IPv6 The Big Move: Transition and Coexistent Frenil V. Dand Touro College 10
IPv6 The Big Move: Transition and Coexistent 2 Table of ContentIntroduction………………………………………………………………………… 2Advantages of IPv6 over IPv4……………………………………………………....4How does IPv6 work?............................................................................................... 4IPv6 Global Unicast Address………………………………………………………. 7IPv6 Multicast and Anycast Addressing…………………………………………… 9IPv6 Headers……………………………………………………………………….. 10IPv6 Address Autoconfiguration and Renumbering……………………………….. 13IPv4-IPv6 Transition and Coexistence…………………………………………….. 15Conclusion…………………………………………………………………………. 20Appendix 1…………………………………………………………………………. 22Appendix 2…………………………………………………………………………. 24
IPv6 The Big Move: Transition and Coexistent 3 AbstractThis paper talks about the move from current Internet Protocol (IPv4) to next generation ofInternet Protocol, which is refer to as the next-generation IP (IPng) or IP version 6 (IPv6). Itlooks at the history of IP and why the move is necessary. It talks about advantages of IPv6 overIPv4 and how IPv6 works and looks, since it’s completely re-designed. We look at the divisionof the address space and headers. Then we look at how IPv6 willcoexist with IPv4 over a longperiod of time. We look at some the technologies IPv6 and IPv4 networks will have to use inorder to talk to each other.There are number solution currently available ranging from off-the-shelf application to 3rd party vendor. Then there are other transition mechanisms which are morecomplex and involved that require much more work and new hardware/software implementationon the networks; before IPv4 traffic can talk to IPv6 or IPv6 can talk to IPv4. Also the operatingsystem like Windows 7 and Vista are IPv6 ready. We also look at some of the technologies thatwill help corporations with move, since most of the enterprises are behind NAT. This move ishappening worldwide and some of the country in Asia-Pac region are much more ahead thenU.S, although Federal Agencies have already made the move to IPv6.
IPv6 The Big Move: Transition and Coexistent 4Introduction:The next-generation Internet Protocol (IPng) or Internet Protocol version 6 (IPv6) as it’s knownformally in tech world is successor to current Internet Protocol (IPv4). The rate at which theInternet is growing it’s running out of IP address. There is a very cool counter athttp://www.ipv6forum.com/ and its counting down reaming IPv4 address. According to site X-day is May 30th 2011. Given the current rate at which IPv4 address are been take, its calculatedthat IPv4 address will completely run out in about 12 months plus or minus few weeks, that’ssometime in third quarter of 2011(Santo, 2010).Let’s talk bit of history, because those to forget the history are doom to repeat it. And we knowthat’s not case with IPv6, because IPv6 addresses are not running out any time soon. It all beganin the 60’s when ARPANET (Advance Research Projects Agency Network) was created; it wasdesign with Network Control Protocol (NCP). NCP made different types of host to connect onthe same network and talk to each other, but NCP had its limitations. So they stared the work onsomething new and better and the engineers split the massive NCP in two as we know it todayTCP and IP. An Internet Protocol (IP) that allows data to be routed between the differentnetwork and a Transport Control Protocol (TCP) take the data (Beijnum, 2007).TCP/IP as also its own limitations but unlike NCP it was served Internet and the tech world verywell since its birth in 80’s and it is doing until this day. But limitations on IP part of TCP/IP willmake further growth of the Internet come to halt, and impossible for new technologies and nextgeneration of eBay’s and Google’s to emerge. Not only IP is limited by its 32 bit address size butits QoS (Quality of Service) and security as well. With 32 bits, its possible to express4,294,967,296 different values. Over half a billion of those are unusable as addresses for variousreasons, giving us a total of 3.7 billion possible addresses, inadequate for giving even oneaddress to every living person, much less to new generation of IP cars, phones, PDA’s, T.V’sand
IPv6 The Big Move: Transition and Coexistent 5refrigerators; while IPv6 supports about 340 undecillion (1036) addresses.We know IPv6 is goingto give very very very large amount of address space since it is based on 128bits. This number isbeyond enormous 340,282,366,920,938,463,463,374,607,431,768,211,456. Beijnum very nicelyput this number perspective: there are currently 130 million people born each year. If thisnumber of births remains the same until the sun goes dark in 5 billion years, and all of thesepeople live to be 72 years old, they can all have 53 times the address space of the IPv4 Internetfor every second of their lives.(Beijnum, 2007).Work on IPv6 has be going on since the early 90’s and it was first to be implemented in Linuxand IBM’s AIX (Langley, 2007). It has been adopted by the Internet Engineering Task Force(IETF) since then. The IETF is the standards body responsible for IPv6 and IPv4. Move to IPv6has been slowed by Network Address Translation (NAT), which could whole another paper.Basically with NAT you only need one public IP address and all the hosts behind a NAT devicewill be given one of the private IP blocks e.g. 10.0.0.0, 172.16.0.0 or 192.168.0.0. These addressblock have been set aside for private use in RFC 1918. But NAT does not solve the problem butonly make things more complex with peer-to-peer application like the multi-user games, VoIPand only prolongs address issue (Beijnum, 2007). Some of the leading Web content providerslike Google, Yahoo, Netflix, and Microsoft are already in talks about creating a shared DNSWhitelist of customers who can access their Web sites using IPv6 and would use this list toprovide the content to these Whitlisted IP’s via IPv6 rather than through IPv4. Google has saidthat the DNS Whitelist for IPv6 was the easiest way it could provide IPv6 services withoutblocking customers with broken IPv6 links (Marsan, Google, Microsoft, Netflix in talks to createshared list of IPv6 users; Open source whitelist would aid transition to next-gen Internet service,proponents say, 2010).
