This document provides an overview of IPv6 and how it addresses limitations in IPv4. IPv6 features a 128-bit address size allowing for more addresses compared to IPv4's 32-bit addresses. This growth is needed as IPv4 addresses are being depleted. IPv6 also supports mobility, security features like IPsec, and multicast and anycast addressing. While IPv4 uses Network Address Translation to work around its limited address space, IPv6 removes this need through its expanded addressing.

1. IPv6 Mechanism
SHIVAM SINGH
(M.TECH. CYBER SECURITY)

2. Contents
IPv6
Why IPv6 ?
IPv6 Addresses
 Unicast
 Multicast
 Anycast
IPv4
NAT
Why Not IPv4 ?
Difference between IPv4 and IPv6

3. IPv6
Next development version of Internet Protocol
Address size is 128 bits
IPv6 address representation:
 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
 Each x is a 4bit Hexadecimal Digit
 IPv6 addresses range from 0000:0000:0000:0000:0000:0000:0000:0000 to
ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff.

4. What’s Good about IPv6 ?
Bigger Address Space
 128 bits for addressing
 No NATs are needed
 Allows full IP connectivity
 For Computers, Mobile devices
Mobility
 Facility for mobile devices
 Allows roaming between different networks
…

5. Built-in security
 Includes IPsec
 Authentication
 Encryption
 Compression

6. Types of addresses
Unicast
 Communicate specified 1 computer
Multicast
 Communicate group of computers
Anycast
 Send group address that can receive multiple computers, but receive 1 computer
s d
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a) Unicast b) Multicast c) Anycast

7. IPv6 Unicast
To transmit data from one point to another.
Multiple users might request
 Same data
 From the same server
 At the same time
 Duplicate data streams are transmitted one to each user
Scope may be Global or Local
 Global for worldwide communication
 Local for communication within a site

8. IPv6 multicast
Ability to send a single packet to multiple destinations
No broadcast
 Ability to send a packet to all hosts on the attached link
 same effect can be achieved by sending a packet to the link-local all hosts multicast
group
Applications
 Telephony and video conference
 Database simultaneous update
 Parallel computing
 Real time news

9. Uses Anycast address
 Identifies a set of nodes
 Packet will reach only one out of many (usually, topologically closest one)
 Anycast address can be assigned to routers only
 Anycast address cannot be used as a source
Anycast

10. IPv4
Forth revision of development of Internet Protocol(IP)
Most widely used protocol at present
Connection-less protocol used on packet-switched Link Layer networks
A system of addresses
 To identify devices
 32 bits
 232 combinations
 Nearly 4.3 billion
Not enough and more addresses are needed

11. Network Address Translation(NAT)
Allows to maintain public IP addresses and private IP addresses
separately
Also used in server load balancing
This operates in side the router
Maintains an address pool
First the destination is checked
The address is translated
The network address information in the datagram is modified

12. When a client on the internal network contacts a machine on the
Internet, it sends out IP packets destined for that machine.
When the packets pass through the NAT gateway they will be modified
so that they appear to be coming from the NAT gateway itself.
Neither the internal machine nor the Internet host is aware of these
translation steps.
When the Internet host replies to the internal machine's packets, they
will be addressed to the NAT gateway's external IP (198.51.100.1) at the
translation port (53136).
How NAT Work ?

13. Problems of IPv4
1.Insuffieciency
- Only four bytes
◦ Maximum nodes ~ 4.3 billion
◦ Much less than the human population (6.799 billion)
- Not enough for growing number of users
- Will be exhausted in near future
2.Increasing routing information
- Rapid growth of routing tables in backbones
3. Increasing the number of Network Address Translation (NAT)
- Breaking the Internet architecture

14. 4.Security issues
- Number of ways to encrypt IPv4 traffic
◦ Example: IPSec
- No real standard encryption method
5.Real-time delivery of multimedia content and necessary bandwidth
allocation
◦ Quality of Service (QoS)
◦ Different interpretations
◦ QoS compliant devices are not compatible one another

15. IPv4 vs IPv6
Header is simplified, has fixed size (40bytes); IPv6 introduces the
concept of (optional) extension headers for fragmentation, header
options etc.
Header checksum removed; this function is already covered by layer 2
protocols (e.g. Ethernet and Frame Relay). Anyway, the IPv4 checksum
does not provide Forward Error Correction (possibility to correct errors
based on the checksum) thus it is basically useless (routers have to drop
errored packet anyway).
Bigger addresses (128 bits as opposed to 32 bits in IPv4).