IPv6 Internet Protocol Version 6

Information management 2 Groep T Leuven – Information department 2/24 Internet Protocol Version 6 (IPv6) IPv6 solutions to IPv4 disadvantages IPv6 addressing IPv6 header DNS support for IPv6 Core protocols of IPv6 IPv6 Neighbor Discovery Differences between IPv4 and IPv6

Information management 3 Groep T Leuven – Information department 3/24 Disadvantages of IPv4 Limited address space Flat routing infrastructure Configuration Security Quality of service (QoS) Mobility

Information management 4 Groep T Leuven – Information department 4/24 IPv6 Solutions to IPv4 Disadvantages Huge address space Hierarchical routing infrastructure Automatic configuration Built-in security Better support for QoS Built-in mobility

Information management 5 Groep T Leuven – Information department 5/24 Larger Address Space ~=~= ~=~= ~=~= ~=~= IPv4 32 bits or 4 bytes long 4,200,000,000 possible addressable nodes IPv6 128 bits or 16 bytes: four times the bits of IPv4 3.4 * possible addressable nodes 340,282,366,920,938,463,374,607,432,768,211,456 5 * addresses per person

Information management 6 Groep T Leuven – Information department 6/24 IPv6 Adressing 6.5 Billion people on earth Typical braincell has ~100 Billion cells (your count may vary) IPv6 addresses for every human brain cell on the planet IPv6 addresses per person

Information management 7 Groep T Leuven – Information department 7/24 Larger Address Space Enables Address Aggregation Aggregation of prefixes announced in the global routing table Efficient and scalable routing Improved bandwidth and functionality for user traffic

Information management 8 Groep T Leuven – Information department 8/24 The IPv6 Address Space 128-bit address space 128 bits were chosen to allow multiple levels of hierarchy and flexibility in designing hierarchical addressing and routing Global unicast and anycast addresses are defined by a global routing prefix, a subnet ID, and an interface ID

Information management 9 Groep T Leuven – Information department 9/24 IPv6 Address Representation x:x:x:x:x:x:x:x, where x is a 16-bit hexadecimal field Leading zeros in a field are optional: –2031:0:130F:0:0:9C0:876A:130B Successive fields of 0 can be represented as ::, but only once per address. Examples: 2031:0000:130F:0000:0000:09C0:876A:130B 2031:0:130f::9c0:876a:130b FF01:0:0:0:0:0:0:1 >>> FF01::1 0:0:0:0:0:0:0:1 >>> ::1 0:0:0:0:0:0:0:0 >>> ::

Information management 10 Groep T Leuven – Information department 10/24 Compressing Zeros Some IPv6 addresses contain long sequences of zeros A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::” (double-colon) Examples: –FE80:0:0:0:2AA:FF:FE5F:47D1 becomes FE80::2AA:FF:FE5F:47D1 –FEC0:0:0:41CD:2AA:FF:FE5F:47D1 becomes FEC0::41CD:2AA:FF:FE5F:47D1 –FF02:0:0:0:0:0:0:1 (a multicast address) becomes FF02::1

Information management 11 Groep T Leuven – Information department 11/24 IPv6 Prefixes Prefix is the part of the address where the bits have fixed values or are the bits of a route or subnet identifier IPv6 subnets or routes always uses address/prefix-length notation –CIDR notation Examples: –3FFE:FFFF:2A:41CD::/64 is a subnet identifier –3FFE:FFFF:2A::/48 is a route –FF::/8 is an address range

Information management 12 Groep T Leuven – Information department 12/24 Types of IPv6 Addresses Unicast –Address of a single interface –One-to-one delivery to single interface Multicast –Address of a set of interfaces –One-to-many delivery to all interfaces in the set Anycast –Address of a set of interfaces –One-to-one-of-many delivery to a single interface in the set that is closest No more broadcast addresses

Information management 13 Groep T Leuven – Information department 13/24 Unicast IPv6 Addresses Global addresses –Used on IPv6 Internet –Equivalent to IPv4 public addresses Local-Use Addresses –Site-local addresses Equivalent to IPv4 private addresses Always begin with FEC0 –Link-local addresses Equivalent to APIPA addresses Always begin with FE80 Link Local Site LocalGlobal