IPv6 The Big Move: Transition and Coexistent 6Advantages of IPv6 over IPv4:Let’s talk about some of the advantages of IPv6 over IPv4. We know one of the biggestadvantages is trillions times more address than IPv4, but there are others as well. 1. Larger address space. 2. Simpler and leaner headers by removing six unnecessary fields and adding one new field. This will provide for more efficient routing. 3. It will much easier to configure IPv6 because it supports both stateful and stateless address configurations. It uses neighbor discovery to find other IPv6 systems and work with or without DHCP server. 4. Much more secure, since the IPSec is mandatory. 5. Better Quality of Service, this is part of the new header field. These fields will define how the traffic is identified and routed. 6. Better real-time performance by packet prioritization this will improve the response time of real-time applications. 7. IPv6 also has improved multicast support, unlike IPv4 it does not support broadcast. IPv6 has much broader range for multicast address which will perform all the functions that required broadcasts. Multicast is a very basic and essential feature of IPv6 (3Com, 2004).See Table 1: Comparison between IPv4 and IPv6 (3Com, 2004).How does IPv6 Work?This is a great analogy by Allied Telesis, when there is a shortage of telephone number in largercity; additional digits are added to the front of the telephone numbers to increase the amount ofavailable numbers. In the same way, IP addresses shortage is solved in IPv6 by adding additionalbytes to the IP address. But it is easier said than done and bit more complex, so the change is not
IPv6 The Big Move: Transition and Coexistent 7going to be overnight like in the case of adding the telephone number. There for IPv4 and IPv6are going to have to play nice with each other to coexist over a transition period (Allied Telesis,2007).IPv6 AddressingIPv6 addresses not only look much different than IPv4 address, but they are built different andhave hierarchical addressing. IPv6 increases the IP address space from 32 bits to 128 bits (seefigure 1). The new 128-bit IPv6 addresses are written in the form of 8-16 bit hex componentsseparated by colons (e.g. X:X:X:X:X:X:X:X) unlike the IPv4 address X.X.X.X. Let’s take a lookan actual IPv6 address and how it can be compressed. Like we said IPv6 addresses are written inhexadecimal notation, rather than familiar dotted decimal notation of IPv4, as shown in thefollowing example:2001:0DB8:C003:0001:0000:0000:0000:F00DCan be represented in shorter format by removing leading zeros2001:DB8:C003:1:0:0:0:F00D Further reduction by removing consecutive fields of zeros using the double-colon :: option Note the double-colon can be used only once, because multiple occurrences would lead to ambiguity (e.g. address 2001:0:0:FFD3:0:0:0:57ab, if written as 2001::FFD3::57ab, could represent 2001:0:0:0:0:FFD3:0:57ab/ 2001:0:0:0:FFD3:0:0:57ab/ 2001:0:0:FFD3:0:0:0:57ab/ and 2001:0:FFD3:0:0:0:0:57ab.2001:DB8:C003:1::F00D(Cisco Systems, 2006)IPv6 addresses are organized in hierarchical manner. Let’s use Allied Telesis telephone analogyto understand this better. In a telephone hierarchical structure is obtain through use of area code,
IPv6 The Big Move: Transition and Coexistent 8city code, and country code, allowing aggregation by using shorter telephone numbers closer tohome. But as you are dialing far away you will have to use extra number or code to reach faraway. In IPv6 aggregation is obtained by providing an address prefix and the organization ofaddresses into two levels they called public topology and interface identifier. Public topology isfor providers of public Internet services and the interface identifier is for specific node on a link.Hierarchical routing allows for smaller routing tables and more efficient address allocation.Faster routes lookup and reduced latency are direct result of this. The general format IPv6address will look like this (see figure 2)(Allied Telesis, 2007).Basically there are three address types which are supported by IPv6:Unicast AddressesOne-to-one this type of communication is between a single host and a single receiver. Packetssent to a unicast address are delivered to the node identified by that address.Multicast AddressesOne-to-many this has replaced broadcast address type from IPv4. These addresses couldrepresent various groups of IP devices. A message sent to multicast address goes to all the nodesin that group. In IPv6 multicasting is required address type. Has much better feature and manymore addresses.Anycast AddressesOne-to-nearest this is allocated from unicast, is used when a message must be sent to any node inthe group, but does not need to go to all, usually the node that is easiest to reach (Das, 2008).Special address typesBesides the three address types we just discussed, IPv6 has several other types of addresses. Thetwo most important special purpose address types are:
