1. Unit 1: Introduction. From IPv4 to IPv6
Internet Evolution
The need for high-speed, high-capacity networks with quality-of-service (QoS) guarantees
Protocol and implementation: a simple example
IPv6
Goals
Main Features
Main Header
Address Formats and Notation
Extension Header
Transition from IPv4 to IPv6
Dual stack
Header translation
Tunneling
Configured
Automatic

2. Introduction: Internet Evolution
Year
Event
1966
APRA packet-switching experimentation
1969
First ARPANET nodes operational
1972
Distributed invented
1973
First non-U.S. computer linked to ARPANET
1975
ARPAET transitioned to Defense Communications Agency
1980
TCP/IP experimentation begins
1981
New host added every 20 days
1983
TCP/IP switchover complete
1986
NSFnet backbone created
1990
ARPANET retired
1991
Gopher introduced
WWW invented
PGP (Pretty Good Privacy) released
1992
Mosaic introduced
1995
Internet backbone privatized
1996
OC-3 (155 Mbps) backbone built
1998
Number of registered domain names exceeds 2 million
2000
Number of indexable web pages exceeds 1 billion

4. Increased speed and efficiency of networks and the Internet
The need for high-speed, high-capacity networks with quality-of-service (QoS) guarantees
Availability of Web-based applications that are palatable to the end user
Increased speed and efficiency of networks and the Internet
Increase in traffic volume generated by users
Emergence of High-Speed LANs
Corporate Wide Area Networking needs: from centralized to network-centric
Digital electronics: DVD, digital cameras etc.

5. QoS on the Internet

6. To provide QoS
Two emerging changes to the internet architecture
ISA (Integrated Services Architecture)
Differentiating Services (DS)
Involve upgrading router hardware and involve a number of new protocols
IPv6: it provides features that are useful to ISA and DS
RSVP: The Resource ReServation Protocol – Key element of ISA
RTP: The Real-Time Transport Protocol
Multicast routing protocols

7. Network Protocols =
agreed-upon ways in which computers exchange information
Syntax: structure or format of the data
Semantics: meanings
Timing: when data should be sent and how fast it can be sent.
A simple example protocol and its implementation: SLIP

8. SLIP (Serial Line IP): RFC 1055 Character-oriented END IP-packet END …
Character stuffing
The following C language function sends SLIP packets.
They depend on two functions, send_char() and recv_char(), which send
and receive a single character over the serial line.
/* SLIP special character codes */
#define END /* indicates end of packet */
#define ESC /* indicates byte stuffing */
#define ESC_END /* ESC ESC_END means END data byte */
#define ESC_ESC /* ESC ESC_ESC means ESC data byte */

9. /* for each byte in the packet, send the appropriate character
* sequence */
while(len--) {
switch(*p) {
/* if it's the same code as an END character, we send a
* special two character code so as not to make the
* receiver think we sent an END
case END:
send_char(ESC);
send_char(ESC_END);
break;
/* if it's the same code as an ESC character,
* we send a special two character code so as not
* to make the receiver think we sent an ESC
case ESC:
send_char(ESC_ESC);
/* otherwise, we just send the character
default:
send_char(*p); }
p++;
/* tell the receiver that we're done sending the packet
send_char(END);

10. IPv6 (IPng)
(1990: IETF starts to work on a new protocol.
RFC call for proposals for discussion. Listed goals)
Goals:
1.    Support billions of hosts, even with inefficient address space allocation.
2.    Reduce the size of the routing tables.
3.    Simplify the protocol, to allow routers to process packets faster.
4.    Provide better security than current IP.
5.    Pay more attention to type of service, particularly for real-time data.
6.    Aid multicasting by allowing scopes to be specified.
7.    Make it possible for a host to roam without changing its address.
8.    Allow the protocol to evolve in the future.
9.    Permit the old and the new protocols to coexist for years.
Main Features:
·       128-bit address.
·       Simplification of header: 7 fields vs 13 in IPv4.
·       Better support for options.
·       Big advance in security: authentication and privacy.
·       More attention to type of service.

11. Figure IPv6 address
Figure Abbreviated address

12. FDEC:0:0:0:0:BBFF::/96 or FDEC::BBFF:0:0/96
Figure Abbreviated address with consecutive zeros
Figure Partial address
FDEF::BBFF/96 actually expands into FDEF:0:0:0:0:0:0:BBFF/96
= FDEF:0:0:0:0:0
FDEC:0:0:0:0:BBFF::/96 or
FDEC::BBFF:0:0/96

13. Figure 25-5
Address Structure

14. Figure 25-6 Provider-based address
Figure Address hierarchy

15. Figure 25-8 Unspecified address: as a source address only when a host does not know its own address
Figure Loopback address

16. Figure 25-10 Compatible address: IPv4 only
Figure Mapped address: Migrated to IPv6 but still want to use IPv4

17. Local Addresses
Figure Link Local Address – like private address not to be used on the Internet
Figure Site local address: private addresses for a network with several subnetworks not connected to the Internet
Figure Multicast address

18. Figure IPv6 Datagram
Figure IPv6 datagram format

19. Figure 25-17 Extension Header format

20. Hop-by-hop option header format
Figure
Hop-by-hop option header format

21. The format of options in a hop-by-hop option header
Jumbo payload

22. Extension header for routing

23. Extension header for routing (source routing)

24. Authentication Header
Fragmentation Header
In IPv6
minimum MTU = 576 bytes
only source can fragment. Use Path MTU Discovery technique to find the smallest MTU or use 576.
Authentication Header
Validate the message sender
Ensures integrity of data (data not altered.
Security parameter index  what algorithm to use
Encrypted Security Payload (ESP)

25. Transport-Mode Encryption
e.g.TCP segment or UDP datagram
Transport-Mode Encryption
Tunnel-Mode Encryption

26. Transport mode vs tunnel mode
(Usually host to host)
(Usually between security devices such as firewalls and gateways)

27. Transition from IPv4 to IPv6: Strategies
Dual-stack operation
An IPv6 nodes run both IPv6 and IPv4 and use the Version field to decide which stack should process an arriving packet.
Initially all hosts should have a dual stack before migrating completely.

28. Header Translation
When a majority of the Internet has migrated to IPv6

29. Tunneling: when IPv6 packets must travel through an IPv4 region
Tunneling (Configured)

30. Tunneling (Automatic)

31. Sending rules for an IPv6/IPv4 node
Key to abbreviations