The Future of TCP/IP Always evolving: –New computer and communication technologies More powerful PCs, portables, PDAs ATM, packet-radio, fiber optic, satellite, cable –New applications WWW, electronic commerce, internet broadcasting, chat –Increased size and load –New policies New industries, new countries Move away from centralized core architecture

The Future of IP IP version 4 (IPv4) has been in use since the 1970’s IPv4 is being replaced: –Address space exhaustion Running out of 32-bit IP addresses –Support new applications Electronic commerce - authentication Audio/video - Quality of Service (QoS) guarantees –Decentralization

The Next Version of IP Work on an open standard has been underway for years –Add functionality to IPv4 –Modify OSI CLNS –Simple IP Plus (SIPP) - simple extensions to IPv4 IP - The Next Generation (Ipng) IPv6

Details available at: Major similarities with IPv4: –Connectionless datagram delivery –TTL, IP options, fragmentation Major differences from IPv4: –Larger address space 128-bit IPv6 IP addresses –New datagram format

IPv6 (cont) IPv4 - fixed-size header, variable-length options field, variable length data field: IPv6 - a set of variable-length (optional) headers: VERS (4) HLEN SERVICE TYPE TOTAL LENGTH IDENTIFICATION FLAGS FRAGMENT OFFSET TIME TO LIVE PROTOCOL HEADER CHECKSUM SOURCE IP ADDRESS DESTINATION IP ADDRESS DATA IP OPTIONS (IF ANY) PADDING VERS (6) TRAFFIC CLASS FLOW LABEL PAYLOAD LENGTH NEXT HEADER HOP LIMIT SOURCE IP ADDRESS DESTINATION IP ADDRESS

IPv6 Extension Headers IPv6 datagram format: –Fixed-size base header –Zero or more variable-length extension headers –Variable-length data (or payload) segment BASEEXTENSION….EXTENSION DATA HEADERHEADER 1HEADER N

IPv6 Extension Headers (cont) Zero extension headers One Extension header Two extension headers Base Header Next=TCP TCP Segment Base Header Next=Route TCP Segment Route Header Next=TCP Base Header Next=Route TCP Segment Route Header Next=Auth Auth Header Next=TCP

Security in IPv6 Based on two mechanisms: –Authentication Header (AH) Proof of the sender’s identity Protection of the integrity of the data –Encapsulating Security Payload (ESP) Protection of the confidentiality of the data

Authentication Header - Example Base Header Next=Auth TCP Segment Auth Header Next=TCP

Authentication Header Security parameters index field – specifies which specific authentication scheme is being used Authentication data field – contains data that can be used to establish the datagrams: –Authenticity –Integrity

Encapsulating Security Payload Encryption of the datagram or part of the datagram 2 modes: –Transport mode – encryption of datagram payload –Tunneling mode Encryption of entire datagram Encapsulation of datagram

ESP Transport Mode Encryption of payload for privacy: Base Header Next=ESP Encrypted TCP Segment ESP Header Next=TCP ESP Trailer Security Parameter IndexSequence Number Padding Pad Len Next Header ESP Auth Data (Var)

ESP Tunnel Mode Encryption of entire datagram for privacy Base Header Next=ESP Encrypted Datagram ESP Header Next=IP

AH and ESP Protect authenticity, integrity, and privacy:

IPv6 (cont) Major differences from IPv4: –Improved Options More flexibility and new options –Support for resource allocation Packets labeled as belonging to particular traffic flow Sender requests special handling (e.g. Qos, real-time, etc.) –Authentication, data integrity, and data confidentiality supported –Provision for protocol extension

IPv6 Fragmentation IPv4 –Intermediate router fragments datagram when necessary –Ultimate destination reassembles IPv6 - end-to-end fragmentation –Before sending a datagram, source must determine the path’s MTU –Source fragments the datagram –Ultimate destination reassembles

IPv6 Fragmentation (cont) End-to-end fragmentation –Advantages –Disadvantages

Representing IPv6 Addresses 128-bits –Binary: –Dotted decimal: –Hex-colon: 1:8203:FFC5:E00:807F:3083:0:0

Representing IPv6 Addresses (cont) 128-bits –Compressed hex-colon format Zero compression –A string of repeated zeroes is replaced by a pair of colons –Performed at most once per address (unambiguous) Examples: –FF05:0:0:0:0:0:0:B3 = FF05::B3 –0:0:0:0:0:0:E00:807F = ::E00:807F –0:0:0:F6AD:0:0:0:0 = 0:0:0:F6AD::

IPv4 Addresses Assignment Class A Class B Class C 0 netid hostid netid hostid netid hostid

IPv6 Address Assignment Binary PrefixType of AddressPart of Address Space Reserved (IPv4 compatible)1/ Reserved1/ NSAP Addresses1/ IPX Addresses1/ Reserved1/128 … Reserved1/ Reserved1/16 001Reserved1/8 010Provider-assigned unicast1/8 011Reserved1/8 100Reserved for geographic1/8 101Reserved1/8 110Reserved1/8 1110Reserved1/ Reserved1/ Reserved1/ Reserved1/ Available for local use1/ Multicast1/256

IPv6 Address Types Unicast –Specifies a single computer Cluster/Anycast –Specifies a set of computers that share an address prefix (possibly at multiple locations) Multicast –Specifies a set of computers (possibly at multiple locations)

IPv6 Address Hierarchy Address type prefix Provider prefix Subscriber prefix Subnet prefix IPv6 address 010 Provider ID Subscriber ID Subnet ID Node ID