Home > IPv6 Tutorial

IPv6 Tutorial

June 24th, 2011 Go to comments

Internet has been growing extremely fast so the IPv4 addresses are quickly approaching complete depletion. Although many organizations already use Network Address Translators (NATs) to map multiple private address spaces to a single public IP address but they have to face with other problems from NAT (the use of the same private address, security…). Moreover, many other devices than PC & laptop are requiring an IP address to go to the Internet. To solve these problems in long-term, a new version of the IP protocol – version 6 (IPv6) was created and developed.

IPv6 was created by the Internet Engineering Task Force (IETF), a standards body, as a replacement to IPv4 in 1998. So what happened with IPv5? IP Version 5 was defined for experimental reasons and never was deployed.

While IPv4 uses 32 bits to address the IP (provides approximately 232 = 4,294,967,296 unique addresses – but in fact about 3.7 billion addresses are assignable because the IPv4 addressing system separates the addresses into classes and reserves addresses for multicasting, testing, and other specific uses), IPv6 uses up to 128 bits which provides 2128 addresses or approximately 3.4 * 1038 addresses. Well, maybe we should say it is extremely extremely extremely huge :)

IPv6 Address Types

Address Type Description
Unicast One to One (Global, Link local, Site local)
+ An address destined for a single interface.
Multicast One to Many
+ An address for a set of interfaces
+ Delivered to a group of interfaces identified by that address.
+ Replaces IPv4 “broadcast”
Anycast One to Nearest (Allocated from Unicast)
+ Delivered to the closest interface as determined by the IGP

A single interface may be assigned multiple IPv6 addresses of any type (unicast, anycast, multicast)

Note: There is no broadcast address in IPv6

IPv6 address format


x:x:x:x:x:x:x:x – where x is a 16 bits hexadecimal field and x represents four hexadecimal digits.
An example of IPv6:

There are:
+ 8 groups of 4 hexadecimal digits.
+ Each group represents 16 bits (4 hexa digits * 4 bit)
+ Separator is “:”
+ Hex digits are not case sensitive, so “DBCA” is same as “dbca” or “DBca”…

IPv6 (128-bit) address contains two parts:
+ The first 64-bits is known as the prefix. The prefix includes the network and subnet address. Because addresses are allocated based on physical location, the prefix also includes global routing information. The 64-bit prefix is often referred to as the global routing prefix.
+ The last 64-bits is the interface ID. This is the unique address assigned to an interface.

Note: Addresses are assigned to interfaces (network connections), not to the host. Each interface can have more than one IPv6 address.

Rules for abbreviating IPv6 Addresses:

+ Leading zeros in a field are optional

2001:0DA8:E800:0000:0260:3EFF:FE47:0001 can be written as


+ Successive fields of 0 are represented as ::, but only once in an address:

2001:0DA8:E800:0000:0000:0000:0000:0001 -> 2001:DA8:E800::1

Other examples:
– FF02:0:0:0:0:0:0:1 => FF02::1
– 3FFE:0501:0008:0000:0260:97FF:FE40:EFAB = 3FFE:501:8:0:260:97FF:FE40:EFAB = 3FFE:501:8::260:97FF:FE40:EFAB
– 0:0:0:0:0:0:0:1 => ::1
– 0:0:0:0:0:0:0:0 => ::

IPv6 Addressing In Use

IPv6 uses the “/” notation to denote how many bits in the IPv6 address represent the subnet.

The full syntax of IPv6 is


+ ipv6-address is the 128-bit IPv6 address
+ /prefix-length is a decimal value representing how many of the left most contiguous bits of the address comprise the prefix.

Let’s analyze an example:
2001:C:7:ABCD::1/64 is really
+ The first 64-bits 2001:000C:0007:ABCD is the address prefix
+ The last 64-bits 0000:0000:0000:0001 is the interface ID
+ /64 is the prefix length (/64 is well-known and also the prefix length in most cases)

In the next part, we will understand more about each prefix of an IPv6 address.

Comments (50) Comments
Comment pages
  1. uday
    March 8th, 2014

    Good summary of IPv6 !!

  2. Reza
    April 9th, 2014

    Thanks. Good tutorial on IPv6.

  3. Salam
    April 17th, 2014

    Very Nice, to understand about IPv4

  4. Osama Bin Laden
    May 3rd, 2014

    Thank you

  5. Abdulazeez
    May 6th, 2014

    nice one and cool.God bless you.

  6. fatema anwar
    May 7th, 2014

    really helpful …thanx

  7. Sadrul
    May 12th, 2014

    Thanks……..really helpful..!!!!!!

