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

IPv6

• Details available at: http://playground.sun.com/pub/ipng/html/ipng-main.html

• 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

BASE EXTENSION …. EXTENSION DATA

HEADER HEADER 1 HEADER 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 SegmentESP Header Next=TCP

ESP Trailer

Security Parameter Index

Sequence Number

Padding Pad Len Next Header

ESP Auth Data (Var)

ESP Tunnel Mode

• Encryption of entire datagram for privacy

Base Header Next=ESP

Encrypted DatagramESP 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:

00000000 00000001 10000010 00000011 11111111 11000101 00001110 00000000 00001000 01111111 00110000 10000011 00000000 00000000 00000000 00000000

– Dotted decimal:0.1.130.3.255.197.14.0.8.127.48.131.0.0.0.0

– 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 hostid0 8 16 24 31

0 8 16 24 31

0 8 16 24 31

1 0 netid hostid

1 1 0 netid hostid

IPv6 Address Assignment

Binary Prefix Type of Address Part of Address Space0000 0000 Reserved (IPv4 compatible) 1/2560000 0001 Reserved 1/2560000 001 NSAP Addresses 1/1280000 010 IPX Addresses 1/1280000 011 Reserved 1/128….0000 111 Reserved 1/1280001 Reserved 1/16001 Reserved 1/8010 Provider-assigned unicast 1/8011 Reserved 1/8100 Reserved for geographic 1/8101 Reserved 1/8110 Reserved 1/81110 Reserved 1/161111 0 Reserved 1/321111 10 Reserved 1/641111 110 Reserved 1/1281111 1110 Available for local use 1/2561111 1111 Multicast 1/256

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