ipv6 fundamentals chapter 3 : ipv6 addressing

IPv6 FundamentalsChapter 3: IPv6 Addressing

Rick Graziani

Cabrillo College

[email protected]

Fall 2013

2© 2013 Cisco Systems, Inc. All rights reserved. Cisco confidential.Cisco Networking Academy, US/Canada

Topics• Format of an IPv6 Address

• IPv6 Address Types

• Global Unicast IPv6 Address

• Subnetting


So we can finish, please hold questions until the end….I will be available afterward!


Why are they making me learn IPv6?


The Internet of Things, The Internet of Everything

• The Internet is more than just connecting people.

• At the very least we need IPv6 for the Internet to continue.

• So, the “killer application” for the Internet is the Internet itself.


Important moments in history…

• Monday, January 31, 2011 IANA allocated two blocks of IPv4 address space to APNIC, the RIR for the Asia Pacific region

• This triggered a global policy to allocate the remaining IANA pool of 5 /8’s equally between the five RIRs.

• So, basically…


“All of this could have all been avoided with IPv6.”


IPv4 IPv6

When do I have to go to IPv6?

• IPv4 and IPv6 will coexist for the foreseeable future.

• Dual-stack – Device running both IPv4 and IPv6.


Various transition strategies

Tunneling – IPv6 packets encapsulated inside IPv4 packets.

NAT64 – Translating between IPv4 and IPv6.

Native IPv6 – All IPv6 (our focus and the goal of every organization).


No more NAT as we know it

• IETF does not support the concept of translating a “private IPv6” address to a “public” IPv6 address.

• NAT for IPv4 breaks many things.

192.168.1.0/24RFC 1918 Private Address

Public IPv4 Address


IPv4 and IPv6

• IPv6 is more than just larger address space.

• It was a chance to make some improvements on the IP protocol.


IPv6 at a Glance • Next Header = Protocol field in IPv4.

• Indicates the data payload type (TCP, UDP, ICMPv6)

• Hop Limit = TTL (Time to Live) in IPv4. • Number of router hops before packet is discarded.

• Routers do not fragment IPv6 packets unless it is the source of the packet.

• Use of a Link-Local Address.

• ICMPv6 is more robust than ICMPv4.

• SLAAC (Stateless Address Autoconfiguration) for dynamic addressing.


Understanding the format of IPv6 Address


IPv6 Address Notation

IPv6 addresses are 128-bit addresses represented in:

Eight 16-bit segments or “hextets” (not a formal term)

Hexadecimal (non-case sensitive) between 0000 and FFFF

Separated by colons

Reading and subnetting IPv6 is easier than IPv4!

One Hex digit = 4 bits

2001:0DB8:AAAA:1111:0000:0000:0000:0100/64

2001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 010016 bits

116 bits

216 bits

316 bits

416 bits

516 bits

616 bits

716 bits

8


How many addresses does 128 bits give us? 340 undecillion addesses or … 340 trillion trillion trillion addresses or … “50 billion billion billion addresses for every person on earth” or…. “A string of soccer balls would wrap around our universe 200 billion

times!” … in other words … You won’t need to learn IPv7 for the next version of CCNA!

2001:0DB8:AAAA:1111:0000:0000:0000:0100/64

2001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 010016 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits


This isn’t the first time

• Early versions of CCNA included:•IPv4•Appletalk•IPX


Rule 1: Leading 0’s Two rules for reducing the size of written IPv6 addresses. The first rule is: Leading zeroes in any 16-bit segment do not have to

be written.

2001 : 0DB8 : 0001 : 1000 : 0000 : 0000 : 0ef0 : bc002001 : DB8 : 1 : 1000 : 0 : 0 : ef0 : bc00

2001 : 0DB8 : 010d : 000a : 00dd : c000 : e000 : 00012001 : DB8 : 10d : a : dd : c000 : e000 : 1

2001 : 0DB8 : 0000 : 0000 : 0000 : 0000 : 0000 : 0500 2001 : DB8 : 0 : 0 : 0 : 0 : 0 : 500


Rule 2: Double colon :: equals 0000…0000 The second rule can reduce this address even further:

Any single, contiguous string of one or more 16-bit segments consisting of all zeroes can be represented with a double colon.

FE80 : 0000 : 0000 : 0000 : 0000 : 0000 : 0000 : 0001

FE80 : : 1

FE80::1

Second Rule First Rule


Rule 2: Double colon :: equals 0000…0000 Only a single contiguous string of all-zero segments can be

represented with a double colon.