IPv6 The Big Move: Transition and Coexistent 9Link localThese addresses are used to communicate over one physical or logical network or subnetwork.These addresses are extensively used for IPv6’s internal network and start with FE80.They areautomatically configured on a IPv6 node by using prefix FE80::/10. Link-local addresses are alsoused in the neighbor discovery protocol, even in the absence of all other unicast addresses(Kozierok, 2005).Site localThis is the IPv6 equivalent of the RFC 1918 private address space in IPv4. But IETF found asituation it did not like where if different organizations use the same address space, so theycreated a “unique site local” addresses where organizations takes a randomly selected block outof IPv6 address space starting with FD (Beijnum, 2007).IPv6 Global Unicast Address:A very large number of IPv6 address space is dedicated to unicast addressing because it will beused for the vast majority of the Internet traffic under IPv6. One-eighth of all the IPv6 addresswill be unicast addresses which start with 001 in the first three bits of the address. So whathappens to the remaining 125 bits and how do we use them.When Internet was first created using IPv4 it was very small and easy to manage, anyone thatwanted a presence on the web when to the Internet Assigned Numbers Authority and got an IP.As the Internet got bigger and bigger it got harder to manage and IANA model was not working.So the big ISP got large blocks of IP from the IANA and sold them or leased them to thecustomers. Learning from this experience the designers of IPv6 have incorporated overalltopology of the Internet in designing unicast address with tremendous advantages some of themare as follows:
IPv6 The Big Move: Transition and Coexistent 10 Easier allocation of address block at any levels of the Internet topological hierarchy. ISP’s have greater flexibility to subdivide address blocks for customers End-used organizations have more flexibility to subdivide their address blocks to match internal networks. IP addresses will have more meaning to them. It won’t be just string of HEX number with no structure. You would be able to tell certain things about it just by looking at the number (Kozierok, 2005).Division of IPv6 Address Space128 bits of the unicast address space is divided into three sections: Site prefix Subnet ID Interface IDThese three components are identified by the position of the bits within the address. The firstthree fields in an IPv6 address make up the site prefix (in red). The next field represents thesubnet ID (in blue). And the last four fields are used for the interface ID (in green).2001:0DB8:C003:0001:0000:0000:0000:F00DThe first 48 bits of site prefix are equivalent to network number in IPv4, this is used for routing,and the first three bits are always “001” to indicate a unicast address. The next 16 bits are subnetID, a number that identifies a subnet within the site. Gives us 64 bits remaining for the interfaceID which is a unique identifier for a particular interface this could be a host or any other device.This will be unique within a specific prefix and subnet (Kozierok, 2005).IPv6 Multicast and Anycast Addressing:
IPv6 The Big Move: Transition and Coexistent 11Since Broadcast as an address type has been eliminated from IPv6 and Unicast addresses are stillthe choice for the vast majority of communications as it was in IPv4. But the “bulk” addressingmethods are different in IPv6. Hence one of the major changes to general addressing model inIPv6 was a change to the basic types of addresses, support for Multicast addressing has beenexpanded and a required part of IPv6, and a new address type called Anycast (Kozierok, 2005).Multicast AddressesA multicast address identifies multiple interfaces it is used to allow a one device to send packetsto group of devices. All multicast addresses start with prefix format of “FF” in Hex or 1111 1111in binary. The key here is the second octet or the next four bits it defines the lifetime of theaddress. They are called the Flags bit 0 = permanent and 1 = temporary. The next four bits afterthat defines the scope of the address. There are possible of 16 different values from 0 to 15, thesevalues make it possible for multicast addresses to be created that are global to the entire Internetor restricted smaller environment or to a specific organization. That leaves us with remain 112bits which are used for group ID, it defines a specific group within each scope level (Kozierok,2005).Anycast AddressesThis is the new and unique address type that is new to IPv6. You can think of anycast address asa mix between unicast and multicast addresses. Unicast sends packet to only one address andmulticast send packet to every member of the group, but anycast sends the packet to any onemember of the group choosing the closest member on its route. Router have to be configured torespond to anycast packets will do so when a packet comes in for the anycast address (Kozierok,2005).IPv6 Headers:
