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IPv6
- 1. Internet Protocol version 6 Dept. IT,GNIT
- 2. Table of Contents • • • • • • • • • • • Introduction Why we need IP address? Review of IPv4 Why another version of IP Features of IPv6 address Types of IPv6 address. IPv6 addressing Transition mechanism Advantages over IPv4 Disadvantages of IPv6 Conclusion Dept. IT,GNIT
- 4. Why we need IP address?? Dept. IT,GNIT
- 5. Review of IPV4 It was developed in the early 1980s & served the global Internet community for more than 3 decades . IPv4 has more than 4 billion unique IP addresses but nearly 3.7 billion IPv4 addresses are used by ordinary internet access devices . The others are used for special protocols, like IP Multicasting . Mainly, due to the need of more IP addresses, IPv6 is replacing IPv4 addresses . Dept. IT,GNIT
- 6. Why another version?? Dept. IT,GNIT
- 7. Features of IPV6 • • • • • Dept. IT,GNIT
- 9. Types of IPv6 Addresses •Unicast Addresses The packet sent to a unicast address must be delivered to the specific computer. •Multicast Addresses The packet sent to a multicast address must be delivered to the each member of the group. •Anycast Addresses The packet sent to a anycast address is delivered to only one of the member of the group,the nearest one. Dept. IT,GNIT
- 10. IPV6 Addressing • 128 bit vs. 32 bit •Notation: Dept. IT,GNIT
- 11. •Abbreviation: •IPv6 addresses in URL: http://[2001:cdba:0000:0000:0000:0000:3257:9652]/ Dept. IT,GNIT .
- 12. Transition Mechanism Till now IPV6 is not globally accepted. So transition is needed form IPV4 to IPv6. Three strategies are… •Dual Stack All hosts must have a dual stack of protocols before migrating completely to version 6. DNS determines which version to use when sending a packet. Application Layer Transport Layer (TCP/UDP) IPv4 IPv6 Underlying LAN or WAN Dept. IT,GNIT
- 13. •Tunneling Two computer using IPV6 want to communicate with each other and the packet must pass through an IPv4 region. The IPv6 packet is encapsulated in an IPv4 packet when it enters the region and leaves its capsule when its exits the region. •Header Translation When the majority of the Internet has moved to IPv6 but some system still use IPv4. The header format must be converted to IPv4. It uses the mapped address to translate an IPv6 address to an IPv4 address. Dept. IT,GNIT
- 14. Advantages over IPV4 Dept. IT,GNIT
- 15. Advantages over IPV4(cont.) • Dept. IT,GNIT
- 16. Disadvantages of IPV6 Dept. IT,GNIT
- 19. References www.omnisecu.com www.ipv6.com www.ietf.com Data Communications and Networking Behrouz A Forouzan Dept. IT,GNIT
Notes de l'éditeur
- The Internet Protocol Version 4 (IPv4) is defined by IETF RFC 791. RFC 791 was published in 1981. Initial design of IPv4 did not anticipate the growth of internet and this created many issues, which proved IPv4 need to be changed. The main limitations of IPv4 are listed below.• Scarcity of IPv4 Addresses: The IPv4 addressing system uses 32-bit address space. This 32-bit address space is further classified to usable A, B, and C classes. 32-bit address space allows for 4,294,967,296 IPv4 addresses, but the previous and current IPv4 address allocation practices limit the number of available public IPv4 addresses. Many addresses which are allocated to many companies were not used and this created scarcity ofIPv4 addresses.Because scarcity of IPv4 addresses, many organizations implemented NAT (Network Address Translation) to map multiple private IPv4 addresses to a single public IPv4 address. By using NAT (Network Address Translation) we can map many internal private IPV4 addresses to a public IPv4 address, which helped in conserving IPv4 addresses. But NAT (Network Address Translation) also have many limitations. NAT (Network Address Translation) do not support network layer security standards and it do not support the mapping of all upper layer protocols. NAT can also create network problems when two organizations which use same private IPv4 address ranges communicate. More servers, workstations and devices which are connected to the internet also demand the need for more addresses and the current statistics prove that public IPv4 address space will be depleted soon. The scarcity of IPv4 address is a major limitation of IPv4 addressing system.• Security Related Issues: As we discussed before, RFC 791 (IPv4) was published in 1981 and the current network security threats were not anticipated that time. Internet Protocol Security (IPSec) is a protocol suit which enables network security by protecting the data being sent from being viewed or modified. Internet Protocol Security (IPSec) provides security for IPv4 packets, but Internet Protocol Security (IPSec) is not built-in and optional. Many IPSec implementations are proprietary.• Address configuration related issues: Networks and also internet is expanding and many new computers and devices are using IP. The configuration of IP addresses (static or dynamic) should be simple.• Quality of service (QoS): Quality of Service (QoS) is available in IPv4 and it relies on the 8 bits of the IPv4 Type of Service (TOS) field and the identification of the payload. IPv4 Type of Service (TOS) field has limited functionality and payload identification (uses a TCP or UDP port) is not possible when the IPv4 datagram packetpayload is encrypted.
