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: VERS (4) HLEN SERVICE TYPE
TOTAL LENGTH
IDENTIFICATION
TIME TO LIVE
FLAGS
PROTOCOL
FRAGMENT OFFSET
HEADER CHECKSUM
SOURCE IP ADDRESS
DESTINATION IP ADDRESS
IP OPTIONS (IF ANY)
PADDING
DATA
• IPv6 - a set of variable-length (optional) headers:
VERS (6)
TRAFFIC CLASS
PAYLOAD LENGTH
NEXT HEADER
SOURCE IP ADDRESS
DESTINATION IP ADDRESS
FLOW LABEL
HOP LIMIT
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
HEADER HEADER 1
….
EXTENSION
HEADER N
DATA
IPv6 Extension Headers (cont)
•
Zero extension headers
Base Header
Next=TCP
TCP Segment
• One Extension header
Base Header
Next=Route
Route Header
Next=TCP
TCP Segment
• Two extension headers
Base Header
Next=Route
Route Header
Next=Auth
Auth Header
Next=TCP
TCP Segment
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
Auth Header
Next=TCP
TCP Segment
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
ESP Header
Next=TCP
Encrypted TCP Segment
ESP Trailer
Padding Pad Len Next Header
Security Parameter Index
ESP Auth Data (Var)
Sequence Number
ESP Tunnel Mode
• Encryption of entire datagram for privacy
Base Header
Next=ESP
ESP Header
Next=IP
Encrypted Datagram
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
– 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
00000000
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
0
0
8
16
netid
24
31
24
hostid
31
24
31
hostid
• Class B
0
10
8
netid
16
• Class C
0
110
8
16
netid
hostid
IPv6 Address Assignment
Binary Prefix
Type of Address
Part of Address Space
0000 0000
0000 0001
0000 001
0000 010
0000 011
….
0000 111
0001
001
010
011
100
101
110
1110
Reserved
1111 0
1111 10
1111 110
1111 1110
1111 1111
Reserved (IPv4 compatible)
Reserved
NSAP Addresses
IPX Addresses
Reserved
1/256
1/256
1/128
1/128
1/128
Reserved
Reserved
Reserved
Provider-assigned unicast
Reserved
Reserved for geographic
Reserved
Reserved
1/128
1/16
1/8
1/8
1/8
1/8
1/8
1/8
1/16
Reserved
Reserved
Reserved
Available for local use
Multicast
1/32
1/64
1/128
1/256
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
010 Provider ID Subscriber ID Subnet ID
Provider prefix
Subscriber prefix
Subnet prefix
IPv6 address
Node ID