IPv6 The Big Move: Transition and Coexistent 12The simplified header allows for easier and less complicated processing of IP packets. Theheader fields are as follows: Source Address, Destination Address, Version, Class, Flow label,Payload Length, Next Header, and Hop Limit. There are few changes to the format and fields(see figure 3), gives a high-level view of the basic comparison between the IPv4 and IPv6. IPv6has better Quality of Service (QoS) or content prioritization over IPv4 by using headercompression and optional header extensions(Allied Telesis, 2007).Source address (128 bits) The 128-bit source address field contains the IPv6 address of theoriginating node of the packet. It is the address of the originator of the IPv6 packet.Destination address (128 bits) The 128-bit contains the destination address of the recipientnode of the IPv6 packet. It is the address of the intended recipient of the IPv6 packet.Version/IP version (4-bits) The 4-bit version field contains the number 6. It indicates theversion of the IPv6 protocol. This field is the same size as the IPv4 version field that contains thenumber 4.Packet priority/Traffic class (8 bits) The 8-bit Traffic Class field replaced the Type of Service(TOS) field in the IPv4 header. IPv6 header can assume different values to enable the sourcenode to differentiate between the packets generated by it by associating different deliverypriorities to them. This field is used by the originating node and the routers to identify the datapackets that belong to the same traffic class and distinguish between packets with differentpriorities.Flow Label/QoS management (20 bits) The 20-bit flow label field in the IPv6 header can beused by a source to label a set of packets belonging to the same flow. This field is new to IPv6.This will improve quality of real-time service, because all packets belonging to the same flowmust be sent with the same source address, destination address, and flow label. Router saves a
IPv6 The Big Move: Transition and Coexistent 13cache of handling requirement for a particular flow label is known as the state information.When packets arrive at a router it can be efficiently routed to the destination since theinformation is already cached and the router does not have to examine the rest of the header foreach packet in same flow.Payload length in bytes(16 bits) The 16-bit payload length field replaced the Total Length fieldfrom the IPv4 header. But unlike IPv4 header it does not measure the length of the whole packet,it only contains the number of bytes of the payload. It puts an upper limit on the maximumpacket payload to 64 kilobytes. In case a higher packet payload is required, a Jumbo payloadextension header is provided in the IPv6 protocol.Next Header (8 bits) The 8-bit Next Header field replaced the Protocol field and serves twopurposes. Itidentifies the type of header immediately following the IPv6 header and located atthe beginning of the data field (payload) of the IPv6 packet. This field usually specifies thetransport layer protocol used by a packets payload. When a packet only has main header and noextension headers, it is used as the old IPv4 Protocol field and has the same values.Hop Limit (8 bits)The 8-bit Hop Limit field replaced Time To Live (TTL) field in the IPv4header. If the Hop Limit field is decremented to zero, the packet is discarded. The main functionof this field is to identify and to discard packets that are stuck in an indefinite loop due to anyrouting information errors (Das, 2008).IPv6 Extension HeadersThe IPv4 header includes all options. Therefore, each intermediate router must check for theirexistence and process them when present. This can cause performance degradation in theforwarding of IPv4 packets. With IPv6, delivery and forwarding options are moved to extensionheaders. The only extension header that must be processed at each intermediate router is the
IPv6 The Big Move: Transition and Coexistent 14Hop-by-Hop Options extension header. This increases IPv6 header processing speed andimproves forwarding process performance.RFC 2460 defines the following IPv6 extension headers that must be supported by all IPv6 nodes(Cisco Systems, 2006): Hop-by-Hop Options header Destination Options header Routing header Fragment header Authentication header Encapsulating Security Payload headerIn a typical IPv6 packet, no extension headers are present. If special handling is required byeither the intermediate routers or the destination, one or more extension headers are added by thesending host. Most IPv6 extension headers are not examined or processed by any router along apacket’s routing path until the packet gets to the final destination. This results in a majorimprovement in router performance for packets containing extensions. Each extension headermust fall on a 64-bit (8-byte) boundary. Extension headers of variable size contain a HeaderExtension Length field and must use padding as needed to ensure that their size is a multiple of 8bytes(Hinden, 1996).IPv6 Address Autoconfiguration and Renumbering:A highly useful aspect of IPv6 is its ability to automatically configure itself without the use of astateful configuration protocol, such as Dynamic Host Configuration Protocol for IPv6(DHCPv6). By default, an IPv6 host can configure a link-local address for each interface. Byusing router discovery, a host can also determine the addresses of routers, additional addresses,
