ipv6 fundamentals chapter 4: ipv6 address types

IPv6 FundamentalsChapter 4: IPv6 Address

TypesRick Graziani

Cabrillo College

[email protected]

Fall 2013

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

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


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


Global Unicast

Manual

IPv6 UnnumberedIPv6

AddressStateless

Autoconfiguration

DHCPv6

Static EUI-64

Dynamic

Configuring Dynamic IPv6 Addresses


IPv4 Dynamic AddressesDHCP Server


• The Router Advertisement (RA) tells hosts how it will receive IPv6 Address Information.

• Sent periodically by an IPv6 router or…

• When the router receives a Router Solicitation message from a host.

With IPv6 it begins with the Router Advertisement


Router Advertisement

Router Advertisement/Solicitation Messages

• Part of ICMPv6 (Internet Control Message Protocol for IPv6)

• Router Advertisements are sent by an “IPv6 router” – ipv6 unicast-routing command• Forwards IPv6 Packets• Can be enabled for IPv6 static and dynamic routing• Sends ICMPv6 Router Advertisements

• Routers can be configured with IPv6 addresses without being an IPv6 router

DHCPv6 Server

R1(config)# ipv6 unicast-routing


SLAAC (Stateless Address Autoconfiguration)

DHCPv6 Server


Option 1 (Default on Cisco routers)“I’m everything you need (Prefix, Prefix-length, Default Gateway)”

Option 2 (Discussed in CCNA Switching) “Here is my information but you need to get other information such as DNS addresses from a DHCPv6 server.”

Option 3 (Discussed in CCNA Switching)“I can’t help you. Ask a DHCPv6 server for all your information.”

RA

DHCPv6

• Option 1 and 2: Stateless Address Autconfiguration – DHCPv6 Server does not maintain state of addresses

• Option 3: Stateful Address Configuration – Address received from DHCPv6 Server


Router Advertisement – Option 1

Option 1 – RA MessageTo: FF02::1 (All IPv6 devices multicast)From: FE80::1 (Link-local address)Prefix: 2001:DB8:ACAD:1:: Prefix-length: /64

RA

1

MAC: 00-03-6B-8C-E0-80

Prefix: 2001:DB8:ACAD:1:: Prefix-length: /64Default Gateway: FE80::1Global Unicast Address:2001:DB8:ACAD:1: + Interface ID

2001:DB8:ACAD:1::/64

EUI-64 Process or Random 64-bit value

2

DHCPv6 Server

3


Dynamic Interface ID

Interface IDSubnet IDGlobal Routing Prefix/48 /64 64 bits

EUI-64 Process Randomly Generated NumberSLAAC

Router Advertisement2001:DB8:ACAD:1::/64

• Windows operating systems, Windows XP and Server 2003 use EUI-64. • Windows Vista and newer; hosts create a random 64-bit Interface ID. • Linux: Mostly use random 64-bit number• Mac OSX: use EUI-64 (on my Macs)

DHCPv6 Server


EUI-64 (Extended Unique Identifier – 64)

Option 1 – RA MessageTo: FF02::1 (All-hosts multicast)From: FE80::1 (Link-local address)Prefix: 2001:DB8:ACAD:1:: Prefix-length: /64

RA

1

MAC: 00-03-6B-E9-D4-80

Prefix: 2001:DB8:ACAD:1:: Prefix-length: /64Default Gateway: FE80::1Global Unicast Address:2001:DB8:ACAD:1: + Interface ID

2001:DB8:ACAD:1::/64

EUI-64 Process or Random 64-bit value

2

DHCPv6 Server


Hexadecimal

OUI24 bits

Device Identifier24 bits

Binary

Step 1: Split the MAC address

Binary

Step 2: Insert FFFE

Binary

Step 3: Flip the U/L bit

Binary

Modified EUI-64 Interface ID in Hexadecimal Notation

1111 1111 1111 1110

1111 1111 1111 1110

02 03 6B E9 D4 80FF FE

00 03 6B E9 D4 80

0000 0000 0000 0011 0110 1011 1110 1001

1101 0100 1000 0000

1110 1001

1101 0100 1000 0000

1110 1001

1101 0100 1000 0000

0000 0000 0000 0011 0110 1011

0000 0010 0000 0011 0110 1011

EUI-64

F F F E


PC1> ipconfig

Windows IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :

IPv6 Address. . . . . . . . . . . : 2001:db8:acad:1:02-03-6b-ff-fe-e9-d4-80

Link-local IPv6 Address . . . . . : fe80::02-03-6b-ff-fe-e9-d4-80

Default Gateway . . . . . . . . . : fe80::1

PC1: Global Unicast Address

• A 64-bit Interface ID and the EUI-64 process accommodate the IEEE specification for a 64-bit MAC address.

