Next Generation: Internet Protocol, Version 6 (IPv6) RFC 2460

1. Next Generation: Internet Protocol, Version 6 (IPv6)RFC 2460 Geller Bedoya Joe Contreras Stephen Ward Michael Yue

2. RFC 2460 Basic IPv6 header Initially-defined IPv6 extension headers and options

3. Three reason why IPv6 is needed?

4. Deficiencies of IPv4 • IPv4 address exhaustion • Internet must accommodate • Real-time audio • Video transmission • No encryption or authentication is provided in IPv4

5. What techniques does IPv4 utilize to fix address exhaustion?

6. Techniques to Reduce Address Shortage in IPv4 Subnetting Classless Inter Domain Routing (CIDR) Network Address Translation (NAT)

7. Features of IPv6 Larger Address Space Aggregation-based address hierarchy Efficient backbone routing Efficient and Extensible IP datagram Stateless Address Autoconfiguration Security IPsec mandatory Mobility

8. Expanded Addressing Capabilities • IPv6 increases the IP address size from 32 bits to 128 bits • ~3.4×10^38 addresses • More devices, more addressable nodes • simpler auto-configuration of addresses. • Improvement to/addition of: • Multicasting • Anycasting

9. 128-bit IPv6 Address 3FFE:085B:1F1F:0000:0000:0000:00A9:1234 8 groups of 16-bit hexadecimal numbers separated by “:” Leading zeros can be removed 3FFE:85B:1F1F::A9:1234 :: = all zeros in one or more group of 16-bit hexadecimal numbers

10. Multicast Addressing • Allow a single device to send a datagram to a group of recipients • Denoted by a preface of 0xFF in the address(1/256 of the address space) • Field is broken into four fields: • Indicator field – 8 Bits • Flags - 4 bits (000X) X=1, Transient • Scope ID – 4 bits • Group ID – 112 bits

11. Anycast Addressing Identifier for a set of interfaces Packets are routed to the closest interface depending upon distance Path may change if network configuration changes

12. Header Format Simplification • Since the headers of IPv4 and IPv6 are significantly different • The two protocols are not interoperable • Some IPv4 header fields have been dropped or made optional

13. Simplified Header Format • Description • IPv6: Eight fields spread over 40 bytes • IPv4: at least 12 fields • From 20 until 60 bytes • Improves routing efficiency • Uniformly sized header • Fewer fields to examine and process

14. Unchanged Fields

15. Equivalent Fields

16. Removed Fields

17. Major Improvements of IPv6 Header No option field Replaced by extension header. Result in a fixed length, 40-byte IP header No header checksum Result in fast processing No fragmentation at intermediate nodes Result in fast IP forwarding.

18. Header Comparison 15 16 31 0 Removed (6) vers hlen TOS total length • ID, flags, flag offset • TOS, hlen • header checksum identification flags flag-offset TTL protocol header checksum 20 bytes source address destination address Changed (3) options and padding • total length => payload • protocol => next header • TTL => hop limit IPv4 vers traffic class flow-label Added (2) payload length next header hop limit • traffic class • flow label 40 bytes source address Expanded destination address • address 32 to 128 bits IPv6

19. IP Header Options Optional information is placed in separate headers that are placed between the IPv6 header and the next layer header Makes use of the Next Header field

20. Length of Options Use of the Next Header field allows for more flexibility with the length of options.

21. Current Extension Headers Hop-by-Hop Options – Examined at every node along the delivery path Routing – Lists nodes to visit along the delivery path Fragment – Facilitates fragmentation for packets larger than a path’s MTU Destination Options – Contains information that needs to be examined by the destination

22. Advantages • More efficient forwarding • Only processed as necessary • Less stringent limits on the length of options • Flexibility for future options • Easier to define new extensions

23. Stateless Address Autoconfiguration(SLAAC) • Motivation • Host self-configuration • Performed using IMCPv6 • RFC 4443 • 3 ways to configure network interfaces: • Stateless • Stateful • Manually

24. Stateless Address Autoconfiguration(SLAAC) Router Solicitation HOST NEW HOST HOST Router Advertisement HOST ROUTER NEW HOST • ICMPv6 router discovery messages

25. Stateless Address Autoconfiguration(SLAAC) • If Stateless addressing not suitable stateful addressing is used • DHCPv6 (RFC 3315) • Or else manual configuration is performed

26. Flow Labeling Capability • A new capability is added to enable the labeling of packets • Belonging to particular traffic "flows" for which the sender requests special handling • Motivation • Non-default Quality of Service or real-time service

27. Flow Labels • Default • Flow Label 0 • Otherwise • Random value from 0 to 0xFFFFF 0 3 4 11 12 31 vers traffic class flow-label payload length next header hop limit Flow 1 40 bytes source address Flow 1: destination address IPv6

28. Traffic Class • Distinguish different classes and priorities of packets • Provide similar functionality to Type of Service (ToS) from IPv4 0 3 4 11 12 31 vers traffic class flow-label payload length next header hop limit 40 bytes source address destination address IPv6

29. Authentication and Privacy Capabilities • Extensions to support • Authentication • Data integrity • Data confidentiality • IPv6 specifications mandate IPsec • Third-generation documents • RFC 4301 & RFC 4309

30. Mobility of IPv6 • Large Address Space • Can support billions of mobile devices • Automatic Link Configuration • Neighbor discovery on home and visited networks • Stateless and Stateful address configuration

32. Questions?