IPv6 The Big Move: Transition and Coexistent 15and other configuration parameters. Included in the Router Advertisement message is anindication of whether a stateful address configuration protocol should be used.Address autoconfiguration can only be performed on multicast-capable interfaces. Addressautoconfiguration is described in RFC 2462, "IPv6 Stateless Address Autoconfiguration."(Kozierok, 2005)The following is a summary of the steps a device takes when using stateless autoconfiguration: 1. Link-Local Address Generation The device generates a link-local address. You’ll recall that this is one of the two types of local-use IPv6 addresses. Linklocal addresses have 1111 1110 10 for the first 10 bits. The generated address uses those 10 bits, followed by 54 zeros and then the 64-bit interface ID. Typically, this will be derived from the data link layer (MAC) address as explained in the "IPv6 Interface Identifiers and Physical Address Mapping" section earlier in this chapter, or it may be a "token" generated in some other manner. 2. Link-Local Address Uniqueness Test The node tests to ensure that the address it generated isn’t already in use on the local network. (This is very unlikely to be an issue if the link-local address came from a MAC address; it is more likely that the address is already in use if it was based on a generated token.) It sends a Neighbor Solicitation message using the ND protocol. In response, it listens for a Neighbor Advertisement, which indicates that another device is already using its link-local address. If so, either a new address must be generated or autoconfiguration fails, and another method must be employed. 3. Link-Local Address Assignment Assuming the uniqueness test passes, the device assigns the link-local address to its IP interface. This address can be used for
IPv6 The Big Move: Transition and Coexistent 16 communication on the local network, but not on the wider Internet (since link-local addresses are not routed). 4. Router Contact The node next attempts to contact a local router for more information on continuing the configuration. This is done either by listening for Router Advertisement messages sent periodically by routers or by sending a specific Router Solicitation message to ask a router for information on what to do next. 5. Router Direction The router provides direction to the node about how to proceed with the autoconfiguration. It may tell the node that on this network stateful autoconfiguration is in use, and it may give it the address of a DHCP server to use. Alternatively, it will tell the host how to determine its global Internet address. 6. Global Address Configuration Assuming that stateless autoconfiguration is in use on the network, the host will configure itself with its globally unique Internet address. This address is generally formed from a network prefix provided to the host by the router. The prefix is combined with the device’s identifier, as generated in step 1.This method has numerous advantages over both manual and serverbased configuration. It isparticularly helpful in supporting the mobility of IP devices, because they can move to newnetworks and get a valid address without any knowledge of local servers or network prefixes. Atthe same time, it still allows for the management of IP addresses using the (IPv6-compatible)version of DHCP, if that is desired. Routers on the local network will typically tell hosts whichtype of autoconfiguration is supported using special flags in Internet Control Message Protocolversion 6 (ICMPv6) Router Advertisement messages (Kozierok, 2005).IPv6 Transition & Coexistence:As of today if you are on the Internet, you are using only IPv4 which would be the majority ofthe population. But there are parts of Internet that are also running on IPv6. And if you are only
IPv6 The Big Move: Transition and Coexistent 17running IPv4 you will not be able to get to parts of Internet running IPv6, which is increasing as Iam writing this paper. Unfortunately IPv4 and IPv6 are incompatible protocols. As a user if youwant to access all part of the Internet running IPv4 and IPv6 you will require some kind oftechnology that will allow you visit the IPv6 world. IPv6 will have to coexist with IPv4 until theentire migration is completed. This is no simple task and one that could be year inprogress(Punithavathani & Sankaranarayanan, 2009). The degree of difficulty is huge especiallyfor large and complex networks. Some IT professionals have described it as to changing theengine on a moving airplane (Fischman & Grassi, 2008).There are various transition technologies available to help achieve seamless coexistence duringthe transition period. IETF has also created the Ngtrans Group to facilitate smooth transition.There are three major categories for transition technologies (Punithavathani &Sankaranarayanan, 2009): Dual stack Tunneling TranslationDual-StackThis is one of the main transition/coexistence techniques used, as the name says it all “Dual-stack” this technique includes two protocol stacks that run in parallel (see figure 4). It allowsnetwork nodes to communicate either via IPv4 or IPv6 and can be implemented on both endsystems such as workstation or server and network nodes such as routers and switches. There isno direct communication between IPv4 and IPv6. On the workstations and servers it enables