Router Advertisement EUI-64


What about Stateful DHCPv6? (CCNA Switching)

DHCPv6• DHCPv6 is similar to

DHCPv4.

• Host operating systems “may” include the option of ignoring the Router Advertisement from the router and only use the stateful services of a DHCPv6 server.

• Note: All addresses should be checked before use with DAD (Duplicate Address Detection), similar to gratuitous ARP in IPv4.

DHCPv6 Server


Link-Local Unicast IPv6 Addresses


IPv6 Addressing



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


Interface ID/64

1111 1110 10xx xxxx

FE80::/10

Remaining 54 bits10 bits 64 bits

EUI-64, Random or Manual Configuration

Link-local Unicast

Range: FE80::/10 1111 1110 1000 0000 :: to FEBF::/10 1111 1110 1011 1111 ::


• Used to communicate with other devices on the link.• Are NOT routable off the link (network).• Only have to be unique on the link.• Are not included in the IPv6 routing table.• An IPv6 device must have at least a link-local address.• Used by:

• Hosts to communicate to the IPv6 network before it has a global unicast address.• Router’s link-local address is used by hosts as the default gateway address.• Adjacent routers to exchange routing updates

Link-local unicastLink-Local Communications


R1

G0/0

G0/1

S0/0/0

R1#show interface gigabitethernet 0/0GigabitEthernet0/0 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is fc99.4775.c3e0 (bia fc99.4775.c3e0)<Output Omitted>

R1#show ipv6 interface briefGigabitEthernet0/0 [up/up] FE80::FE99:47FF:FE75:C3E0 2001:DB8:ACAD:1::1GigabitEthernet0/1 [up/up] FE80::FE99:47FF:FE75:C3E1 2001:DB8:ACAD:2::1Serial0/0/0 [up/up] FE80::FE99:47FF:FE75:C3E0 2001:DB8:ACAD:3::1R1#

IOS uses EUI-64 to Create Link-Local Addresses

EUI-64

Serial interfaces will use a MAC address of an Ethernet interface.

FF:FE = EUI-64 (most likely)

Wait! Two Link-Locals

are the same!


PC1> ipconfig

Windows IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix .:

IPv6 Address. . . . . . . . . : 2001:db8:acad:1:3496:1c51:3f57:fe89

Link-local IPv6 Address . . . : fe80::3496:1c51:3f57:fe89

Default Gateway . . . . . . . : fe80::1

PC1: Link-Local Unicast Address

• Many operating systems will use a random 64-bit Interface IDs for GUA and Link-Local IPv6 Addresses.


R1

G0/0 FE80::1

G0/1FE80::1

S0/0/0FE80::1

Configuring Static Link-Local Addresses

R1(config)#interface gigabitethernet 0/0R1(config-if)#ipv6 address fe80::1 ? link-local Use link-local address

R1(config-if)#ipv6 address fe80::1 link-localR1(config-if)#exitR1(config)#interface gigabitethernet 0/1R1(config-if)#ipv6 address fe80::1 link-localR1(config-if)#exitR1(config)#interface serial 0/0/0R1(config-if)#ipv6 address fe80::1 link-localR1(config-if)#

Link-Local Addresses only have to be unique on the link!

Static addresses are more easily remembered and recognizable.


ipv6 enable commandRouter(config)# interface gigabitethernet 0/1Router(config-if)# ipv6 enableRouter(config-if)# endRouter# show ipv6 interface briefGigabitEthernet0/1 [up/up] FE80::20C:30FF:FE10:92E1Router#

• Link-local addresses are automatically created whenever a global unicast address is configured

• The ipv6 enable command will:• Create a link-local address when there is no global unicast address• Maintain the link-local address even when the global unicast address is

removed

Link-local unicast address only


R1# ping fe80::2Output Interface: ser 0/0/0% Invalid interface. Use full interface name without

spaces (e.g. Serial0/1)Output Interface: serial0/0/0Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to FE80::2, timeout is 2

secs:!!!!!