- New Packet Format and Header: IPv6 specifies a new packet format. The new IPv6 packet format helps to minimize packet header processing by routers. This is achieved by moving both nonessential and optional fields to extension headers that are placed after the IPv6 header. Since IPv4 packets and IPv6 packets are significantly different, the two protocols are not interoperable.• Large Address Space: IPv4 has 32 bit (4-byte) address space, but IPv6 has 128-bit (16-byte) address space. The very large IPv6 address space supports a total of 2128 (3.4×1038) addresses. This large address space allow a better, systematic, hierarchical allocation of addresses and efficient route aggregation. With the large number of available addresses we can eliminate address-conservation techniques like NAT (Network Address Translation).• Statefull and Stateless IPv6 address configuration: In IPv6 statefull or stateless configuration is possible. Hosts on a link can automatically configure with IPv6 addresses called link-local addresses and with addresses derived from prefixes advertised by local routers. When first connected to a network, a host sends a link-local router solicitation multicast request for its configuration parameters. The router which is available in the link responds to the request from the host with a router advertisement packet that contains network-layer configuration parameters. Hosts can configure link-local addresses automatically and communicate each other without manual configuration even there is no router available. The hosts may also have stateful configuration with the Dynamic Host Configuration Protocol version 6 (DHCPv6) or static configurations, as IPv4.• Multicast: The three types of communication available in in IPv4 are unicast, multicast and broadcast. Unicast is one-to-one communication; multicast is one-to-many communication and broadcast is one-to-all communication. The transmission of a packet to all hosts was performed by using special broadcast addresses in IPv4. Broadcast communication is not available in IPv6 and therefore does not define broadcast addresses. In IPv6, the effect of broadcast can be achieved by sending a packet to the link-local all nodes multicast group at address ff02::1.
- Integrated Internet Protocol Security (IPSec): Internet Protocol Security (IPSec) is a set of Internet standards that uses cryptographic security services to provide Confidentiality, Authentication, Data integrity. The support for Internet Protocol Security (IPSec) was optional in IPv4. Internet Protocol Security (IPSec) is an integral part of the base protocol suite in IPv6. Internet Protocol Security (IPSec) support is mandatory in IPv6.• Neighbor Discovery Protocol: The Neighbor Discovery Protocol (NDP) is a protocol available IPv6. The Neighbor Discovery protocol (NDP) is based on Internet Control Message Protocol Version 6 (ICMPv6) messages that manage the interaction nodes on the same link. There is no Address Resolution Protocol (ARP) for IPv6 and the role of the Address Resolution Protocol (ARP) is replaced by Neighbor Discovery Protocol (NDP).• Extensibility: The features of IPv6 can be extended by adding extension headers after IPv6 header. The size IPv6 extension headers is constrained only by the size of the IPv6 datagram packet, unlike 40 bytes of options of IPv4.• Jumbograms: Jumbograms is an optional feature of IPv6. Jumbograms allow packets with payloads 2^32 - 1 (4,294,967,295) bytes by making use of a 32-bit length field.
