© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Operations Understanding IPv6 Addressing Architecture

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Representation Format: x:x:x:x:x:x:x:x, where x is a 16-bit hexadecimal field –2001:0DB8:010F:0001:0000:0000:0000:0ACD –Case-insensitive Leading zeros in a field are optional. –2001:DB8:10F:1:0:0:0:ACD Successive fields of 0 are represented as :: but only once in an address. –2001:DB8:10F:1::ACD

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Representation (Cont.) Example: Address: –2001:0DB8:0000:0000:FFFF:0000:0000:0ADC The following are good representations: –2001:db8::FFFF:0:0:ADC –2001:db8:0:0:FFFF::ADC The following is an incorrect representation: –2001:db8::FFFF::ADC

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Representation (Cont.) Further examples: FF02:0:0:0:0:0:0:1=> FF02::1 FF15:0:0:0:0:0:1:c001=> FF15::1:c001 0:0:0:0:0:0:0:1=> ::1 0:0:0:0:0:0:0:0=> ::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Representation (Cont.) Format: IPv4-compatible: –0:0:0:0:0:0: –= :: –= ::C000:0264 IPv4-mapped: –0:0:0:0:0:FFFF: –= ::FFFF:C000:0264

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Representation (Cont.) In a URL, the address is enclosed in brackets. Cumbersome for users Mostly for diagnostic purposes Use fully qualified domain names

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Address Types Unicast Multicast Anycast

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Unicast Unicast addresses are used in a one-to-one context. IPv6 unicast addresses: –Global unicast addresses –Link-local addresses –Unique local addresses –Special-purpose unicast Unspecified Loopback IPv4-compatible IPv4-mapped

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Interface ID Link-Local Addresses Link-local addresses: Have a scope limited to the link Are automatically configured with the interface ID 128 Bits FE80::/10 10 Bits 64 Bits 0

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Bits Interface Identifiers Interface ID 128 Bits Used to identify interfaces on a link Must be unique on that link Can be globally unique Unicast addresses may have a 64-bit interface ID. Except for unicast addresses that start with binary 000 Interface ID constructed in modified EUI-64 format

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Interface ID Subnet ID Global Unicast Addresses Global unicast addresses are addresses for generic use of IPv n-m Bits ProviderSiteInterface n Bitsm Bits Global Routing Prefix

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Interface ID Global ID Unique Local Unicast Addresses Unique local unicast addresses are addresses for local use only. FD00::/8 64 Bits PrefixLocally GeneratedInterface 8 Bits40 Bits

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Unspecified and Loopback Addresses Unspecified address: 0:0:0:0:0:0:0:0 Used as a placeholder when no address is available (initial DHCP request, DAD) Loopback address: 0:0:0:0:0:0:0:1 Same as in IPv4 Identifies self

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv4-Compatible Addresses An IPv4-compatible address refers to an IPv4 or IPv6 node that supports automatic tunneling. 0:0:0:0:0:0: = :: = ::C000:0264 0IPv4 Address 32 Bits96 Bits

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv4 Address IPv4-Mapped Addresses IPv4-mapped addresses are used to represent the addresses of IPv4 nodes as IPv6 addresses. 32 Bits80 Bits 0:0:0:0:0:FFFF: = ::FFFF: = ::FFFF:C000:0246 FFFF 16 bits

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Group ID Multicast Addresses Multicast is used in the context of one-to-many. A multicast scope is new in IPv Bits Flags 8 Bits ScopeFF Flags =4 Bits = 0, R, P, T Scope = 1 = interface-local 2 = link-local 3 = subnet-local 4 = admin-local 5 = site-local 8 = organization E = global 112 Bits

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Assigned Addresses FF0X:: is reserved (X = 0..F). Inside this range, the following are assigned: MeaningScope FF02::1 All nodes Link-local FF02::2 All routers Link-local FF02::9 All RIP routers Link-local FF02::1:FFXX:XXXX Solicited-node Link-local FF05::101 All NTP servers Site-local

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Assigned Addresses (Cont.) FF0X:: is reserved (X = 0..F). Inside this range, the following are assigned: MeaningScope FF0X::103RwhodAny scope FF0X::102SGI-DogfightAny scope FF0X::127Cisco-rp-announceAny scope FF0X::128Cisco-rp-discoveryAny scope FF05::1:3All-DHCP serversSite-local

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Anycast Addresses Anycast: Used in the context of one-to-nearest Assigned to more than one interface Allocated from the unicast address space Interface IDPrefix 128-n Bitsn Bits

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Addressing: Anycast Addresses Delivered to Nearest BGP Announce / IP Packet S: Sender D: BGP Announce / Sender IPv4 anycast example

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Anycast Addresses: LAN Nearest anycast address is whichever host is put into NodeQQ neighbor cache first. 2001:db8::20 NodeA 2001:db8::20 NodeB 2001:db8::20 NodeC 2001:db8::30 NodeQQ

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Required Host Addresses An IPv6 host interface requires the following IPv6 addresses for proper operation: A link-local address Loopback address All-nodes multicast address Any additional unicast and anycast addresses configured (automatically or manually) Solicited-node multicast address for each of its unicast and anycast addresses Multicast addresses of all other groups to which the host belongs

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Required Router Addresses An IPv6 router interface requires the following IPv6 addresses for proper operation: All the required host addresses All router multicast addresses Subnet-router anycast addresses for all interfaces for which it is configured to act as a router Other unicast or anycast configured addresses

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Addressing Architecture Binary Prefix IPv6 Notation Unspecified 00 … 0 (128 bits)::/128 Loopback 00 … 1 (128 bits)::1/128 Multicast 1111 FF00::/8 Link-local unicast FE80::/10 Unique local unicast FC00::/7 Global unicast Everything else

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Addressing Architecture (Cont.) This graph shows the IANA assignments of IPv6 addresses. X axis = full address space. Y axis = 0 or 1 if space is allocated. 1 does not mean that space is used, only reserved by IANA. 2000::/3 Space

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v db80000 Privacy Interface ID Support for randomly generated interface identifier 1129d0c1a08338d0 Randomly Created Interface Identifier

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IETF Prefix Allocation to IANA IPv6 PrefixAllocationReferenceNote ::/8Reserved by IETF [RFC3513] [1] [5] 0100::/8 Reserved by IETF [RFC3513] 0200::/7 Reserved by IETF [RFC4048] [2] 0400::/6 Reserved by IETF [RFC3513] 0800::/5 Reserved by IETF [RFC3513] 1000::/4 Reserved by IETF [RFC3513] 2000::/3 Global Unicast [RFC3513] [3] 4000::/3 Reserved by IETF [RFC3513] 6000::/3 Reserved by IETF [RFC3513] F800::/6 Reserved by IETF [RFC3513] FC00::/7 Unique Local Unicast [RFC4193] FE00::/9 Reserved by IETF [RFC3513] FE80::/10 Link Local Unicast [RFC3513] FEC0::/10 Reserved by IETF [RFC3879] [4] FF00::/8 Multicast [RFC3513] Describe the features and benefits of IPv6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary IPv6 addresses are 128 bits long, represented by a sequence of eight 16-bit hexadecimal fields separated by colons. IPv6 addresses are unicast, anycast, or multicast. Broadcast addresses are not supported in IPv6. Each of the three IPv6 address types has specific rules regarding its construction and use. Every IPv6 host and router has a set of addresses that must be configured on it to enable proper operation.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v