ipv4 vs ipv6 which is better

There are two different IP addressing schemes used on the Internet. They are, IPv4 (also known as just IP) and IPv6. No need to worry about IPv1-3 and IPv5, they are non-existent.let’s discuss about ipv4 vs ipv6 which is better

ipv4 vs ipv6 which is better

IPv4 is the older of the two and more widely used. I do not have a figure, but if I were to guess, I’d say that 90% of the devices that are currently connected to the Internet are using IPv4 addressing. Although IPv4 has been in existence for many decades and for the most part has served us well, it is currently exhausted. IPv4 utilizes a 32-bit addressing scheme which yields about 4.3 billion addresses. As of February, 2011, ICANN, the authority that gives out new IP addresses, announced that they no longer  have  new IPv4 addresses to give out. This was anticipated for a long time and hence IPv6 addressing was created several years ago to deal with this exact issue and a few other things. Although, IPv6 is designed to produce more IP addresses than we’ll ever need in our lifetime, I’ll let time to be the judge of that.

ipv4 vs ipv6 which is better

Most of the Cisco networking equipment support concurrent addressing in both IPv4 and IPv6 format. This is also true for some major PC and other IP device (PDA, Cell phone, etc.) manufacturers and Operating Systems such as Windows 7 and Linux. From ground up, IPv6 was designed to co-habit with the existing IPv4, so the migration from IPv4 to IPv6 becomes easier.

One may ask, “What’s the point of spending time in learning IPv4 addressing, since it’s going to be phased out soon?” It would be phased out for sure, because it has to, but not very soon. We expect to see IPv4 still dominating the Internet for at least 7 to 10 more years before it is completely phased out. Also, without a good working knowledge of IPv4, it would be impossible to pass the “CCNA1: Network Fundamentals” course (1st of 4 CCNA courses), let alone the CCNA certification exam. All CCNA courses (CCNA1-CCNA4) are based on IPv4.  In addition, companies will be looking for network engineers with IPv4 knowledge for many years to come.

ipv4 vs ipv6 which is better

A Typical Home Addressing: Before learning IPv4 addressing, lets first look at how a typical home addressing works here in America. For simplicity, I’ve used the word “home,” but it could be an office, an apartment or a farm, etc. This will be used as an analogy to describe how IPv4 addressing works.

Example 1:

Cisco Systems, Inc.

170 West Tasman Dr.

San Jose, CA 95134


The address above has, more or less, five (5) identifiers*, and they are, Name, Street, City, State & Country. Traditionally, we’ve been writing an address following the format shown above because we are told to do so by the post office. This makes it easier for the postman and, especially, the postal scanners (computers) to sort out the mails for proper destinations. Although the address above is written from top-to-bottom, it would be safe to assume that the sorting machines actually read the address from bottom-to-top. Bottom being more general and towards the top being more specific address identifiers.

To be able to make my analogy of home addressing to the IPv4 addressing, let me write the identifiers of the above address in a single line as shown below, separating each identifier by a dash. Also, to have some fun with it, lets just call it the dashed representation of a typical home address, where the traditional address identifiers are written in a single line, from left-to-right, left being more general and the right being more specific.

ipv4 vs ipv6 which is better

Example 2: A dashed representation of a typical home address

USA – CA 95134 – San Jose – 170 West Tasman Dr.* – Cisco Systems, Inc.

Note: The ‘*’ is not part of the address, it is there just to be able to make a point later.

Looking at this dashed addressing, it would be safe to conclude that,  “USA – San Jose – CA 95134 – 170 West Tasman Dr. -” is the general part of the address and “Cisco Systems, Inc.” is the most specific part, the final destination of the mail. Therefore, we can say that in example 2, four (4) identifiers (from left to right) was used to represent the general part of the address, which leaves the 5th identifier to be the most specific part of the address, the final destination. Now that we had fun with it, lets look at another address shown below, which has four (4) identifiers instead of five (5).

ipv4 vs ipv6 which is better

Example 3: Another example of a dashed representation of a typical home address

CA 92128 – San Diego – 12001 Bing Crosby Avenue* Unit #2 – Willie Smith

The address above indicates that Willie Smith lives in Unit #2 of the building labeled as 12001 Bing Crosby Dr. Since there could be more than one person by the name Willie Smith living in 12001 Bing Crosby Dr., Unit #2 has to be included as a part of the most specific address, the 4th identifier. Therefore, in example 3 above, about 2-2/3 identifiers represent the general part of the address and rest 1-1/3 identifier represents the most specific part of the address.

One may ask, “What is the big fuss about noticing the general part and the most specific part of an address?” This is where I need your patience to pay attention to how we (humans) think and how it differs from computers’ thinking. In example 2, we started to read the address from left-to-right, then we took a split second pause at the asterisk, before concluding that Cisco Systems, Inc. is the final  destination. In example 3, we repeat the same process, but this time include Unit #2, the last 1/3 part of the 3rd identifier, before concluding that Unit #2 & Willie Smith is the final destination. In example 3, we also ignored the fact that USA is missing from the beginning of the address. We process this information with ease because we are trained to do so. Also, what helps our brain is the type setting, the font, casing, spaces, dashes, periods, numbers and other queues like the two-letter state abbreviation followed by a 5-digit ZIP code, etc.

Note: The asterisk shown above is not part of the address, it is there only to show exactly where our brain may take a pause to separate the two main parts of an address.

Now, hold on to your seats cowboys and cowgirls, and try to solve the following brain teasers.

Example 4a:


Example 4b:


In the examples above, I’ve removed all the spaces, dashes and periods, and changed all alphabets to small letters. You may still be able to use your perceptions to figure out who the address belongs to. This may not have been too difficult because you possess the power of human perception. But, “Who is there to say that the address in example 4a does not belong to ‘sco systems inc’?” Now, lets try to solve another puzzle shown below.

ipv4 vs ipv6 which is better

Example 5:


Can you tell me who the above address belongs to? Example 5 displayed the same address as in example 4a, but in a binary format, a language that only computers communicate in. But here is the dilemma. Since computers do not possess, or at least not most computers, the same kind of perceptions as we humans do, how would it know that the address belongs to “cisco systems inc” and not to “sco systems inc” or “isco systems inc” or “drcisco systems inc” or something else which may be very meaningless. As a matter of fact, the computer would not know unless we tell it how to separate the general part from the most specific part of an address. Very shortly, we’ll see how we instruct the computer to do that.

So far, we have established the fact that a home address is divided into two(2) specific parts. First being the general part and the 2nd being the specific part, the person (thing) the address belongs to. We are also faced with a challenge, that is, the computer must know how to decipher the general part of an address from its specific part, so there are no confusions.

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