1. IPv6 The New Internet Protocol Integrated Network Services Almerindo Graziano

2. Introduction Justification for IPv6 IPv6 goals IPv6 Addressing The new Header –Extension Headers Recap

3. Justification for IPv6: What is wrong with IPv4? Wasteful of address space Not built-in support for hierarchical addressing –Subnetting –CIDR Large routing tables Large administrative workload: –Changing ISP –Merger or acquisition Renumbering or NAT

4. What is wrong with IPv4? Routers perform a lot of operations –Table lookup –Options –Checksum –Fragmentation Lack of authentication –IP spoofing Lack of encryption

5. IPv6 goals Support for a larger number of addresses Reduce the size of routing tables Simplify the protocol (easier to process) Provide better security Better support for Quality of Service Provide support for mobile users Allow the protocol to be extensible Be compatible

6. IPv6 Addressing scheme Designed to be highly scalable and hierarchical 16-byte long –7x10 23 IP addresses per square meter!!! –It “eliminates” the need for private address space IPv6 notation 8000:0000:0000:0000:0123:8219:E42A:DF3E 8000::123:8219:E42A:DF3E IPv4 addresses can be written as ::192.31.20.46

7. Address Allocation IPv6 could support a number of diverse addressing schemes –Provider Allocation hierarchy is based on large service providers, regardless of their location –Geographic Allocation hierarchy is based on the location of subscribers (similar to the telephony system) Both approaches have drawbacks Large networks do not often conform to provider and/or geographical boundaries!!

8. Aggregation Based Allocation Combines provider and geographic allocation approaches –Based on the existence of limited number of high-level exchange points Large providers are represented at one or more exchange points (provider orientation) –Exchanges are distributed around the globe (geographic orientation) Favoured by the IETF

9. IPv6 Address Hierarchy To other TLA Long-Haul Provider Interexchange (TLA) Subscriber Provider Subscriber Provider Subscriber Long-Haul Provider TLA: Top Level Aggregator

10. Aggregation-based Allocation First 3 bits identify the type of address –unicast, multicast, anycast etc.. International registries assign block to TLA TLA allocate block of addresses to NLA –NLA can be large providers or global corporate networks NLA can create their own hierarchy 001 TLA RES NLA SLA Interface ID 3 13 8 24 bits 16 bits 64 bits Public Topology Local InterfaceSite Topology IEEE EUI-64 Address 24 bits - Company ID 40 bits - interface ID

11. NLA 1 NLA 2 NLA 3 Site SLA Interface ID 32 bits Aggregation-based Allocation

12. Other Address Types Site-Local Addresses –Similar to IPv4 private addresses Link-Local Addresses –A router doesn’t exist –Operate over a single link –Used for temporary bootstrapping Not propagated outside organizational boundaries Not allocated by public registry authorities 1111111010 00. …. 00 Interface ID 128 bits 54 bits64 bits10 bits

13. Other Address Types Multicast Addresses –Logical addresses to communicate to multiple nodes Anycast Addresses –Used to communicate to the closest of a class of nodes (closest DNS, closest router) –Allocated from the same address space as Unicast addresses

14. Address Autoconfiguration A node combines its MAC address with a network prefix it learns from a neighbouring router The autoconfiguration doesn’t need a manually configured server: stateless address autoconfiguration –It differs from IPv4’s DHCP (stateful address configuration). DHCPv6 has been developed –Great advantage when an enterprise is forced to renumber because of an ISP change or M&A –Great support for mobile users and dynamic workgroups

15. 32 bits Source Address Destination Address Version PriorityFlow Label Payload Length Next Header Hop Limit IPv4 Header IPv6 Header Header Comparison Version Type of Service IHLTotal Length Identification Flag Fragment Offset TTLProtocolHeader Checksum Source Address Destination Address Options Padding 32 bits IPv4 Header = 14 fields IPv6 Header = 8 fields

16. The new Header Fixed size Fewer fields No Checksum –Already performed by other layers –Reliable networks Extension Headers replace Options –Routers can skip over some extension headers Faster processing Extensible

17. QoS Support Priority field (4 bits) –Congestion-Controlled traffic (0-7) Traffic where the source backs off in case of congestion (e.g. TCP) –Non-Congestion-Controlled traffic (8-15) Traffic where constant data rate and delay are desirable (real-time audio/video) Flow label field (20 bits) –A sequence of packets sent from a particular source to a particular destination for which the source desires special handling by intervening routers

18. Extension Headers Ê Hop-by-Hop options header Ë Destination options header-1 Ì Source Routing header Í Fragmentation header Î Authentication header Ï IPv6 Encryption header Ð Destination options header-2

19. Extention Headers Hop-by-Hop –Carries information for all intermediate nodes –Used for management and debugging Destination –Carries information to be read just by destination nodes Source Routing –Allows to specify a list of router to traverse

20. Fragmentation Header Each source is responsible for sending packets of the right size –MTU path discovery process Packet fragmentation is not permitted by intermediate nodes (routers) –Faster processing If fragmentation is required, the fragmentation header is used

21. Authentication Header It gives network applications a guarantee that a packet did in fact come from an authentic source A checksum is created based on the key and the content of the packet The checksum is re-run at the destination and validated

22. IPv6 Encryption Header Encapsulation Security Payload (ESP) –It provides encryption at the network layer Two encryption modes are supported –Transport mode –Tunnel mode (steel pipe)

23. Encryption modes IPv6 Header Extention Headers ESP Header Transport Header and Payload UnencryptedEncrypted IPv6 Header Extention Headers ESP Header IPv6 Header Extention Headers Transport Header and Payload UnencryptedEncrypted Original IP packet Transport Mode Tunnel Mode

24. The Transition to IPv6 IPv6 offers a robust future-oriented solution to integrate physical networks Possibly use NAT but –can be a bottleneck –prevents the use of IP-level security –breaks Domain Name Servers 6Bone –Experimental world-wide network for testing IPv6

25. IPv6 Resources –Main IPv6 page http://ipv6.com/ –6Bone home page http://6bone.net/ –The case for IPv6 (Internet Draft) http://www.6bone.net/misc/case-for-ipv6.html