Information management 14 Groep T Leuven – Information department 14/24 IPv6 Interface Identifiers Based on: –Derived from the MAC address of the network adapter to which the address is assigned –Randomly generated to provide IPv4-equivalent anonymity –Assigned during a Point-to-Point Protocol (PPP) connection –Assigned during DHCP configuration

Information management 15 Groep T Leuven – Information department 15/24 IPv6 Interface identifier EUI-64 Cisco uses the extended universal identifier (EUI)-64 format to do stateless autoconfiguration. This format expands the 48- bit MAC address to 64 bits by inserting “FFFE” into the middle 16 bits. To make sure that the chosen address is from a unique Ethernet MAC address, the universal/local (U/L bit) is set to 1 for global scope (0 for local scope) FC0F FC0F FFFE FC0F FFFE FC0F FFFE 48 bit 64 bit U0 1 = Unique 0 = Not Unique U = Mac address

Information management 16 Groep T Leuven – Information department 16/24 IPv6 Header Fragment Offset Flags Total Length Type of Service IHL PaddingOptions Destination Address Source Address Header ChecksumProtocolTime to Live Identification Version IPv4 Header Next Header Hop Limit Flow Label Traffic Class Destination Address Source Address Payload Length Version IPv6 Header Field’s Name Kept from IPv4 to IPv6 Fields Not Kept in IPv6 Name and Position Changed in IPv6 New Field in IPv6 Legend

Information management 17 Groep T Leuven – Information department 17/24 IPv6 Extension Header types Routing Header Fragmentation Header Hop-by-Hop Options Header Destinations Options Header Authentication Header Encrypted Security Payload Header Ethernet header IPv6 header Routing header Frag header Auth header ESP header TCP header Application data

Information management 18 Groep T Leuven – Information department 18/24 DNS Support for IPv6 AAAA resource records for name-to-address resolutions PRT resource records in the IP6.ARPA reverse domain for address-to-name resolutions

Information management 19 Groep T Leuven – Information department 19/24 Core Protocols of IPv6 IPv6 –Replacement for IPv4 ICMPv6 –Replacement for ICMP for IPv4 Neighbor Discovery –Replacement for ARP, Redirect, and Router Discovery for IPv4 Multicast Listener Discovery –Replacement for IGMPv2 for IPv4

Information management 20 Groep T Leuven – Information department 20/24 IPv6 Neighbor Discovery Messages –Neighbor Solicitation –Neighbor Advertisement –Router Solicitation –Router Advertisement –Redirect Processes –Address resolution –Duplicate address detection –Router discovery –Redirect –Neighbor unreachability detection

Information management 21 Groep T Leuven – Information department 21/24 Stateless Autoconfiguration A router sends network information to all the nodes on the local link. A host can autoconfigure itself by appending its IPv6 interface identifier (64-bit format) to the local link prefix (64 bits). The result is a full 128-bit address that is usable and guaranteed to be globally unique.

Information management 22 Groep T Leuven – Information department 22/24 A Standard Stateless Autoconfiguration Stage 1: The PC sends a router solicitation to request a prefix for stateless autoconfiguration.

Information management 23 Groep T Leuven – Information department 23/24 Stage 2: The router replies with a router advertisement. A Standard Stateless Autoconfiguration (Cont.)

Information management 24 Groep T Leuven – Information department 24/24 Differences Between IPv4 and IPv6 FeatureIPv4IPv6 Address length32 bits128 bits Header size20-60 bytes40 bytes IPSec supportOptionalRequired QoS supportSomeBetter FragmentationHosts and routersHosts only Checksum in headerYesNo Options in headerYesNo Link-layer address resolutionARP (broadcast)Multicast Neighbor Discovery Messages Multicast membershipIGMPMulticast Listener Discovery (MLD) Router DiscoveryOptionalRequired Uses broadcasts?YesNo ConfigurationManual, DHCPAutomatic, DHCP DNS name queriesUses A recordsUses AAAA records DNS reverse queriesUses IN-ADDR.ARPA Uses IP6.ARPA