- Forouzan (page no. 569)
- Forouzan 4th Ed. PAGE NO> 567
- Forouzan 4th Ed. PAGE NO> 603
- More Efficient RoutingIPv6 reduces the size of routing tables and makes routing more efficient and hierarchical. IPv6 allows ISPs to aggregate the prefixes of their customers' networks into a single prefix and announce this one prefix to the IPv6 Internet. In addition, in IPv6 networks, fragmentation is handled by the source device, rather than the router, using a protocol for discovery of the path's maximum transmission unit (MTU).MulticastIPv6 supports multicast rather than broadcast. Multicast allows bandwidth-intensive packet flows (like multimedia streams) to be sent to multiple destinations simultaneously, saving network bandwidth. Forouzan 678(Uni,Broad and Multicast)More Efficient Packet ProcessingIPv6's simplified packet header makes packet processing more efficient. Compared with IPv4, IPv6 contains no IP-level checksum, so the checksum does not need to be recalculated at every router hop. Getting rid of the IP-level checksum was possible because most link-layer technologies already contain checksum and error-control capabilities. In addition, most transport layers, which handle end-to-end connectivity, have a checksum that enables error detection.
- SecurityIPSec, which provides confidentiality, authentication and data integrity, is baked into in IPv6. Because of their potential to carry malware, IPv4 ICMP packets are often blocked by corporate firewalls, but ICMPv6, the implementation of the Internet Control Message Protocol for IPv6, may be permitted because IPSec can be applied to the ICMPv6 packets.Support For New ServicesBy eliminating Network Address Translation (NAT), true end-to-end connectivity at the IP layer is restored, enabling new and valuable services. Peer-to-peer networks are easier to create and maintain, and services such as VoIP and Quality of Service (QoS) become more robust.Stateless auto Configuration Stateless Auto Configuration is an important feature offered by the IPv6 protocol. It allows the various devices attached to an IPv6 network to connect to the Internet using the Stateless Auto Configuration without requiring any intermediate IP support in the form of a Dynamic Host Configuration Protocol (DHCP) server. A DHCP server holds a pool of IP addresses that are dynamically assigned for a specified amount of time to the requesting node in a Local Area Network (LAN). Earlier, configuration of the IP addresses was a manual process requiring support of a DHCP server. However, IPv6 allows the network devices to automatically acquire IP addresses.Mobile IPV6Mobile IPv6 is an IETF standard that has added the roaming capabilities of mobile nodes in IPv6 network. The major benefit of this standard is that the mobile nodes (as IPv6 nodes) change their point-of-attachment to the IPv6 Internet without changing their IP address. This allows mobile devices to move from one network to another and still maintain existing connections. Although Mobile IPv6 is mainly targeted for mobile devices, it is equally applicable for wired environments. .
- Disadvantages of IPv6 - While, on the whole, IPv6 should be a beneficial upgrade to the current Internet, there are some noticeable disadvantages. In particular, the four-number IP addresses of today are relatively easy to remember, although few non-specialists have any need to. In the future, under IPv6, this will become increasingly impossible to do given the size of the address (see above). In addition, and more seriously, there still seems to be no clear plan for how the transition from IPv4 to IPv6 will actually occur. Recent versions of all major operating systems, including Microsoft Windows, Apples Mac OS X, and Linux, do incorporate support for IPv6. It is less clear how Internet service providers will make the transition. The degree of backwards-compatibility between the two is limited, and if we continue to run through the limited unallocated addresses available as quickly as we currently are, the time available for a slow, orderly transition is limited. Complete chaos is unlikely, but a painful transition involving a series of tricky and occasionally buggy workarounds is quite conceivable. Ideally, most of this will occur behind the scenes, so that the average consumer does not realize that a transition is occurring. Obviously, the more complicated and flawed the process, the more inconveniences will be caused to end users.