IPv6 Technology Overview

IPv6 Technology Overview David Otero University of San Diego MSIT 526 Dr. Carl Rebman

Scope • IPv6 Background • Current Internet Assigned Numbers Authority (IANA) IPv4 Allocation • Classless Inter-Domain Routing (CIDR) • Network Address Translation (NAT) • IPv6 Details • 6bone and Internet2 • IPv6 Features • Migration Schemes • Routing • Cost Considerations • Conclusion

IPv6 Background • Internet services demand continues to grow, at an all time high • IP addresses are required for new hosts • Current IP implementation is limited to theoretical max of ~4 billion addresses • There are parts of the IPv4 address scheme that have bee assigned to alternate uses and can not be allocated for use on the public Internet: • Class D IPv4 Multicast Scope (224.0.0.0-239.255.255.255) • Class E IPv4 Experimental Scope (240.0.0.0-254.255.255.255) • RFC 1918 Private Scoped Addresses • 10.0.0.0-10.255.255.255 /8 • 172.16.0.0-172.31.255.255 /12 • 192.168.0.0-192.168.255.255 /16

IPv6 Background • Addresses available within the IPv4 scheme are also hampered by the mismanagement of Class A address spaces during the early inception of the Internet • During the 1980s, large corporations and educational organizations were given Class A address spaces even though they only had a small amount of computers or endpoints to manage • The resulting effect is that countries in Asia, Africa, and Europe receive only a single Class C because they requested an IPv4 range so late

Current IANA IP Allocation • The pool of IP addresses is managed by the IANA • Blocks of addresses are allocated to Regional Internet Registries (RIRs), who in turn allocate smaller blocks to Local Internet Registries (LIRs) or Internet Service Providers (ISPs) • Currently 3,707,764,736 addresses are managed in this way • It is probably easier to look at this in terms of the number of /8 blocks, where each block is the same size as the old Class A network, or 16,777,216 addresses • The total address pool is 221 /8s, with a further 16 /8s reserved for multicast use, 16 /8s held in reserve, and 3 /8s designated as not for use in the public Internet

Current IANA IP Allocation Figure 1 below shows the number of currently allocated IPv4 blocks:

Current IANA IP Allocation Figure 2 demonstrates the predicted growth and predicted exhaustion time line of /8 blocks:

Internet Routing Tables • The global Internet routing table is huge and continues to grow rapidly over time • A larger global Internet routing table can have a negative impact on the performance of core Internet routers, therefore slowing down performance • There have been attempts to mitigate the rapid growth of the routing tables, such as Classless Inter-Domain Routing (CIDR) • CIDR is a variation of the traditional class-based IPv4 addressing scheme that classifies IPv4 ranges into classes • CIDR is used in route aggregation to group a range of IPv4 networks in to one single statement (assuming they are sequential) • A slash followed by a number represents the number of bits in the IPv4 address that are included in the range: • 192.168.0.0 /16 represents 192.168.0.0 through 192.168.255.255

CIDR • Route aggregation is an important item in extending IPv4 because it reduces the number of routes in the core Internet router infrastructure; by aggregating and combining routes, the less overhead is placed on the routers • The Internet routing tables are most commonly propagated between ISPs via the Border Gateway Protocol (BGP) • A good measure of the Internet’s growth is the number of BGP routes contained in the Internet’s core routers

CIDR Figure 3 demonstrates the rapid growth of the Internet BGP routing tables telnet://12.0.1.28/

NAT • Network Address Translation (NAT) has played a major role in extending the capabilities of the existing IPv4 address space • NAT works by translating IPv4 private addresses, as defined by RFC 1918 into publicly routable, globally unique addresses • There are some limitations in the NAT framework, they include the following • NAT violates IP’s end-to-end model • Need to keep connection states • End-to-end network security

History of IPv6 • All of the listed limitations of IPv4 prompted IETF to act • RFC 1550 released 1993 • IANA assigned the version number 6 to the protocol • A working group at the IETF called IP Next Generation (IPng) was started in 1993 • The first specification from the IPng working group came in late 1995 in the form of RFC 1883 • The IPng group was renamed IPv6 in 2001

6bone and Internet2 • In 1996, and IPv6 test bed called the IPv6 backbone (6bone) was created over the public Internet • 3ffe::/16 • Over the last two years, the Internet2 IPv6 Working Group has succeeded in deploying an IPv6 network within the Abilene infrastructure

IPv5 • Internet Protocol version 5 is an experimental reservation protocol intended to provide Quality of Service (QoS), and is defined as Internet Stream Protocol (ST) • IPv5 is also referred to as ST2 • ST2 is not a replacement to IPv4, but is designed to run in parallel with IPv4

IPv6 Address Space • The 128 bit length of IPv6 allows for 3.4E+38 addresses • Having a large address space in IPv6 enables the use of a multi-leveled hierarchal addressing model that simplifies address allocation for ISPs • Same effect as CIDR in IPv4