IPv6 The Big Move: Transition and Coexistent 18both IPv4 and IPv6 applications to operate at the same time and on the network side it transportsboth the IPv4 and IPv6 packets. A major challenge with dual-stack is that all network resourcesneed to have plenty of processing power to allow two different IP stacks at same time. And itwill also require dual management of the network (Fischman & Grassi, 2008).IPv4 applications use the IPv4 stack, and IPv6 applications use the IPv6 stack. Version filed ofthe IP header is used to make flow decisions for receiving and on the destination address typefor sending packets. DNS lookups are used to get address types and the appropriate stack isselected based upon types of DNS records returned. Great thing about dual-stack mechanism isthat many off-the-shelf operating systems already have dual-stack IP protocol built in. Thereforethis is one of the most widely used transition method used currently(Miller, 1997).TunnelingAnother transitioning technology is the use of tunnels. This technology encapsulates oneprotocol type within another protocol. If you look at it from the transitioning standpointtunneling allows incompatible networks to be linked, which you are not able to do with standalone dual-stack. You can encapsulate IPv6 packet inside an IPv4 and transport it over IPv4network. But tunneling does require running dual-stack at each end of the tunnel. Three maintunneling techniques are(Punithavathani & Sankaranarayanan, 2009): IPv6 over IPv4 IPv6 to IPv4 automatic tunneling Tunnel BrokerThe tunneling process dose involves three distinct steps (Miller, 1997): Encapsulation Decapsulation
IPv6 The Big Move: Transition and Coexistent 19 Tunnel managementStarting at the encapsulating node, or the tunnel entry point an IPv6 packet is placed inside thedata field of an IPv4 packet. So now the packet contains both an IPv4 header and an IPv6 headerwith all the upper layer information such as the TCP header and application data. Node that isdoing the encapsulation also manages configuration information regarding the tunnel or tunnelsthat are established. The IPv4 header is read by the router which sends the packet across the IPv4network to the decapsulating node or the tunnel endpoint. Over there the IPv4 header isexamined and then discarded leaving us with IPv6 header plus data that is then delivered to theIPv6 host (Miller, 1997).IPv6 over IPv4The IPv6 over IPv4 mechanism embeds an IPv4 address in an IPv6 address link layer identifierpart, which is the first octet of the address and defines Neighbor Discovery over IPv4 usingorganization-local multicast. IPv6 over IPv4 is a configured tunneling in which the networkadministrator will be involved in defining the endpoint configuration. Configured tunneling andautomatic tunneling are two techniques use by IPv6 node to see the end of the tunnel. A tunnelend point address is different from the final destination endpoint. Tunnel endpoint is usually arouter and final destination is an IPv6 node(Punithavathani & Sankaranarayanan, 2009).IPv6 toIPv4 Automatic TunnelingAutomatic tunneling is almost as same as configured tunneling, except (and the name says it all)here tunnel endpoint configuration does not require direct management or an administrator.Address has an IPv4 address embedded in the last 32 bits of the IPv6 address. The embeddedIPv4 address can be easily removed and the whole IPv6 packet can be delivered over the IPv4network, encapsulated in an IPv4 packet. There is no need for configured tunnel to send packet
IPv6 The Big Move: Transition and Coexistent 20among 6to4 and it can be implemented on border routers without major router reconfiguration.This is also called 6to4 and is the method of choice for user or network that wants to connect tothe IPv6 world of the Internet, but get there using IPv4 road. These users and network can alsotalk to other users and network that are travelling in same 6to4 bus (Punithavathani &Sankaranarayanan, 2009).TeredoThis is an extension of basic 6to4 tunneling that provides IPv6 connectivity to devices behindNAT. Teredo adds encapsulation over UDP putting IPv6 packets inside IPv4 packets and uses aNAT traversal across IPv4 based NAT devices. The name “Teredo” is part of the Latin name fora little worm that bores holes through wooden ship hulls (Hughes, 2010). Microsoft is one of thesupporters of Teredo and ships Vista and Windows 7 with Teredo enabled by default (Marsan,IPv6 Tunnel Basics, 2010).Companies like Hurricane Electric and Microsoft have made possible for publically availableTeredo relay service that allows any node with Teredo running to access the IPv6 Internet. Thishas improved the use of IPv6 Internet for an average user since the new Windows node arepreconfigured to use these Teredo relay services, giving this technology a great deal of boost(Hughes, 2010).Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)ISATAP is a transition technology which encapsulates and transmits IPv6 packets over IPv4networks. It is similar to 6over4; it provides automatic encapsulation by using a virtual IPv6overlay on top of an IPv4 network (Hughes, 2010). It is mostly targeted use for IPv6 roll out inenterprise network since it operates in dual-stack environment. ISATAP was enhanced to allow
