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

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

Three reason why IPv6 is needed?

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

What techniques does IPv4 utilize to fix address exhaustion?

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

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

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

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

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

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

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

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 ask audience about efficiency.

Unchanged Fields

Equivalent Fields - address 32 to 128 bits - total length => payload - protocol => next header - TTL => hop limit

Removed Fields

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.

Header Comparison Removed (6) Changed (3) IPv4 Added (2) Expanded IPv6 15 16 31 Removed (6) vers hlen TOS total length ID, flags, flag offset TOS, hlen header checksum identification flags flag-offset 20 bytes TTL protocol header checksum 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

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

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

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

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

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

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

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

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

Flow Labels Default Flow Label 0 Otherwise Random value from 0 to 0xFFFFF 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

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

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

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

Questions?