Both of these are correct…

FE80 : 0000 : 0000 : 0000 : 0014 : 0000 : 0000 : 0095

FE80 :: 14 : 0 : 0 : 95

OR

FE80 : 0 : 0 : 0 : 14 :: 95


Rule 2: Double colon :: equals 0000…0000 Using the double colon more than once in an IPv6 address can create

ambiguity because of the ambiguity in the number of 0’s.

FE80::14::95

FE80:0000:0000:0000:0014:0000:0000:0095

FE80:0000:0000::0014:0000:00000000:0095

FE80:0000:0014:0000:0000:0000:0000:0095


Network Prefixes IPv4, the prefix—the network portion of the address—can be identified

by a dotted decimal netmask or bitcount.

255.255.255.0 or /24

IPv6 prefixes are always identified by bitcount (prefix length).

Prefix length notation:

3ffe:1944:100:a::/64

16 32 48 64 bits


IPv6 Addresses


IPv6 Addressing

MulticastUnicast Anycast

Assigned Solicited Node

Global Unicast

UnspecifiedLoopback Embedded IPv4

Link-Local Unique Local

FF00::/8 FF02::1:FF00:0000/104

::/128::1/128

2000::/33FFF::/3

FE80::/10FEBF::/10

FC00::/7FDFF::/7

::/80


Global Unicast IPv6 Addresses


Interface IDSubnet IDGlobal Routing Prefix

Global Unicast Address (GUA)

001 Range: 2000::/3 0010 0000 0000 0000 :: to 3FFF::/3 0011 1111 1111 1111 ::

• Global unicast addresses are similar to IPv4 addresses• Routable• Unique

IANA’s allocation of IPv6 address space in 1/8th sections



Global Unicast Address (GUA)

001 Range: 2000::/3 0010 0000 0000 0000 :: to 3FFF::/3 0011 1111 1111 1111 ::

• Global unicast addresses are equivalent to IPv4 public addresses• Except under very specific circumstances, all end users

will have a global unicast address• Terminology:

• Prefix equivalent to network address• Prefix length equivalent to subnet mask in IPv4• Interface ID equivalent to host portion


Typical Global Unicast Address and Why We Love IPv6!

IPv4 Unicast Address

32 bits

Network portion Host portionSubnet portion

/?

IPv6 Global Unicast Address

128 bits

Global Routing Prefix Interface ID16-bit Fixed Subnet ID

/64

• 64-bit Interface ID = 18 quintillion (18,446,744,073,709,551,616) devices/subnet• 16-bit Subnet ID = 65,536 subnets

/48



/64 Global Unicast Addresses and the 3-1-4 rule

2001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 0100

3 + 1 = 4 (/64) : 42001:0DB8:AAAA:1111:0000:0000:0000:0100/642001:0DB8:AAAA:1111::100/64

16 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits

3 1 4

/48 /64


Subnetting IPv6 and Why Our Students Will Love IPv6

Just increment by 1 in Hexadecimal:

• 2001:0DB8:AAAA:0000::/64

• 2001:0DB8:AAAA:0001::/64

• 2001:0DB8:AAAA:0002::/64

• 2001:0DB8:AAAA:000A::/64 Valid abbreviation is to remove the 3 leading 0’s from the first shown quartet

• 2001:0DB8:AAAA:1::/64

3-1-4 Rule


Interface ID

Subnet IDGlobal Routing Prefix

Subnetting into the Interface ID

Prefix

64 bits48 bits 16bits/48 /112

2001 : 0DB8 : AAAA : 0000 : 0000 : 0000 : 0000 : 00002001 : 0DB8 : AAAA : 0000 : 0000 : 0000 : 0001 : 00002001 : 0DB8 : AAAA : 0000 : 0000 : 0000 : 0002 : 0000 thru2001 : 0DB8 : AAAA : FFFF : FFFF : FFFF : FFFE : 00002001 : 0DB8 : AAAA : FFFF : FFFF : FFFF : FFFF : 0000

Global Routing Prefix Subnet-ID Interface ID


Subnetting on a nibble boundary


/68 Prefix

60 bits48 bits 20 bits/48 /68

Subnetting on a nibble (4 bit) boundary makes it easier to list the subnets: /64, /68, /72, etc.2001:0DB8:AAAA:0000:0000::/682001:0DB8:AAAA:0000:1000::/682001:0DB8:AAAA:0000:2000::/68 through2001:0DB8:AAAA:FFFF:F000::/68

/68


Subnetting within a nibble


/70 Prefix

58 bits48 bits 22 bits/48 /70

2001:0DB8:AAAA:0000:0000::/70 00002001:0DB8:AAAA:0000:0400::/70 01002001:0DB8:AAAA:0000:0800::/70 10002001:0DB8:AAAA:0000:0C00::/70 1100

