Network Address Translators and IPv6 - Coursework Example

 IPv6: Background, design, and progress Table of Contents Introduction 1 The problems of IPv4 that may require IPv6 2 The design goals of IPv6 4 The current state of IPv6 (as up to date as possible) 8 The conversion process from IPv4 to IPv6 9 IPv6: Background, design, and progress Introduction The internet is growing rapidly, much faster than anticipated at its inception. As technology, society and economies progress, there is an escalating need for connectivity across various domains. This need for connectivity is no longer as simple as an exchange of text and pictures but has now evolved to a direct interaction for the end user, and will continue to grow rapidly as an extension of how people interact with each other and with the world around them. As a platform for this experience and communication, the current state of the internet is facing many issues and shortfalls as the technology and systems are rapidly falling behind in the attempt to support unforeseen demands. Events that have triggered this situation include demands such as mobile computing platforms, delivery of high definition video streams and perhaps even virtual reality scenarios. At the very basic level, the internet is all about exchange of information from one point to another. It all depends on the way this information transfer is managed. The system planned out for this many years ago worked well, and is still working. Although by now it is heavily burdened and inefficient for the current requirements. The core of this system is the Internet Protocol (IP) that allows data to stream from one point to another. The protocol in use at the moment for internet communication is Internet Protocol version 4 (IPv4). With increasing demand from users, the IPv4 protocol was seen as inadequate. Thus the need for an updated protocol that incorporates support for greater functionality, is easier to manage and faster in functionality. This new protocol has been in development for a number of years and is now being considered as the next step in providing a better internet experience from the infrastructure point of view. The following discussion enumerates the problems and limitations of IPv4, comparison of IPv4 and IPv6, the current state of IPv6 deployment and transitional strategies that will be needed for a smooth change over to IPv6. The problems of IPv4 that may require IPv6 The unforeseen exponential growth of the internet is fast becoming an issue due to the limited address space available in the IPv4 header. IPv4 supports 32 bit addresses. It has recently become a greater cause for concern as most available addresses have been allocated and a very small number are left that will be used up in the very near future. As the number of internet users increases exponentially worldwide, there is the impending possibility of address exhaustion. Network Address Translators (NAT) are one way in which addresses may be reused, but require additional resources to implement and manage. Security is fast becoming a major issue as the internet increases in scope and capability. In IPv4, security is implemented through IPsec, which is an optional field. This leads to uncertainty as any application requiring secure traffic cannot rely with certainty on the availability of this parameter. This has often forced the use of proprietary security implementations. IPv4 address configurations are managed through DHCP (Dynamic Host Configuration Protocol) this is a flexible scheme that works well, but does require a separate infrastructure and its management. Another aspect is that IPv4 was not built with multimedia applications in mind. Such applications require efficient and minimal delay in transport. Hence a new structure is required with more comprehensive support for such traffic. (Gai, 1998: pp. 207-8) Prioritized data packet delivery, required for multimedia, especially audio and video, at the moment depends on a specific interpretation of the Type Of Service (TOS) field in IPv4 protocol. This interpretation may not be supported by all network devices. Identification of the packet flow must be done using an upper layer protocol such as TCP or UDP, further adding a step and leading to inefficiency. With the recent introduction of mobile connectivity, a device may change physical location while requiring that it maintain its connection without an interruption in the flow of data. This means frequent change of address and physical connectivity. While there is a specification for IPv4 mobile connectivity, lack of infrastructure makes this unpredictable and inefficient (Das, 2008). The design goals of IPv6 The most urgent and needed change in IPv6 has been that of address space: an increase to 128 bits. This is in contrast to the previous specification of IPv4 which had 32 bit space allocation (Deering & Hinden, 1998). Using IPv6 will allow every end user to allocate a unique IP to any device accessing the internet. This is a much needed feature as we are close to exhausting the address space allocation in IPv4. Due to the inefficiencies and