IPv6 is the successor to the current IPv4 protocol and is necessary because we are running out of IPv4 addresses. While IPv6 has been defined for over 15 years, adoption has been slow because NAT allows the continued use of IPv4 by making addresses shared. However, NAT causes problems for applications and means devices cannot directly communicate. Major networks are now adopting IPv6, so transition is needed to maintain connectivity. Options for transition include running dual stack IPv4 and IPv6 networks, using IPv6-only with NAT64 for IPv4 connectivity, or adopting dual stack for servers and NAT64 for IPv4 clients.

1. IPv6:
What, Why and How?
Gihan Dias
University of Moratuwa
World IPv6 Launch - 6/6/2012

2. What is an IP Address?

3. An IP address is a number used to
identify a computer on a network
Every computer on the net must have an
IP address
phone
TV
refrigerator
light

4. How many IP addresses
do we have?
The current version of IP (IPv4) has about
4 billion addresses
and about the same number of devices
So we are running out of IPv4 addresses

5. The Asia Pacific Network Information Centre
(APNIC) has reached the last block of
Internet Protocol version 4 (IPv4) addresses
in its available pool.
The remaining IPv4 space will be ‘rationed’
to network operators to be used as essential
connectivity with next-generation IPv6
addresses.
“From this day onwards, IPv6 is mandatory
for building new Internet networks and
services.” - APNIC Director General Paul Wilson

6. What do we do?

7. Use IP version 6 (IPv6)

8. IPv6
IPv6 is the successor to IPv4
Defined in 1996
over 15 years ago
uses 128-bit addresses
more than enough for any conceivable
purpose

9. IPv6 Support
IPv6 is supported by all operating
systems
Windows
Linux
OS/X, iOS
Android, etc.
Supported by all router / switch
manufacturers
Cisco, Juniper, etc.

10. but
IPv6 is hardly used today

11. Why?

12. Why is IPv6 not in use?
Not supported by some low-end devices
Limitations in early support by Windows
XP, etc.
Some applications don't support it
The Main Reason?
I don't need to use it

13. Why Don't we Need IPv6?

14. NAT

15. What is NAT?
Network Address Translation
Computers in an organisation use private
IP addresses
e.g. beginning with 192.168.
A NAT translates these addresses into
one or more public IP addresses
100's of computers can use one public IP
address

16. NAT: Network Address Translation
rest of local network
Internet (e.g., home network)
10.0.0/24 10.0.0.1
10.0.0.4
10.0.0.2
138.76.29.7
10.0.0.3
All datagrams leaving local Datagrams with source or
destination in this network
ave same single source NAT IP address: 138.76.29.7,
different source port numbers have 10.0.0/24 address for
source, destination (as usual)

17. Problems with NAT
Breaks the core Internet concept of
"one device, one address"
Devices can't talk directly to one-another
No inbound services
Some applications won’t work
e.g. IPsec, WINS

18. Main Problem with NAT
Servers can't use NAT
they need to be accessible from outside
Need a public IP address for each server
or some kind of address sharing
So if you have lots of servers, you need
lots of IP addresses
where do you get them from?

19. Advantage of NAT
Devices can't be reached from outside
Better security
is it?
It is quite easy for hackers to get to NATTed
machines via e-mail, web, etc.
NAT provides only marginal security

20. Current Situation
No need for panic
ISPs in Sri Lanka have enough IPv4s to
last for another couple of years

21. Now
Only one or two addresses per customer
so what if you want to run five servers?
ADSL customers will have to share IPs
3G customers don't get a public IP even now

22. from Today
Major providers (Google, Facebook, etc.)
will be on IPv6.
and many others
major local sites to follow soon
Huge numbers of clients – starting from
China and Japan) will be on IPv6
They need to access you
You need to access them

23. What are my Options?

24. Do Nothing
Use NAT for my clients
need one public IP
Use available public IPv4 for servers
may need to share addresses
beg your ISP for addresses
buy addresses

25. Do Nothing (cont.)
Need gateway to access v6 Internet
who provides it?
Need gateway for v6 clients to access
your servers
who provides it?
No direct device-to-device communication
may miss out on new services

26. Dual Stack
Run both v4 and v6 on your computers
Management is complicated
Performance and Security issues

27. v6-only Network
Need gateway to connect to v4 world
NAT64
Servers still need public IPv4 addresses
May be best solution for a new network
some applications may still not work

28. Dual Stack Servers and v4
Clients
Only a small number of servers, so easier
to manage dual stack
Your services are available to the entire
Internet
Clients go through NAT64
still can't use device-to-device services

29. Summary
IPv6 is here
Launched today
won't go away
Can't ignore it
maybe you can ignore it for a year
But will need to transition

30. Gihan Dias
gihan@uom.lk