IPv6 The Big Move: Transition and Coexistent 21for automatic IPv4-in-IPv4 encapsulation, this is a key component for the co-existence of IPv4and IPv6 in corporate networks (Marsan, IPv6 Tunnel Basics, 2010).IPv6 Tunnel BrokerBasically tunnel broker are third party service or vendors that provide automatic configurationservice for IPv6 over IPv4/6to4 tunnels to the users that are connected to IPv4. The users wouldstill require IPv4 connectivity to the service provider. The service works asfollows(Punithavathani & Sankaranarayanan, 2009): 1. The user contacts and registers with the Tunnel Broker. 2. The user provides configuration information such as IP address, OS, IPv6 support software and authenticates. 3. Tunnel Broker configures the network side end-point, the DNS server and the user terminal. 4. The tunnel is active and the user is connected to IPv6 networks.IPv4/IPv6 TranslationAccording to the IETF, translation was once considered tool of last resort. Translation schemesare becoming increasingly popular as the move IPv6 is picking up speed. The basic purpose oftranslation is to translate IP packet. But not simple as it sound, these schemes are highlycomplex.Translation can occur at any one of the several layers in the protocol stack, includingthe network, transport, and application layers. There are several translation technologies basedon Stateless IP/ICMP Translation algorithm and Network address Translation-ProtocolTranslation. This technology is used when there is only one IPv6 host is trying to communicatewith IPv4 host. This remains the only option of IPv6 transition that permits network node toentirely remove IPv4 addresses. Single-stack approach is a crucial part of translation technology,
IPv6 The Big Move: Transition and Coexistent 22which reduces the need for routing hardware, therefore reducing the need for extra IT resourcesto manage the network(Tantayakul, Kamolphiwong, & Angchuan, 2008).6rdIt’s short for IPv6 Rapid Deployment on IPv4 Infrastructure. This is another method ofencapsulating IPv6 packets for transmission over IPv4 backbone network. 6rd is big move indeploying IPv6 to residential consumer. It was used by French ISP called Free to roll over 1.5million residential customers to IPv6 in 2007 (Marsan, IPv6 Tunnel Basics, 2010). It is anextension of 6to4 tunneling that allows ISP to designate a relay as opposed to having a randomrelay chosen automatically, makes it easier to deploy IPv6 (Santo, 2010).This method requires home gateways/routers that can support 6rd and can do the encapsulationof IPv6 packets inside IPv4 and forward them across the backbone and sends it over to the ISP tohandle the tunneled IPv6 traffic. ISP provider Comcast is testing 6rd as one of the transitionmechanismas a part of its ongoing public trial of IPv6 (Marsan, IPv6 Tunnel Basics, 2010).Conclusion:Transitioning from IPv4 to IPv6 is not going to be an overnight, but one that’s going take manyyears to come. Interoperability is going to be one of the key factors. Therefore coexistence andbeing able to communicate between the two protocols will make the way for smooth transition(Fischman & Grassi, 2008).Internet Protocol version 6 or IPv6 an improved version of the current and most widely usedInternet Protocol, IPv4 will be no longer be a option or nice to have, it will be a necessity. Asintelligent appliances and IP cars will become new trend. In addition to creating more addressesso that more people and devices can connect to the Internet, IPv6 provides some exciting
IPv6 The Big Move: Transition and Coexistent 23enhancements like QoS and Security over IPv4(Tantayakul, Kamolphiwong, & Angchuan,2008).Japan, China and other countries Asia-Pacific region are already deploying and using IPv6. The2008 Beijing Olympics experienced the widest ever use of broadband and mobility servicessupported on IPv6 capability. IPv6 is already widely deployed in Japan. IPv6 was trialed as away of monitoring traffic by installing detectors in cars. Quickly seeing the potential of thistechnology, one Tokyo taxi company uses IPv6 technology to keep its customers dry. When itrains on one of their taxis and the windshield wipers are turned on, detectors on the wipers send amessage to the company’s headquarters. From this message, the company can locate the taxi anddispatch more taxis to that area in anticipation of more people wanting to stay dry and take cab totheir destination (Das, 2008).As of 2008 Federal Government and The Defense Department (DOD) has already completedtesting and transition phase for IPv6. IPv6 is real and it’s here now. Imagine give IP address toevery electronic or electrical device and allowing for direct communications between them,leading the way for new applications and technology. I truly believe IPv6 will take internet andthe world of communications to the next level.