limitations of IPv4, the management of routing tables globally have become a complex and tedious process (Stockebrand, 2007:p. 5). With IPv6 providing a much better streamlined flow and a true hierarchical address space, the issues with routing tables will become easier to manage. Another goal for IPv6 is to facilitate configuration and management of networks. Where IPv4 requires DHCP for address acquisition, IPv6 protocol can operate in what is called a “stateless” configuration, where the address acquisition is automated (Thomson & Narten, 1998: pp. 1-3). DHCP has not been abandoned completely in IPv6 and is offered as DHCPv6 when required. IPv6 design also provides major improvement in network data flow speed. By optimising the header fields and overall size (Deering & Hinden, 1998: pp. 1-6), end to end transport of data is streamlined and made much more efficient. The re-engineering of the header also provides for much easier and flexible extensibility. This becomes particularly useful in quicker deployments. For example it is easier to add options when needs and requirements change. A major need addressed by IPv6 is that of multimedia and real-time applications which require high bandwidth and minimal delay in transfer of data. Currently these applications utilize IPv4, which has minimal support in this area and not all routers and hosts have provision for this option (Mun & Lee, 2005: p: 11). IPv6 was built with this in mind and has strong support in this regard. With Ipv6, multicast is a protocol requirement. Ipv6 also adds a new service called ‘anycast’. Similar to multicast, which sends data to a group of receivers, the anycast service allows for delivery to the closest available member of the group that can receive the data (Ross, 2010). This feature is particularly useful for fault tolerant implementations of networks. IPv6 also offers a major boost for creating virtual private networks (VPN). VPNs due to their nature require a strong security base. Normally, for network traffic, security is implemented using the IPsec service. This service is not incorporated directly in the IPv4 protocol thus making it difficult to manage. IPv6 however has this strong security services built-in (Gai, 1998: p. 153) thus making secure VPNs easier to implement. The protocol data unit (PDU) of IPv6 as compared to IPv4 The PDU for any protocol transferring data is the control information along with its attached data payload. Considering that the data is variable and user dependent, the main difference in IPv4 and IPv6 protocol data unit is mainly the control information encapsulated in the header. There are differences in most fields of the header but space does not permit listing all of them. The more significant or high impact changes are mentioned below. Compared to IPv4, the IPv6 header is much simpler. IPv6 datagrams use a structure that always includes a fixed 40-byte base header as compared to a minimum 20-byte header for IPv4 (which can go up to 60 bytes maximum). As already mentioned, though there are lesser fields in IPv6, the 40 byte length mainly accommodates the much larger source and destination addresses (see figures 1 and 2 below). Optionally, IPv6 includes one or more extension headers. This allows for improved faster processing of packets and protocol flexibility as the extension header are only used when needed. Some extension headers used by IPv6 are: “Hop-by-Hop Options header Destination Options header Routing header Fragment header Authentication header Encapsulating Security Payload header Destination Options header Upper-layer header” (Deering & Hinden, 1998) Figure 1: IPv4 header (Information Sciences Institute, 1981) Figure 2: IPv6 header (Deering & Hinden, 1998) In IPv6, five previous IPv4 header fields have been removed. These are IP “header length, identification, flags, fragment offset, and header checksum” (Kozierok, 2005: p. 406). The Ipv6 header fields are as follows: version (IP version 6), traffic class (replacing IPv4’s type of service field), flow label (a new field for Quality of Service (QoS) management), payload length (length of data following the fixed part of the Ipv6 header), next header (replacing IPv4’s protocol field), hop limit (number of hops, replacing IPv4’s time to live field), and source and destination addresses. IPv6 employs extension headers as a replacement for the options field in IPv4. These are optional headers that are inserted into the stream only if needed, hence they do not add to the base header length (Deering & Hinden, 1998). The current state of IPv6 (as up to date as possible) Figure 3: Percentage of IPv6 enabled networks (Emile, 2010) Figure 4: IPv4 Allocated addresses - Top 10 Economies (Huston, 2010) As can be clearly seen from the preceding graph and the table in figures 3 and 4, the adoption of IPv6 is rapidly on the rise. In early 2010, John Curran, the CEO of American Registry of Internet Numbers (ARIN) warned content providers to move to IPv6 by January 2010 or risk losing customers (Marsan, 2010a). The adoption of IPv6 has picked up in the last two to three years (see Figure 3). Major