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
…
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
g
s
g
g
a
s
a
a
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).