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IPv6 |
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Many things have changed since Arpanet. If we look to the 30 or 40 years back, we may be startled to see how much has changed in such a small span of time (and in such a fast way). The first thing that strikes our mind about this change is the "speed of the Internet": The first "backbone" had a bandwidth in 2 Kbps. Nowadays, let alone a scientist, this speed does not suffice for an "end-user" who simply plays backgammon over Internet. Fortunately, many things have changed. When we use the word "backbone", we mean to say "massive" networks with a bandwidth of 10 Gigabytes per second. We have mutliplied our speed 5-10 thousand times in the course of the time. Another glaring example is the number of people using the computer networks. This example illustrates the current situation in Turkey as well: 10 years ago, METU seems to be the only institution using the Internet; however today, there is nearly no university left which is not connected. Moreover, not only the universities, the home users has increased rapidly in number as it is the case the whole world and in Turkey. In Turkey, the pioneers to welcome the innovations have always been the universities; many advancements either technologically or in any other field has always been achieved and implemented firstly in the universities. Briefly, the Internet, a phenomenon, which was being used by only a few people 40 years ago, has now become the “network of networks” that has been shared by everybody and that embrace the world globally. There’s not much room for everyone on Internet It would be nice to take it easy and say "Let them use it, Internet has room for everybody”; unfortuately, this is not the case. There’s not much room for everyone on Internet. For sure, the Internet is one of the most demeocratic mediums that exercise no segregation among people. Yet, what we mean by “room” or space on Internet is merely a protocol that was not envisaged in its original designs to encompass so much people. This protocol which was named after Internet (or which became the source for the name of Internet), namely "Internet Protocol", is basically a number allocation system that assigns a number to everyone. Every person, who will connect to the Internet or is already connected, has an IP number by default -to put it in more technical terms- has an "IP address" by default. If you’d like to have a space on Internet, the first thing you are to do is to find an IP adress from somewhere. For instance, if you are attending a University, most probably your department will assign you one. Then, how on earth your department has obtained that IP address from? Most probably, they have obtained the IP number from that university’s office for Information Technology Services. But, how did University’s Office for IT Services obtained that IP number? An institution such as a University’s IT Services Office may have obtained the IP numbers from a number of places; but, were it an IT Services Office within Turkey, most probably the numbers would be taken from RIPE. RIPE is an organisation which principally and specifically provides space on Internet to the people. It achieves this mission by distributing IP address blocks to the institutions. As one can easily guess, the existent IP blocks are apportioned worldwide. But then, what do I imply by “There’s not much room for everyone on Internet”? The answer of this question lies inbetween the concepts of the structure of the IP addresses and the methods of their distribution: Currently, the IP addresses are 32 bytes. In binary system, it corresponds to 232 number of IP addresses. If we leave out some IP addresses that have specific purposes, there are approximately 4 billions of IP addresses in the world. We can easily conclude that this not enough to connect the total of the world population to the Internet. The reason is not the fact that each person on earth demands to connect to the Internet. Indeed, the main factor for the insufficiency of the IP addresses is that IP addresses were distributed lavishly in the course of the time. This drawback is the result of the initial design. We do not need to go very far to give an example to this. In METU, IP addresses start with the following number cluster 144.122; this is the 16 byte block that is assigned to METU. It corresponds to 216 = 65536 number of IP addresses. This means that it is possible to assign 2 IP addresses to per person in METU. It is possible to assert that every member of METU can have two computers one day. However; it is also possible to assert that practically, this will not happen in 20 or 30 years to come. The current practice causes more than half of the IP addresses to remain idle, and the Internet infrastructure does not allow them to be used by others. This is the case in the whole world; a significant part of the 4 billions of IPs stay idle and it is not diffibult to guess that they cannot be used by others who need them. Many organizations solve this problem by using the "IP blocks that are reserved for special purposes". With this attitude that somehow contradicts with the spirit of fairness of Internet, these organizations had to use virtual IPs to connect the computers to the Internet. Though this situation violates the rules of fair play, people were quick to make up an excuse for such a deed. They called it NAT (Network Address Translation). What NAT actually provides is one connection to the Internet; over this single connection each computer that is assigned virtual IPs connects to the Internet as well.That single connection owns the real IP address. It is obvious that one single IP number is asigned to many computers. The Internet of our Children In the course of the history, it may be said that Internet is one of the greatest innovations that transformed the whole world. Especially, it greatly facilitated accessibility to the information as compared to the former times when there was no Internet. It is a well known fact that information is enriched, if it is shared; therefore, it is essentially important to share the knowledge with everyone. So, it is equally important that there is room to everyone on Internet. Then, it is felicitous to ask "Why don’t we change the current IP addressing system, and replace it with another one?". That is exactly the solution to the problem, and it is already worked upon. A new IP addressing system has been developed to eliminate the drawback.. The Internet protocol of our children is a next generation IP system that is called IPng. It aims to fix all the problems of the Internet Protocol, principally the insufficiency of the IP addresses. To differentiate between the two systems, they are named with their version numbers. The system currently used is called IPv4 and the new system is called IPv6. It is a good question to ask "Then, what happened to? Why it skips IPv5 and becomes IPv6?". For further details about this concern, please read the following quote from http://www.oreillynet.com/pub/wlg/3316: "... 5 was already given to something else. In the late 1970's, a protocol named ST (The Internet Stream Protocol) was created for the experimental transmission of voice, video, and distributed simulation. Two decades later, this protocol was revised to become ST2 and started to get implemented into commercial projects by groups like IBM, NeXT, Apple, and Sun. Wow did it differ a lot. ST and ST+ offered connections, instead of its connection-less IPv4 counterpart. It also guaranteed QoS. ST and ST+, were already given that magical '5'." Those who would like to read IPv6 from its official standard can find it on RFC2460. IPv4 dead, Hail to IPv6! Technically speaking, IPv6 differs fundamentally and structurally from IPv4. The first thing to mention as different from IPv4 is that IPv6’s address size was increased four times from 32 bytes to 128 bytes. This fundamentally erased the drawback of address insufficiency. Moreover, this solution was designed for future use as well. A 128-byte-address corresponds to 340.282.366.920.938.463.463.374.607.431.768.211.456 pieces of IPv6 addresses. This means that avagadro number of IPv6 addresses fall per square meter. There will be no need to fear that IP addresses will not suffice since you will be able to request an IPv6 address even for your toothbrush. If you feel that a number cluster such as 144.122.199.93 is dull and meaningless, then, get yourself acquainted with the following IPv6 address: 2001:0A98:BA90:7AC0:0000:0000:0000:0066 Indeed, we should be thankful because the address is not represented by decimal notation. For if it was represented by decimal notation, the number would be as follows: 32.1.10.152.186.144.122.192.0.0.0.0.0.0.0.66 Moreover, you can replace the zeros with :: when it is represented by hexadecimal number system: 2001:0A98:BA90:7AC0::66 . Here, you should be careful about the fact that you can do it only for one group of zeros; this means that you can not write an IPv6 address such as 2001:0A98:0000:0000:0030:0000:0000:0066 as 2001:0A98::30::66. This is simply because there are two groups of zeros. You can either write it as 2001:0A98::30:0:0:66 or as 2001:0A98:0:0:30::66. This shows that some IPv6 addresses can be represented in more than one ways. See it from the bright side. You can now have an IPv6 address ending with your birthdate: 2001:0A98:FFFF::1974:12:22. You should not be surprised when you see that the IPv6 address of www.metu.edu.tr domain is assigned as 2001:0A98:FFFF::1956:11:15. If it is still too complex for you, you can have the computer to assign itself automatically an IPv6 address with the new autoconfiguration feature. Fortunately, these issues will bother only the network and system administrators. (and those people who are curious about these technical aspects.) This is, of course, not the only difference and innovation that IPv6 introduces. For example, significant changes have been made on the header part of each IPv6 packets. These changes will enable the packets to be delivered faster and they will facilitate building of more secure communication infrastructures. Moreover, it will promote the audial and visual communication over Internet. There’s good news for the people complaining about the slowness of Internet: Some parts from the header of IPv4 have been removed because they were complicating things. The header is now fixed in length so that time will not be wasted on the routers anymore. The time saved here will enable the packets to be delivered faster. Moreover, the intelligence agents will not be pleased about the header parts such as AH and ESP, because they enable secure encrypted data communication between the ends. AH and ESP sections aim to support IPSec protocol that encrypts all the network traffic between two ends. Due to the increasing traffic, the quality of live broadcasting, telephone communication, or teleconferencing over Internet have been reduced. However, there is an option that prioritizes the delivery of packets of such important applications. One should simply add "this traffic is prioritized" label on the header section of IPv6. It is possible to save important applications on Internet, such as an international visual conference, from the blockage of the restless children playing Counterstrike within campus network. Moreover, the multicast addresses are more well-defined on IPv6 protocol that it seems people will cause minimum traffic while applying firewall on live broadcast applications. Are we ready? Let’s transition to IPv6! We had better talk about the requirements needed to transition the current system to a network with IPv6 addresses. If we evaluate the situation on the part of the end user, there is not much to be done. On a network that is rendered compatible with IPv6 protocol by the system/network administrators, the maximum requirements to be carried out for the end user are to change the progams used currently with the new versions. The users of Linux operating system should make sure that they have enabled the IPv6 support on their kernels. Mozilla and Opera enable users to navigate Internet sites that support IPv6. With programs such as lftp,you can transfer files supporting IPv6. From the very beginning, the releases of Openssh have been supporting the IPv6 endeavours. The users of Windows operating system, as it is the case with every innovation introduced, are to renew their operating systems to be able to access the features that IPv6 introduces. There is no IPv6 support before Windows XP operating system and it is still experimental on Windows XP. It seems that IPv6 support cannot be fully realized for Windows operating system users before Windows 2003 is actually released. If you would like to find out about which clients/servers support IPv6, take a look at the following address: http://www.deepspace6.net/docs/ipv6_status_page_apps.html. IPv6 is the only solution to maintain the Internet’s current ubiquitous status. For example, the only way for most of the far east countries, especially China, to connect to Internet is to use IPv6 addresses. And they actually connect to Internet with this method. In fact, far east countries put pressure on Europe to transition their system to IPv6 protocol. One of the reasons of this pressure is the strain caused by the limited IPv6 addresses. To better understand another reason, an issue that was taken for granted should be accentuated once again: IPv6 does indeed provide more than enough IP addresses. The number is so much that every electronical device that is able to communicate in one way or another can be assigned an IPv6 address. It is not that difficult for the producers of the devices to use that IP number as a model number of the product. Practically, this naturally leads us to the fact that a new communication standard should be accepted. To make things more clear, for instance, it will be possible to communicate your peripheral devices (such as keyboard, mouse, printer, screen etc.) through a network among the devices with your computer. Or, you will be able to connect your mobile phone to your computer in a more standardized way because they will both have IPv6 addresses. When we think about the end users, it is very likely and possible that electronic devices at home that support IPv6 can speak and communicate with each other or with a central computer in a standard way. From fire safety systems to refrigerators, from automobile security systems to microwave owens, it is possible to manage all the electronic devices from your mobile phone. One day you may find yourself purchasing a toothbrush that supports IPv6. The technical innovations the system will bring are abundant in mumber. Though we will gain much from those innovations, it is not easy to quit IPv4 abruptly and start using IPv6. This may prove a deed as pulling the plug of Internet, so to speak. If we do not want be without Internet, we had better use them simultaneously and compatibly for a while and we should experience a sound transition period. Hopefully, the end users are not going to be affected much from the transition process to IPv6. Most of the job and dirty work is going to be carried out by network administrators. This transition period is going to take some considerable amount of time. It will take many years to completely abolish IPv4 system. Thanks to IPv6 that many of the shortcomings of this transition period is taken into consideration and plans were made in advance during the design phase of the IPv6. The addresses that should be used during the transition period such as IPv4m-mapped-IPv6 address or IPv4-compatible IPv6 have already taken their place in IPv6 protocol. Then, when will the transition period end? The best answer to this question can be given by those who read this article actually. In Europe and America, many of the networks have already lauched their IPv6 support. For example, "there are currently 6Bone sites in many countries in Asia, Australia, Europe, and North America. All of the 6Bone sites are shown on the 6Bone topology map. (Source: http://playground.sun.com/pub/ipng/html/ipng-main.html). In Turkey, TÜBÝTAK - ULAKBÝM (http://www.ulakbim.gov.tr) can establish connection to the networks that support IPv6 abroad through UlakNet over Geant (http://www.dante.net/geant/) port. If the University, to which you are a member of, applies to Ulakbim and demands an IPv6 address block, the procedures to attain that IPv6 address block can be started. The following are some of the main IPv6 addresses that you may want to look at to get more information: Linux: IPv6 (http://www.bieringer.de/linux/IPv6/)
After taking a look at these sites, remember to google the Internet, too: Looking forward to see you in a CISN that supports IPv6 J Tufan KARADERE |
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