Let’s move on to IPv6. I told you on the latest post that the need for private IPv4 is to assign those devices to the communication that does not need internet service or if it requires, NAT concept will follow. IP address conservation is the target of that concept. Ipv4 was designed in the 1980’s time and the designers wasn’t able to predict that networking concept will grow up fast. Public IP addresses are distributed by IANA to different parts of the world. The thing here is that almost all devices can have an IP address and be part of a certain network. If we will project the population of the world by 2020 and multiply it by at least three devices in the world, and also consider those private, multicast and broadcast IP address which are reserved, this require IPv4 demand. IPv6 will take part to cover the IPv4 address demand.
IPv6 is a 128-bit logical address with 8 slots in hextet / quartet form separated by colon. I would be a good idea if I will give you an example:
ipv4 address 192.168.1.1/ 24
ipv6 address–> 2102:ABFE:3FCD:021E:0002:1234:4AEB:0BDE/64
Yup! this is a long format. Let us try to analyze each part of the IPv6 address. The highlighted blue quartet which is 2102 represents 16 bits. Since we are in hexadecimal, each character represents 4 bits. Since there are four characters in the 2102 quartet it represents 16 bits. So if each quartet represents 16 bits and there are 8 quartets in IPv6 address logical format, we conclude that there are 128 bits in IPv6 address.
I underlined the first 4 quartets of IPv6 address to present that those part represents the network. The CIDR notation serves as an indication of the network. The bloody red /64 states that the first 64 bits of this IPv6 address represent the network. In IPv6 world, the network part maybe termed as “prefix”
Since we configure IP address, let me clarify here that we will have abbreviation rules to follow to abbreviate IPv6 address. Yup, we can abbreviate IPv6 address. First, it will be convenient for us CCNA wannabe’s , also, it will lessen the burden at work if we deal with less numbers.
RULES for IPv6 addressing Abbreviations:
1.Omit leading zero’s
Condition A: Omit leading zero’s as it is for those quartet with at least one nonzero hexadecimal
Condition B: Pure-zero quartet must have a single zero
2.Use double colon ONLY ONCE to replace long string of ZERO’s
Rule #1 2001:1:1010:0:0:0:CAFE:FEED–> we omit the leading zero’s, we applied condition A and condition B
We applied condition A for quartet 0001 it is the thing I told that possess at least one zero. Just omit leading zero’s as it is.
We applied condition B for the green portion of the ipv6 address because those are pure zero quartets
Rule #2 2001:1:1010::CAFE:FEED
2001:1:1010::CAFE:FEED is the best simplified answer
Applying Rule #1 Condition B and Condition A
Applying rule #2
Remember that for rule#2, we can only use it once and since our goal is to abbreviate the IP address and both sides share the length of zero’s, we can have two options to abbreviate that IPv6 address.
The answer for this is–> 2001::AB:0:0:12B0
; We then conclude that Rule #1 is just easy to follow but for Rule #2, we must be firm with the rule that we use double colon ONLY ONCE and to replace the longest the set of long zero quartet. Always remember that our goal is to abbreviate the IPv6 address. We can have another answer which is –>2001:0:0:0:AB::12B0 but why settle for the longer one?
IPv6 subnetting almost follows the same rule for Ipv4 addressing
I’m sorry for my paint skills, but we have to realize how characters must be presented by bits in subnetting, so we conclude that we need a network that represents 35 bits for this example. The first quartet/hextet represents the first 16 bit, the first and 2nd hextet represent the 32nd bit and the last three bits can be taken from the first hexadecimal of the third hextet.So the increment takes place at the first bit of the third hextet as well.
What’s the process for the increment thingy for Ipv6 address?
The increment ranges from 1, 2,4 and 8 . To make it simple, where your subnet falls is what will your increment per subnet be.
So to subnet 2001:ABC:0000::/35, we will have
2001:ABC:A000::/35 and so on.