Four Bits: The two leftmost bits are part of the Subnet-ID, whereas the two rightmost bits belong to the Interface ID.

bits


1 bit Interface ID

Global Routing Prefix

Do we need the IPv6 equivalent to a /30?Debate for the need to use a /127

127-bit Prefix

79 bits48 bits 1bit/48 /127

• Beyond the scope of CCNA but may be of interest….• RFC 6164 - Using 127-Bit IPv6 Prefixes on Inter-Router Links

• Ping-Pong Issue • Neighbor Cache Exhaustion Issue

Subnet ID


Global Unicast

Configuring a Global Unicast Address

Dynamic

IPv6 Unnumbered

Stateless Autoconfigurati

onDHCPv6

Static EUI-64

Manual

IPv6 Address

CCNA or CCNP Routing


Topology


• Exactly the same as an IPv4 address only different.• No space between IPv6 address and Prefix-length.• IOS commands for IPv6 are very similar to their IPv4 counterpart.• All 0’s and all 1’s are valid IPv6 host IPv6 addresses.

No space

R1(config)#interface gigabitethernet 0/0R1(config-if)#ipv6 address 2001:db8:acad:1::1/64R1(config-if)#no shutdownR1(config-if)#exit


R1(config)#interface gigabitethernet 0/1 R1(config-if)#ipv6 address 2001:db8:acad:2::1/64R1(config-if)#no shutdownR1(config-if)#exitR1(config)#interface serial 0/0/0 R1(config-if)#ipv6 address 2001:db8:acad:3::1/64R1(config-if)#clock rate 56000R1(config-if)#no shutdown


show running-config command on router R1R1# show running-config<output omitted for brevity>interface GigabitEthernet0/0 no ip address duplex auto speed auto ipv6 address 2001:DB8:ACAD:1::1/64!


show ipv6 interface brief command on router R1R1# show ipv6 interface briefGigabitEthernet0/0 [up/up] FE80::FE99:47FF:FE75:C3E0 2001:DB8:ACAD:1::1 Global unicast address

Link-local unicast address

• Link-local address automatically created when (before) the global unicast address is.

• We will discuss link-local addresses next.


PC1: Static Global Unicast Address

2001:db8:acad:1::10

2001:db8:acad:1::1

64


PC1> ipconfigWindows IP ConfigurationEthernet adapter Local Area Connection: Connection-specific DNS Suffix . : IPv6 Address. . . . . . . . . . . : 2001:db8:acad:1::10

Link-local IPv6 Address . . . . . : fe80::50a5:8a35:a5bb:66e1%11 Default Gateway . . . . . . . . . : 2001:db8:acad:1::1

PC1: Static Global Unicast Address


PC1> ping 2001:db8:acad:1::1

Pinging 2001:db8:acad:1::1 from 2001:db8:acad:1::100 with 32 bytes of data:

Reply from 2001:db8:acad:1::1: time=1msReply from 2001:db8:acad:1::1: time=1msReply from 2001:db8:acad:1::1: time=1msReply from 2001:db8:acad:1::1: time=1ms

Ping statistics for 2001:db8:acad:1::1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 1ms, Average = 1ms

PC1>

Pinging a Global Unicast IPv6 AddressesPing uses ICMPv6 Echo Request and Echo Reply messages similar to ICMPv4.


Global Unicast

Manual

IPv6 UnnumberedIPv6

AddressStateless

Autoconfiguration

DHCPv6

Static EUI-64

Dynamic

Next Week: Configuring Dynamic IPv6 Addresses


IPv6 Addressing

MulticastUnicast Anycast

Assigned Solicited Node

Global Unicast

UnspecifiedLoopback Embedded IPv4

Link-Local Unique Local

FF00::/8 FF02::1:FF00:0000/104

::/128::1/128

2000::/33FFF::/3

FE80::/10FEBF::/10

FC00::/7FDFF::/7

::/80

Next Week: Other IPv6 Address Types


Web Site, Book, Etc.• Rick Graziani - [email protected]

• PowerPoints for CCNA, CCNP, IPv6• www.cabrillo.edu/~rgraziani• Username = cisco• Password = perlman

Shameless plug!

Quality time with my two nieces…

mailto:[email protected]

mailto:[email protected]

http://www.cabrillo.edu/~rgraziani

IPv6 FundamentalsChapter 3: IPv6 Addressing

Rick Graziani

Cabrillo College

[email protected]

Fall 2013

ipv6 fundamentals chapter 3 : ipv6 addressing

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