  8. AT
    May 14th, 2014

    great tutorial…easy to understand

  9. Boudcha
    May 22nd, 2014

    Than you it is veru usefull tuturial

  10. Saroj Dongol
    May 31st, 2014

    Thanks you so much . it clear my doubt about ipv6

  11. Anonymous
    June 9th, 2014

    Excelente, muy acertado el tutorial

  12. sepehr
    July 20th, 2014


  13. Anonymous
    July 23rd, 2014

    Hello everyone here,

    I was wondering if any one has the CCNA CBT Nuggets.
    Especially IPv6 part.
    Feel free to send them to my email address:arwa.alansary@yahoo.com

    Also, I am going to have my exam on August 14. If you have any useful resources, please let me know.


  14. hadii
    August 9th, 2014

    thank you for the explanation. am ok now.

  15. Kim Jong-un
    August 19th, 2014

    this website is gold! thanks alot

  16. wondering
    October 21st, 2014

    Are any of these ipv6 questions on the test

  17. Abbas Ali
    October 27th, 2014

    I want to ask something that if a person gets prepared for CCNA and CCNP but have n’t give the Industry paper,Can he appear for CCIE?

  18. sanjeev yaliballi
    October 29th, 2014

    nice one…

  19. hafeez
    December 15th, 2014

    very good concept

  20. rocknolds
    February 20th, 2015

    does this mean that when we are assigning static IPv6 to our computer/host for example, we can cause IP address conflict to possibly another host that is located on another place or organization?

  21. afzal
    April 14th, 2015

    comprehensible examples!

  22. Anonymous
    June 18th, 2015

    i have a questions 314

  23. G.S.G
    June 23rd, 2015

    Thanks for this information. It’s help me a lot.

  24. Onésimo
    August 7th, 2015

    Very usefull summary

  25. ANGY
    September 24th, 2015


  26. Anonymous
    September 29th, 2015

    Very nice tutorial

  27. amoskbc
    October 14th, 2015

    ipv6;kindly help,,basic concepts

  28. Steptabs
    October 15th, 2015

    Nice one,very informative

  29. Anonymous me
    December 1st, 2015

    Thanks for this 9tut.. You rock! Much appreciated

  30. masoom siddiqui
    December 14th, 2015

    thanks team for inform me

  31. Anonymous
    February 29th, 2016

    nice and good content.

  32. Anonymous
    March 17th, 2016

    Can each interface have more than one IPv6 address?

    In this tutorial, it is mentioned that:

    “Note: Addresses are assigned to interfaces (network connections), not to the host. Each interface can have more than one IPv6 address.”

  33. Anonymous
    April 28th, 2016

    i want to learn the subneting with ipv6 address, please help me. thanks

  34. Cris
    May 18th, 2016

    Excellent tutorial on IPv6. Thank you…

  35. arsh
    May 26th, 2016

    very good. Could someone can send me icnd 100-101 dumps. arshadnazir at gmail dot com

  36. adex
    May 27th, 2016

    i dont undrstand ipv6 explanation

  37. adex
    May 27th, 2016

    pls any help bcos i score 44% on it at my ccna

  38. adex
    May 27th, 2016

    am ccna certified since 2015 but i dont know where i can apply it for work

  39. ASM
    August 31st, 2016

    if you need help in OSPF Ipv6 , please check out this Link http://asmed.com/cisco-ccna-ospf-ipv6-configuration/

  40. Gobba
    March 7th, 2017

    Very nice posts…love your tutorialsssssssss

  41. the timeshare
    April 8th, 2017

    Apple previously has Rhapsody as an application, which is a perfect start off, nevertheless it is previously hampered via the lack of ability towards shop locally upon your iPod, and incorporates a dismal 64kbps little bit price. If this improvements, then it will rather negate this comfort for the Zune, yet the Ten music for each thirty day period will nonetheless be a significant plus inside of Zune Pass’ want.


  42. Man Bravender
    April 15th, 2017

    This is the best search system in the planet


  43. Hubert Kiernan
    April 19th, 2017

    Very nice post. I absolutely like this website. Keep it up!


  44. Marian Roscoe
    April 22nd, 2017

    Very nice blog post . I certainly love your site. Keep it up!


  45. Merrilee Sudak
    April 27th, 2017
  46. Anonymous
    May 7th, 2017

    hey guys …. if anyone has latest dumps for ccna 200-125. please please send it on {email not allowed}. I would be really helpful. thank you

  47. Nugo
    May 13th, 2017

    Short, dense and clear. Thx a lot!!

  48. Zekma
    May 28th, 2017

    Clear and easy to understand

  49. Edra Wordlow
    August 23rd, 2017

    Love those little stars makeup! Do more of it! Love you Amandani


Comment pages
Add a Comment