1. Get Ready for the New Internet: IPv.6
Class 3: Addressing in IPv.6
September 10, 2014 Charles J. Lord, PE President, Consultant, Trainer Blue Ridge Advanced Design and Automation

2. This Week’s Agenda
9/8 Background and Overview of IP4 / IP6 9/9 Features of IPv.4 Versus IPv.6 9/10 Addressing in IPv.6 9/11 IPv.6: Traffic and Routing 9/12 Co-existing and Adopting IPv.6 – The Challenges

3. This Week’s Agenda
9/8 Background and Overview of IP4 / IP6 9/9 Features of IPv.4 Versus IPv.6 9/10 Addressing in IPv.6 9/11 IPv.6: Traffic and Routing 9/12 Co-existing and Adopting IPv.6 – The Challenges

4. Ipv.6 Addresses Three basic types: Unicast Multicast Anycast
NOTE: Broadcast from IPv4 is no longer

5. Unicast
A Unicast address uniquely identifies an interface of an IPv6 node. A packet sent to a unicast address is delivered to the interface identified by that address.

6. Multicast
A Multicast address identifies a group of IPv6 interfaces. A packet sent to a multicast address is processed by all members of the multicast group

7. Anycast
An anycast address is assigned to multiple interfaces (usually on multiple nodes). A packet sent to an anycast address is delivered to only one of these interfaces, usually the nearest one.

8. Scope An IPv.6 address has a defined Scope
Global
Non-global (link-local)
The link-local address is similar to the dedicated local addresses in IPv4 (e.g )
Scope is defined in the address structure

9. 128 bits, 8 16-bit words
An IPv6 address is expressed as eight 16-bit numbers, written in hex. Each word is separated by a colon, thus: 2001:0db8:0000:0000:0202:b3ff:fe1e:8329
Leading zeroes can be left off: 2001:db8:0:0:202:b3ff:fe1e:8329
No more than one long string of zeroes can be replaced by a double colon: 2001:db8::202:b3ff:fe1e:8329

10. Double Colon Usage
The double colon can only be used once in an address. The reason for this is its definition: Fill the address at this point with zeroes until you have 128 bits.
What about 1201:0000:0000:1b34:0000:0000:0000:02bb
Either string of zeroes can be shortened BUT NOT BOTH. Typically you shorten the longest – if both same size, you can choose either one.

11. All of these are the same and valid
2001:db8:0000:0000:0056:abcd:0000: :db8:0:0:56:abcd:0: :db8::56:abcd:0: :db8:0:0:56:abcd::1234
So how do we do lookup tables? We always work with a fully expanded address (top line).
Address ::1 (a valid address) would always be stored as 0000:0000:0000:0000:0000:0000:0000:0001

12. IPv4 Address in IPv6
You will sometimes see a v4 address integrated into a v6 address (more on that Friday) as the last four bytes. To make this less / more confusing, this can be written in a mixed mode:
 becomes 0:0:0:0:0:0: or :: OR, in proper IPv6 hex ::c0a8:2

13. Forming an Address
All addresses have a prefix that determines the scope of the address:
Unicast (unique addresses) currently begin with the bits 001 and are assigned by a regional registry service (ARIN in NA and parts of Africa) – Except for some special values, the remaining 7/8 of the possible numbers are reserved for future use.

14. Assigned Prefixes Allocation Prefix binary Prefix hex
Fraction of address space
Global unicast
001
2000::/3
1/8
Link-local unicast
fe80::/10
1/1024
Unique-local IPv6 address
fc00::/7
Multicast
ff00::/8
1/256

15. Global Unicast Address

16. Where do the 64-bits come from?
64-bit Global Identifier (EUI-64TM)
tut/eui64.pdf
For a EUI-48 (“MAC Address”), pad to 64 bits
EUI (Extended Unique Identifier) is the official, proper term, replacing
MAC
BIA
Physical, Ethernet, etc

17. How Big is this thing?
Entities (such as your local ISP) receive a Global ID of a variable length, very similar to the Class A/B/C/D in IPv4
The header is typically expressed with a length
E.G. 20b4/24, meaning it begins with 20b4 and is unique to 24 bits from the MSB.
An ISP with a 32-bit ID assignment can then assign 32 bits of subnets – MORE NETS THAN EXIST IN ALL OF IPv4!!

18. There are always exceptions
ID 0000:0000:x:x:x:x:x:x is used for loopback and other special purposes, as well as mapping IPv4 addresses as we saw previously
There are others – you can find them at iana.org
Want your own address block? Good place to start is

19. SLAAC An interface gets a router discovery with a certain prefix
SLAAC adds the unique 64-bit identifier and reports back its new address
The lower 64 bits can also be configured to be
Random number
Assigned by DHCP
Otherwise hardcoded

20. Other addresses of note
::0 – the unassigned address
::1 – loopback (equiv to )
Special IPv4 <-> IPv6 addresses (more on Fri)
Cryptographically generated addresses (CGAs)
Anycast, Multicast
Link and Site Local
We will look at some of these tomorrow!

21. This Week’s Agenda
9/8 Background and Overview of IP4 / IP6 9/9 Features of IPv.4 Versus IPv.6 9/10 Addressing in IPv.6 9/11 IPv.6: Traffic and Routing 9/12 Co-existing and Adopting IPv.6 – The Challenges

22. Please stick around as I answer your questions!
Please give me a moment to scroll back through the chat window to find your questions
I will stay on chat as long as it takes to answer!
I am available to answer simple questions or to consult (or offer in-house training for your company)