web powerhouses such as Google (Google) and Facebook (Marsan, 2010b) are already IPv6 compliant. Currently, most PC operating systems including Microsoft Windows support IPv6, thus the majority of end users are ready for IPv6 connectivity. The conversion process from IPv4 to IPv6 IPv4 which was developed in the late 1970’s allowed for an address range of about 4 billion. While it may be hard to imagine that this would not be enough, with the current state of the internet it is rapidly falling short of predicted demand in the very near future. In order to solve this issue and a number of others inherent in the IPv4 scheme, a better version was proposed and developed, called IPv6. The solution to current issues requires a transition from IPv4 to IPv6 globally with the goal of providing better end to end connectivity, easier management and lower costs. The conversion process from IPv4 to IPv6 does require significant effort as IPv6 is not backwards compatible with IPv4. Therefore there will be a significant change in the network infrastructure and systems needed to deploy IPv6. Since such wide scale and costly deployment is not possible simultaneously and systems need to be put in place to handle both IPv4 and IPv6 in parallel. This leads to planning strategies which maintain functionality and security without hampering the smooth flow of information. There is a transition strategy called the dual stack strategy where the devices comprising the network infrastructure are capable of handling both IPv4 and IPv6 (Cisco, 2010). This requires infrastructure that can operate with both systems separately and also should be able to handle a mix of both (Cisco, 2010). Currently most major network component vendors have already added support for IPv6. Figure 5: Example of a Dual Stack Network (Cannon, 2010) Currently even though about 90% of popular PC operating systems by now have built in support for IPv6 (Linux, Windows, Mac OS X), only 25% of users have their operating systems set to IPv6 settings by default. Many operating system installations will “require extra configuration” (OECD, 2010: p23). Lack of expertise in IPv6 may lead to implementation errors or vulnerabilities with possible exploitation of these vulnerabilities by others better versed in the intricacies of the IPv6 protocol. It is advisable for companies to experiment and gain familiarity on a closed local IPv6 implementation before deployment for mainstream use (Frankel, Graveman, Pearce, & Rooks, 2010: ES-2). However it happens, the transition phase from IPv4 to IPv6 will take many years. It is thus reassuring to know that the major internet infrastructure players are actively participating in this transition. References Cannon (2010, December). Potential Impacts on Communications from IPv4 Exhaustion & IPv6 Transition. Retrieved from http://www.fcc.gov/Daily_Releases/Daily_Business/2010/db1230/DOC-303870A1.pdf Cisco (2010). Dual Stack Network. Retrieved from http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6553/at_a_glance_c45-625859.pdf Das, K. (2008). A Beginner's Look into IPv6. Retrieved from http://www.ipv6.com/articles/general/IPv6-Beginners_Look.htm Deering, S., & Hinden, R. (1998, December). Internet Protocol, Version 6 (IPv6) Specification. Retrieved from http://www.ietf.org/rfc/rfc2460.txt Emile, A. (2010, November 12). Interesting Graph - Networks with IPv6 over Time. Retrieved from http://labs.ripe.net/Members/emileaben/interesting-graph-networks-with-ipv6-over-time Frankel, S., Graveman R., Pearce, J., & Rooks, M. (2010, December). Guidelines for the Secure Deployment of IPv6. Retrieved from http://csrc.nist.gov/publications/nistpubs/800-119/sp800-119.pdf Gai, S. (1998). Internetworking IPv6 with Cisco Routers. McGraw-Hill. Google (2011). Google over IPv6. Retrieved from http://www.google.com/intl/en/ipv6/ Huston, G. (2010, January 10). Addressing 2010. Retrieved from http://www.circleid.com/posts/addressing_2010/ Information Sciences Institute (1981, September). DARPA Internet Program Protocol Specification. Retrieved from http://www.ietf.org/rfc/rfc791.txt Kozierok, C. M. (2005). The TCP/IP Guide. San Francisco: No Starch Press. Marsan, C.D. (2010a). Web sites must support IPv6 by 2010, expert warns. Network World. Retrieved from http://www.networkworld.com/news/2010/012110-ipv6-warning.html Marsan, C.D. (2010b). Facebook adds IPv6 support. Network World. Retrieved from http://www.networkworld.com/news/2010/061110-facebook-ipv6.html Mun, Y., & Lee, H.K. (2005). Understanding IPv6. Korea: Springer. OECD (2010, April). Internet Addressing: Measuring Deployment of IPv6. Retrieved from http://www.oecd.org/dataoecd/48/51/44953210.pdf Ross, C. (2010). IPV6 - What are Unicast, Multicast, and Anycast Addresses? Retrieved from http://adminkernel.com/cisco-systems/ipv6-what-are-unicast-multicast-and-anycast-addresses Stockebrand, B. (2007). IPv6 in practice: a Unixer's guide to the next generation Internet. New York: Springer. Thomson, S., & Narten, T. (1998, December). IPv6 Stateless Address Autoconfiguration. Retrieved from http://www.ietf.org/rfc/rfc2462.txt Read More