IPv6 The Big Move: Transition and Coexistent 24Appendix 1: Table and FiguresFeature IPv4 IPv6Address Bits 32 128Configuration DHCP Auto/DHCPv6QoS DiffServ/IntServ DiffServ/IntServSecurity IPSec (optional) IPSec (mandatory)Multicast IGMP/PIM/MBGP MLD/PIM/MBGP (Scope ID) Table 1: Comparison between IPv4 and IPv6 Figure 1: IPv4 vs. IPv6 bits Figure 2: The general format for IPv6 addresses
IPv6 The Big Move: Transition and Coexistent 25 Figure3: IPv4 Header vs. IPv6 Header Figure 4: Dual Stack approach
IPv6 The Big Move: Transition and Coexistent 26Appendix 2:Works Cited3Com. (2004). IPv6 Technology Brief. Marlborough: 3Com.Allied Telesis. (2007). IPv6 White Paper. Bothell: Allied Telesis.Beijnum, I. v. (2007, March 7). Everything you need to know about IPv6. Retrieved June 2010, from arstechnica: http://arstechnica.com/hardware/news/2007/03/IPv6.ars/2Cisco Systems. (2006). IPv6 Concepts: Cisco Networks. Retrieved June 2010, from Cisco:http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6553/prod_presentation0900aecd80311dff.pdfDas, K. (2008). IPv6 Addressing: IPv6.com. Retrieved July 25, 2010, from IPv6.com:http://www.ipv6.com/articles/general/IPv6-Addressing.htmFischman, R. W., & Grassi, S. (2008, Nov 6). How to choose the right strategy for your IPv6 Migration.eWeek .Hinden, R. (1996). IP next generation overview. Communications of the ACM , 61-72.Hughes, L. E. (2010). The Second Internet: Reinventing Computer Networking with IPv6. In L. E. Hughes,The Second Internet: Reinventing Computer Networking with IPv6 (pp. 169-206). Cebu: InfoWeapons.Kozierok, C. M. (2005, September 20). IPv6 Global Unicast Address Format. Retrieved July 24, 2010, fromThe TCP/IP Guide: http://www.tcpipguide.com/free/t_IPv6GlobalUnicastAddressFormat.htmLangley, N. (2007, October 9). Transition skills in deamand as move to support IPv6 gains momentum.Computer Weekly , p. 52.Marsan, C. D. (2010, June 28). Google, Microsoft, Netflix in talks to create shared list of IPv6 users; Opensource whitelist would aid transition to next-gen Internet service, proponents say. Network Wolrd .Marsan, C. D. (2010, May 10). IPv6 Tunnel Basics. Network World , pp. 24-24.Miller, M. (1997, January 20). Making the Move. Network World , pp. 37-39.Punithavathani, S. D., & Sankaranarayanan, K. (2009). IPv4/IPv6 Transition Mechanisms. EuropeanJournal of Scientific Research , 110-124.Santo, B. (2010, May). Start reconfiguring your netowrk for IPv6. CED, 36 (4), pp. 48-49.Tantayakul, K., Kamolphiwong, S., & Angchuan, T. (2008). IPv6 @ Home. International Conference OnMobile Technology, Applications, And Systems . Yilan, Taiwan: ACM.