Must include exit-interface

G0/0 FE80::1 2001:0DB8:ACAD:2::/64

Ser 0/0/0:1

Ser 0/0/0 :2

R2R1FE80::1 FE80::2

Pinging a Link-Local Address

2001:0DB8:ACAD:1::/64


Multicast IPv6 Addresses


IPv6 MulticastIPv6 Addressing



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


Group IDFlag1111 1111

FF00::/8

8 bits 112bits

4 bits4 bits

Scope

IPv6 Multicast

• Similar to Multicast addresses for IPv4.

• Used to send a packet to a group of devices.

Two types:

1. Assigned

2. Solicited Node


Assigned Multicast Addresses

• FF02::1 – All IPv6 Devices• All IPv6 devices, including the

router, belong to this group.

• Every IPv6 device will listen and process packets to this address.


Assigned Multicast Addresses


• FF02::2 – All IPv6 Routers• All IPv6 routers belong to this group.

• Used to communicate with an IPv6 Router (ipv6 unicast routing)

FF02::2FE80::0123:456:789A:BCDE


R1# show ipv6 interface gigabitethernet 0/0FastEthernet0/0 is up, line protocol is up IPv6 is enabled, link-local address is FE80::FE99:47FF:FE75:C3E0 Global unicast address(es): 2001:DB8:ACAD:1::1, subnet is 2001:DB8:ACAD:1::/64 Joined group address(es): FF02::1 FF02::2 FF02::1:FF00:1 FF02::1:FF75:C3E0<output omitted for brevity>

All-IPv6 devices on this linkAll-IPv6 routers on this link: IPv6 routing enabled

Solicited-node multicast address for Link-local Unicast Address

Solicited-node multicast address for Global Address

Member of these Multicast Groups

• FF02 – “2” means link-local scope

• What is Solicited node?

Multicast Groups of a Router


Solicited Node Multicast Address (Introduction)

Solicited Node Multicast Address

• Used as a destination address when don’t know the unicast address.

• Typically used as the destination IPv6 address with:• Address Resolution (“IPv4 ARP”)• Duplicate Address Detection (“Gratuitous ARP”)

• Same intent as a broadcast but more efficient.

• Devices process packets with their solicited node multicast address as the destination address: IP and MAC.

PC2PC1 Destination: Solicited-node Multicast“Who ever has the IPv6 address 2001:DB8:ACAD:1::10 please send me your Ethernet MAC address”


Interface ID

FF02 0000 0000 0000 0000 0001 FF

Global Routing Prefix104 bits 24 bits

Global Unicast Address

Solicited-Node Multicast AddressCopy

Subnet ID

2001:0DB8:ACAD 0001 0000:0000:00 00:0010

00:0010

IPv6 Global Unicast Address: 2001:0DB8:ACAD:0001:0000:0000:0000:0010IPv6 Solicited Node Multicast Address: FF02::1:FF00:0010

104 bits

Solicited Node Multicast – It’s not pretty but it’s simple

The ugly The simple

The last 24 bits match.


PC2PC1 Destination: Solicited-node Multicast FF02::1:FF00:0010“Who ever has the IPv6 address 2001:DB8:ACAD:1::10 please send me your Ethernet MAC address”

I listen for several IPv6 addresses!

• All IPv6 Devices Multicast: FF02::1

• Link-Local Address: FE80::02-03-6B-FF-FE-8C-E0-80

• Global Unicast Address: 2001:DB8:ACAD:1::10

• Solicited Node Multicast Address: FF02::1:FF00:0010

Solicited Node Multicast – Used in Address Resolution

Note (beyond CCNA): Solicited Node Multicast addresses are also mapped to a special multicast MAC address: 33-33-FF-00-00-10


A Brief look at ICMPv6 (Internet Control Message Protocol for IPv6)


Internet Control Message Protocol (ICMPv6)

• Described in RFC 4443

• Much more robust than ICMP for IPv4

• Contains new functionality and improvements.

• More than just “messaging” but “how IPv6 conducts business”.

• General message similar to ICMP for IPv4

• Also uses Type and Code fields like in ICMPv4.