IPv6 Address Assignment • IPv6 supports a feature called autoconfiguration or stateless address autoconfiguration • A client or node on a network can self-configure a unique IPv6 address • This is done by having an IPv6 enabled router on the local network advertising route information to the local hosts • IPv6 hosts can also obtain an address via a DHCPv6 server • This is referred to as stateful address configuration • Manual configuration is also an option as it was with IPv4 • Manual configuration is still required for most routers and is usually a good idea for servers as well

Multicast and Features • Elimination of broadcasts for address resolution (ARP) • IPv6 utilizes multicast addresses for MAC to IP address resolution by having each host listen on a specific multicast address, which is comprised of its IPv6 address and MAC • Also used for Duplicate Address Detection, Neighbor Discovery, ICMP • The new IPv6 header is simpler than the IPv4 header, consisting of only eight fields as opposed to 14 fields • Less computer processing time by routers and hosts along the network path • The checksum calculation used by IPv4 to verify a packet’s integrity has also been removed • Optional fields such as flow labels, enhances QoS implementations

Security • Was afterthought in IPv4, now integrated into IPv6 • Covered by IPSec protocol • There are two main protocols within the IPSec framework: Authentication Header (AH) and Encapsulation Security Payload (ESP)

Migration Schemes • Dual Stacking • Example: IPX and IP • Application has to be written and designed to call up the Application Program Interface (API) for the IPv6 protocol stack • Tunneling • The configured tunnel is a static tunnel between two pre-defined routers that are dual stacked • IPv6 traffic is simply encapsulated in an IPv4 header and transported over the tunnel • Automatic tunneling, or 6to4 tunnels, are tunnels that dynamically established between endpoints that are 6to4 enabled. The 6to4 routers will have an internal IPv6 network and when traffic from theses networks are transmitted to an external IPv6 hosts, a lookup is done against the IPv6 routing table. The packets are then encapsulated in IPv4 and transmitted to the destination • 2002::/16 Address Range

Migration Schemes • NAT-PT • NAT-PT is a feature that translates IPv6 addresses into IPv4 addresses and vice-versa • NAT-PT is not a long term solution, just as NAT is not a long term solution to the IPv4 scalability problems • It should only be used when there is no other method to have an IPv6 network communicate with an IPv4 network

IPv6 Routing • Same as in IPv4 • Router conducts longest-match lookup against routing table • Static Routing • Administrator manually enters a route into the router’s table with the information required for a router to make a forwarding decision for the networks in question, not scalable • Dynamic Routing • Protocol share routing information between routers • IGP: OSPFv3, RIPng, IS-IS • EGP: BGP4+

IPv6 Costs • Specifying the costs associated with upgrading to IPv6 is difficult because most companies will take a phased approach to the matter, will absorb the costs over time • Since IPv6 implementations are still in their infancy, there are no detailed case studies to look at when calculating these costs • A recent study conducted by Juniper Networks and the US IPv6 Summit suggests that the entire IPv4-to-IPv6 transition costs for the entire US could range from $25 to $75 Billion • The Federal government has dictated a cutover date of June 2008, but other industries have not committed to such an aggressive schedule • This puts estimates for a complete cutover to IPv6 on a range from 8 to 20 years

IPv6 Product Support • There are many Operating System and application vendors’ products that currently support IPv6 in their existing products • Microsoft supports IPv6 by including support into their flagship OS Windows XP • There is an IPv6 stack available for the older Windows NT and Windows 2000 server and client, although they are considered experimental and only previews to the fully supported implementation in Windows 2003 server • The Microsoft implementation includes application support for their core business apps and added tools such as Telnet, FTP, ping, nslookup, tracert, Domain Name Server (DNS) resolver, and file and print sharing • IPv6 support also includes Internet Explorer, ,NET Server, Internet Information Server (IIS), Microsoft Media Server, and Microsoft Remote Procedure Call (RPC) • In theory, any RPC-based application should run over IPv6

IPv6 Product Support • There are many other Operating Systems that support IPv6, including Linux, FreeBSD, Sun Solaris, and Tru64… • Most of the major telecommunications and data networking equipment manufacturers support IPv6 in their current platforms • Companies such as Cisco, Nortel, Juniper, and Alcatel have had IPv6 products on the market for some time

IPv6 ISPs • IPv6 Internet is already in production • Small compared to IPv4 backbone • In order to connect to the IPv6 Internet, it is necessary to locate an ISP that is a registered RIR • Currently in North America, there are not that many IPv6 RIRs when compared to Asia and Europe • Some examples of Tier-1 ISPs include MCI’s vBNS network, as well as NTT’s North America IPv6 point of presence in Dallas http://www.6bone.net/

Conclusion • One of the strengths of IPv6 is its large range of features designed to ease the migration from IPv4 to IPv6. • These migration techniques allow for some level of inter-operability between the two protocols • Most importantly, they make it possible to implement IPv6 in phases, one host at a time • The migration from an IPv4-networked world to an IPv6-enabled world also continues at a steady pace • The migration will take years and the costs associated will more than likely be absorbed by companies over an extended period of time • The need to replace IPv4 has been known for a long time now, and this foresight will allow companies to institute a well-planned and coordinated migration plan

This Concludes the Presentation Any Questions?

IPv6 Technology Overview