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

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

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

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

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.

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

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.

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. 192.168.1.1) Scope is defined in the address structure

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

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.

All of these are the same and valid 2001:db8:0000:0000:0056:abcd:0000:1234 2001:db8:0:0:56:abcd:0:1234 2001:db8::56:abcd:0:1234 2001: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

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: 192.168.0.2 becomes 0:0:0:0:0:0:192.168.0.2 or ::192.168.0.2 OR, in proper IPv6 hex ::c0a8:2

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.

Assigned Prefixes Allocation Prefix binary Prefix hex Fraction of address space Global unicast 001 2000::/3 1/8 Link-local unicast 1111 1110 10 fe80::/10 1/1024 Unique-local IPv6 address 1111 110 fc00::/7 Multicast 1111 1111 ff00::/8 1/256

Global Unicast Address

Where do the 64-bits come from? 64-bit Global Identifier (EUI-64TM) https://standards.ieee.org/develop/regauth/ 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

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!!

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 http://www.iana.org/numbers

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

Other addresses of note ::0 – the unassigned address ::1 – loopback (equiv to 127.0.0.1) 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!

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

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) c.j.lord@ieee.org http://www.blueridgetechnc.com