IPv6 Next Header Value: 58 decimal or 3A hexadecimal

IPv6 Header

Next Header58

ICMPv6 Header

ICMPv6 Message Body

IPv6 Data


Neighbor Discovery Protocol Uses ICMPv6• ICMPv6 informational messages used by Neighbor Discovery (RFC 4861):

• Router Solicitation Message• Router Advertisement Message

• Neighbor Solicitation Message• Neighbor Advertisement Message

• Redirect Message (Similar to ICMPv4)

Router-Device Messaging

Device-Device Messaging


Router Solicitations and Router AdvertisementsUsed by SLAAC (Stateless Address Autoconfiguration)

Router Advertisement MessageHere is one of three options:1. I have everything you need.2. I have mostly what you need, but you

will need to contact a DHCPv6 server for other information like a DNS address.

3. I have nothing for you. Contact a DHCPv6 serverl

FF02::1All IPv6 Devices

Router Solicitation MessageI need IPv6 address information.

FF02::2All IPv6 Routers

PC1

DHCPv6 Server

1

2


Neighbor Solicitations and Neighbor Advertisements

• Address Resolution - A device knows the IPv6 address but needs the Layer 2 MAC address.

• Unlike ARP, ICMPv6 Neighbor Solicitation/Advertisement messages are encapsulated in IPv6.

• Information is stored in the Neighbor Cache.

Neighbor Solicitation MessageWhoever has the IPv6 Address 2001:DB8:ACAD:1::10 please send me your Ethernet MAC address.

Solicited Node Multicast

Neighbor Advertisement MessageI have the IPv6 Address 2001:DB8:ACAD:1::10. Here is my Ethernet MAC address: 0021:9bd9:c644.

Unicast

PC2 PC11

2


Neighbor Cache

• Neighbor Cache – Maps IPv6 addresses with Ethernet MAC addresses

• Similar to ARP Cache for IPv4

• 5 States (2 noticeable and 3 transitory):• Reachable: Packets have recently been received providing confirmation that this device is

reachable.• Stale: A certain time period has elapsed since a packet has been received from this address.• Transitory States: INCOMPLETE, DELAY, PROBE (I will point you to more information)

PC1Neighbor CacheIPv6 Address MAC Address2001:DB8:ACAD:1::10 0021.9bd9.c644

Neighbor Cache

IPv6 - 2001:DB8:ACAD:1::10MAC - 0021.9bd9.c644


R1# show ipv6 neighborsIPv6 Address Age Link-layer Addr State InterfaceFE80::50A5:8A35:A5BB:66E1 16 0021.9bd9.c644 STALE Fa0/02001:DB8:ACAD:1::10 16 0021.9bd9.c644 STALE Fa0/0

R1# ping 2001:db8:aaaa:1::100

Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 2001:DB8:AAAA:1::100, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 msR1# show ipv6 neighborsIPv6 Address Age Link-layer Addr State InterfaceFE80::50A5:8A35:A5BB:66E1 16 0021.9bd9.c644 STALE Fa0/02001:DB8:ACAD:1::10 0 0021.9bd9.c644 REACH Fa0/0

R1#

Neighbor CacheWindows: netsh interface ipv6 show neighborLinux/MAC: ip neighbor show


What we covered…

• Why IPv6? (briefly and quickly)

• Format of an IPv6 Address

• IPv6 Address Types

• Global Unicast IPv6 Address

• Link-Local Unicast IPv6 Address

• Multicast IPv6 Addresses

• ICMPv6 – Neighbor Discovery Protocol

Teach it and use it, and it will all make sense!


My Afternoon Presentation:IPv6 in CCNA 2 – Routing Protocols

• Chapter 1: Routing Concepts

• Chapter 2: Static Routing• Chapter 3: Routing Dynamically

• Chapter 4: EIGRP• Chapter 5: Advanced EIGRP• Chapter 6: Single Area OSPF• Chapter 7: Advanced Single Area OSPF• Chapter 8: Multi-Area OSPF• Chapter 9: Access Control Lists• Chapter 10: IOS File Management


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 fundamentals chapter 4: ipv6 address types

Documents

cisco confidential

cisco systems

cisco networking academy

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ipv6 router orwhen

uscanada1 ipv6 addresses

global unicast addresses