your location or not). 
  1. Smooth Transition 
  • IPv6 isn't backwards-compatible, therefore a complete change may not be feasible to IPv4 towards IPv6. 
  • To get around this issue there are a number of technologies that can be employed to make sure that there is a smooth and seamless change between IPv4 into IPv6. 
  • It includes three technologies: Dual-Stack, Header Translation, Tunnelling 

IPv6 Addresses

IPv6 Addresses are 128-bit alphanumeric values that identify the endpoint device in an IPv6 network. It consists of eight 16-bit fields, with each field separated by a colon.

what is ipv6

This is the basic IPv6 Address format. IPv6 is of 128 bits, having: 
- 8 Segments 
- Hexadecimal 
- Classless 
- No broadcast 
- Backward incompatible (Can't communicate directly with IPv4) 

Interface ID in IPv6:

In an IPv6, the first 64 bits are Network, whereas the last 64 bits are Interface ID. 

  • The address's second half (last 64bits) is always used for interface ID. MAC address is unique 48 bits hexadecimal format. 
  • Interface ID takes advantage of this MAC Address feature. 
  • Host divided MAC address into two 24-bit halves, then inserted 16-bit hex Value FFFE between these two halves. 

IPv6 Compression Rules

There are 5 IPv6 Compressions rules that need to be followed: 

RULE 1: If two blocks contain consecutive zeros, omit them all and replace with double colon sign ": :" 

FFFF: A890: CDEF: 0000: 0000: A001: 00A8: AD00 

FFFF: A890: CDEF :: A001: 00A8: AD00 

If we have 3 consecutive zeros in the continuous format, then also we will use "::"  
The total number of segments in IPv6 is eight. 

RULE 2: "::" must be used to represent the largest number of 16-bit sets of zero as possible. 

FFAA: 0000: 0000: ABCD: 0000: 0000: 0000: AABB 

FFAA: 0000: 0000: ABCD :: AABB 

RULE 3: Remove Leading zeroes 

FFAA: ABCD: 00CD: A789: 0000: 0000: 00AB: 0A79 

1st Output = FFAA: ABCD: 00CD: A789:: 00AB: 0A79 

Now after removing Leading Zeroes 

2nd Output = FFAA: ABCD: CD: A789:: AB: A79 

RULE 4: If there are multiple places where "::" can be used, and the number of Zeroes is the same, Use "::" on the leftmost set of zeroes. 

FFFF: 0000: 0000: AB00: 000A: 0000: 0000: A978 

FFFF :: AB00: 000A: 0000: 0000: A978 – This is according to RULE4 
FFFF:: AB00: A: 0: 0: A978 -- This is according to RULE3 

RULE 5: "::" cannot be used to shorten a single 16 bit set of zeroes. 

These are the IPv6 compression rules. 

IPv6 is an integral part of the CCNA training in which, you get to learn all about IPv6. The CCNA training by PyNet Labs is one of the best training in India. To know more about it, visit the CCNA training page. 

Please share your valuable feedback in the comment section for any suggestions. We will love to hear from your side. If you like this information, you can subscribe to our free newsletter to never miss out on any latest updates. 

Frequently asked questions about IPv6

Question 1 – Should IPv6 be enabled? 

Answer – Disabling IPv6 can cause some window features not to work properly, so it is advisable to always enable it. There are no disadvantages to enabling IPv6, so it is better to keep it enabled. Without enabling IPv6, the internet will be as slow as a snail. 

Question 2 – What does the IPv6 do? 

Answer – IPv6 stands for Internet Protocol version 6, the successor to IPv4. Just like IPv4, IPv6 provides unique IP addresses that are required for communication between the Internet-enabled devices. 

Question 3 – Which is faster IPv4 or IPv6? 

Answer – According to many tests performed by various organizations to compare the speeds of both these technologies, IPv6 always came out superior in terms of speed. IPv6 is the newer and better version of IPv4, so it is faster than IPv4. 

Question 4 – What is the difference between IPv4 and IPv6? 

The main difference between IPv4 and IPv6 is their address size. IPv4 has a 32-bit address, whereas IPv6 uses 128-bit hexadecimal addresses. Another difference is IPv6 has a simple header compared to IPv4 and provides more address space. 

Leave a Reply

Your email address will not be published. Required fields are marked *

linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram