Implementation And Transition To Ipv6

Published Date: 02 Nov 2017

1.Introduction

2.IP version 4

3.IP version 4 addressing

4.Comparison to IP version 4 and version 6

5.Transition to IP version 6

6.IP version 6 implementation

7.Dual stack

8.Tunneling

9.Conclusion

10.References

To IP and beyond

Introduction

The transmission control protocols/internet protocol( TCP/IP) was developed for the U.S. department of defense’s advanced research project agency network ( ARPANET) by the people called Vinton Clef and Bob Kahn in 1974. TCP/IP protocol is the transport/network layer used on the internet. It is also the world’s most popular network protocol used by almost 70 percent of all backbone, metropolitan and wide area networks. In 1998 TCP/IP moved past IPX/SPX as the most common protocol used in LANs. The foundation for today’s internet was the result of the DARPANET. It was born from the dream to build a network that will continue to function even if a segment was lost. In the late 1960s universities have grow their interest about building a network connecting their all research systems. An large number of universities were now able to afford and use computers as part of their education and research. Computers act a vital part of the research. Research institutes wanted to share their issues and efforts between different part of the universities. Also there was a idea about to work in combined with other universities by sharing data. ARAPANET was first used in 1971 and provide the use of IP’s predecessor, the network control protocol or NCP.

Now the standards are available, testing and implementation on a wide scale was necessary. In 1980 ARPANET started converting systems to TCP/IP .in 1983 ,ARPANET was divided into two different networks ; MILNET for military research and ARPANET for continuing the current way of research. In 1983 it was also decided by ARPANET that all systems connected to ARPANET use TCP/IP.

Ipv4 became more finalized as the official RFC’s for TCP/IP v4 were documented. RFC’s 760 and 761 were written in 1980 as outlines for the new protocols, which were TCP and IP. RFC ‘s 791,792 and 793 were published in 1981 by DARPANET. The initial TCP/IP RFC’s were instrumental in IPv4 ‘s further development worldwide. A documented standard allowed other research organizations and universities to begin testing and implementing on one set of protocols.

TCP/IP allows reasonably efficient and error free transmission. Because it performs error checking, it can send large files across sometimes unreliable networks with great assurance that the data will arrive uncorrupted.TCP/IP is compatible with a variety of data link protocols, which is one reason for it’s popularity. As the name implies , TCP/IP has two parts. TCP is the transport layer protocol that link the application layer to the network layer. It performing segmenting breaking the messages it receives from the application layers into small segments or packets , numbering them ,ensuring that each packet has reliably delivered, and putting them back together into one message at the destination. IP is the network layer protocol and performs addressing and routing.IP software is used at each of the intervening computers through which the message passes, it is IP that routes the message to the final destination. The TCP software only needs to be active at the sender and the receiver ,because TCP is involved only when data comes from or goes to the application layer.

Uses of new technologies have extended IPv4’s lifetime. Network address translation(NAT) and classless inter domain routing (CIDR) are the two key elements that have allowed for the extension of IP addresses in IPv4. NAT allows multiple systems on a private network to share one public IP address. NAT can also help prevent unwanted access from outside the private network. CIDR is a type of addressing within IPv4 that makes use of 13 to 27 prefixes. The prefix designates how many of the starting address bits are used to identify the private network. The remaining bits identify the local host.CIDR and NAT were crucial in making the IPv4 address pool last as long as it has .the expansive need for CIDR,NAT and BGP has resulted in overly large routing tables. The extensive routing tables result in unnecessary administrative overhead in building ,maintaining and replacing routing equipment. As these technologies are no longer needed in IPv6routing, table size will decrease dramatically.

Comparison of IPv4 and IPv6

While Ipv4 and ipv6 are similar in much of their basic frame work but there are many differences in the addresses between IPv4 and IPv6. The idea below an Ip address for both versions of IP.

IPv4 address example – 125.12.3.65

IPv6 address example – 2145;00D5;2F3B;0000;0000;00FF;EF00;98F3

Removing zeros can also reduce the IPv6 address. Zeros can be removed when they are leading in and with in any 16 bit block. The address from the previous example can be reduced using this to the following representation. Note that in the example the block of EF00 does not lose its zeros because they are at the end of the block.

Ipv6 address with leading zeros removed- 2145;D5;2F3B;0;0;FF;EF00;98F3

Compressing zeros can further reduce in ipv6 address. A block of zeros within a 16 bit block can be removed. The blocks of zeros are then represented by double colons . For example the ipv6 multicast address of FF02;0000;0000;0000;0000;0000;0000;0002 can be reduced to FF02::2 using compression ( double colons)

Ipv6 address with compressed address 2145;D5:2F3B;;FF;EF00;98F3

An ipv4 address has 32 bits whereas an ipv6 address contains 128 bits. The 128 bits in an ipv6 address are divided between the network and host addresses. There are 64 bits for the network address and 64 bits for the host address. Due to the larger address space ,the number of available addresses jumps into 4,294.967,296 in ipv4 to 3.4 multiply by ten to the power thirty eight in ipv6. Ipv6’s address is also separated using a different format.ipv4 uses a dotted decimal and ipv6 uses a colon hex format. The larger address space allows for clearer addressing and routing . it is also provide for multiple interfaces per host and multiple addresses per interface.

The ipv6 address space supports three types of address; unicast,multicast and anycast. Ipv6 multicast addressing absorbs the role of ipv4’s broadcast addresses, which is no longer present. The largest change is the introduction of the anycast address. the anycast addressing allows multiple nodes to be assigned the same anycast address, when packets are sent to this address routing decides which node is closest to the source and routes the traffic to it. Anycast addresses can be useful in setting up mirror websites, with different physical locations being accessible through the same anycast address . a user trying to access this site would then be routed to the closest site, result a better experience .

Addressing enhancements result in reduced administrative overload. The teaming of ipv6 neighbor discovery and address auto configuration provide hosts to operate in any location without any special support. Renumbering is made easier, resulting in less manual attention by support and network administrators. renumbering also makes transition from ISP to ISP or network packets to packet much easier and potentially seamless. Stateless and stateful address configuration assist in making ip configuration and planning easier. Stateless configuration works without a DHCP server , while stateful is a configuration that has a DHCP server present.

With a new addressing scheme comes a new way of handling name resolution through DNS. The DNS changes required to support ipv6 are specified in RFC 1886. As part of the interim transition from ipv4 to ipv6 ,it is possible to register an ipv6 for DNS and the consumer would prefer to use ipv6 DNS. The figure below shows a WHOIS lookup in which the domain has an ipv6 address and is found through ipv4 DNS.

Security is a key feature of ipv6 . ipv6 is primarily focused on improved security, which makes it popular as data security becomes more and more of a hot topic in all areas of IT. There are many standard and required security features within ipv6 without having to make changes to applications. Among the improved security features is packet signing to handle authentication. Data confidentially through encryption helps aid security within ipv6.ipv6 includes an end to end security model that is designed to protect DHCP,DNS and IPv6 mobility. While IPv6’s improvements in security does not make IP invulnerable from attacks, it is certainly a positive addition.

The ip routing experience differs with the implementation of ipv6. Smaller routing tables result in more efficient routing and less overhead through faster computation. The routing structure makes use of a hierarchical structure that is also more efficient. Ipv6 brings major changes to the IP header.IPv6’s header is far more flexible and contains fewer fields , with the number of fields dropping from 13 to 8. Fewer header fields result in a cleaner header format and quality of service that was not present in ipv4.IP option fields in headers have been replaced by a set of optional extensions. The efficiency of ipv6’s header can be seen by comparing the address to header size. Even through the ipv6 address is four times larger than the ipv4 address, the header is only twice as large. Priority traffic , such as real time audio or video, can be distinguished from lower priority traffic through a priority field. The images below show the difference in the headers. Red designates fields in the ipv4 header that are no longer present in the ipv6 header.

Implementation and transition to IPv6

Ipv6 implementation is an on going process. some analysts make comparisons between the potential shortfall of ipv4 addresses and the potential problems feared with year 2000/Y2K problems . although there is no specific date to fear, it is important that testing and integration begin. With specifications in place by 1995,testing and implementation of ipv6 was begun. The task of transitioning to ipv6 is full of challenges. Large scale transitions require a high level of flexibility in the protocol stack, software and hardware supporting and using it. A successful migration to ipv6 requires all ipv4 nodes to communicate with ipv6 nodes during the migration period. It is also important that technology is in place to allow ipv6 nodes can communicate over the ipv4 internet to other networks. To meet the needs of the different network topologies that are spread throughout the internet, there are multiple paths for making this change.

The basic steps for an organization to follow for ipv6 migration;

Upgrade applications to support ipv6 addressing ,upgrading of applications can often be difficult and take many years to complete. Simply the cost in new licenses for a product that might work perfectly fine now, is enough to make corporations delay upgrades. if corporations are not interested in upgraded products, than there is little demand for software developers to produce new products.

Upgrade the DNS infrastructure to handle ipv6

Upgrade and implement an ipv6 capable routing infrastructure.

Upgrade hosts to ipv4 /ipv6 compatible nodes.

Upgrade the routing infrastructure to native ipv6 routing

Convert all nodes to ipv6 only

Dual stack

A dual stack technique is carried out with routers in place that handle both ipv4 and ipv6 protocols .with routers handling both protocols. It is possible for a network packet to have both ipv4 and ipv6 hosts. Supporting both protocols eliminates the concern that ipv4 hosts might be unable to communicate during early stages of a transition. A major drawback of using dual stack is that every dual stack host requires an ipv4 address. Even though dual stack is a fundamental method for making the transition to ipv6 , it is not useful as a long term solution.

A major advancement for using dual stack was the introduction of the dual stack transition mechanism or DSTM. DSTM is useful in common circumstances where few ipv4 addresses are available. In DSTM a host is given an ipv4 address on a temporary basis to less the burden on the available ipv4 address pool. DSTM also provide ipv4 applications to run over an ipv6 network.

Tunneling

Another method used to handle the migration is ipv6 over ipv4 tunneling. tunneling lakes an ipv6 packet and encapsulates it in an ipv4 packet to allow the ipv4 infrastructure to handle it. In its basics ,tunneling uses a logical link from source to destination. In the case of ipv6 ,tunneling allows for ipv6 hosts to communicate over ipv4 infrastructures. Tunneling ,as defined in RFC 2893 ,allows for three different configurations ; router to router, host to router, and host to host. The intra site automatic tunnel addressing protocol and 6to4 make tunneling possible.

Router to router tunneling is the connection of ipv4.ipv6 infrastructure to another ipv4/ipv6 infrastructure over an ipv4 infrastructure. An example of this scenario is a department or portion of the company that is using ipv6 and has their traffic tunneled through the company’s ipv4 infrastructure to arrive at the ipv6 internet.

Host to host tunneling is tunneling between two ipv4 and ipv6 nodes that both reside on the same ipv4 infrastructure. The resulting tunnel between the two nodes spans the entire path and acts as a single hop. This situation might be found as ipv6 is slowly implemented on a network packet where all hosts are not migrated at the same time. Thus the ipv4 and ipv6 hosts all need to communicate using the ipv4 infrastructure.

Host to router tunneling allows an ipv4 and ipv6 node to create an ipv6 over ipv4 tunnel to cross an ipv4 infrastructure to reach an ipv4 and ipv6 router . much like host to host tunneling ,the resulting tunnel act as a single hop. This can be seen in an environment where an ipv4 and ipv6 node is being tested in the marketing department and needs to cross the ipv4 infrastructure to communicate with nodes that are currently ipv6 in an ipv6 infrastructure.

Conclusion

Consumer upgrades are underway ,but will take a long period of time . consumer products will drive consumer upgrades. Mobile ip devices, home gaming systems and other consumer focused products will begin to incorporate ipv6 ,bringing it into the home. Mobile ip devices are already connecting to 802.11 hot spots that run ipv6.ISP upgrades to ipv6 will likely be consumer driven. As some ISP’s begin to upgrade their networks to ipv6, users will see further ipv6 integration in their homes.

Business upgrades to ipv6 will be primarily affected by return on investment. Return on investment for ipv6 is increased due to training costs and the actual cost of software and hardware upgrades. Ipv6 compatible applications are required for the initial stages of this migration within companies. As legacy equipment is replaced or other demands force upgrades , business will make these transition .corporations may be likely to move to ipv6 if other corporations realize reduced overhead following a migration to ipv6.if there is a very low RFC for ipv6, corporations are unlikely to migrate until there is a major business need, such as applications or operating systems that are require ipv6.

Ipv6 implementation and migration cannot and should not happen overnight. Major changes are required in all areas of industry to allow migration. Countries and companies both large and small, must make the move to ipv6 before overall migration of the internet backbones can happen. As organizations test and complete their migration to ipv6, we move closer to an ipv6 internet. Some estimates that ipv6 will not be fully implemented until 2030 or as late as 2040.while major steps are being made towards implementation of the new protocol completely ipv6 internet is many decades away.