KOM 15032: Arsitektur Jaringan Terkini Bab 2. Pengalamatan IPv6

Course Goal  Memahami konsep dasar pengalamatan IPv6  Mengerti konsep transisi IPv4 ke IPv6

IP Addressing  How many IP address?  IPv4: 2^32 = 4.3 * 10 9 (Billion)  IPv6: 2^128 = 3.4 * (Undecillion)  When was IP address standarized?  IPv4 in 1981 (RFC 791)  IPv6 in 1995 (RFC 1883) refined in 1998 (RFC 2460) o As early as 1990, IETF started to work on IPng, solving IPv4 address shortage issue o IETF initiated the standard in 1994 o Why not IPv5?

Major Goal of IPv6  Support billion of hosts  Reduce the size of the routing table  Simplify the protocol  Provide better security (authentication & privacy)  Pay more attention in QoS  High-bandwidth multimedia and fault tolerance applications (multicast)  Allowing a host to roam without changing its address  Allow the protocol to evolve in future  Permit old and new protocols to coexist for years

Do We Need Larger IP Address Space?

What is the Problem with IPv4?  Rapid increase of the size of routing tables  More than entries in the Internet  It was predicted that IPv4 will exhaust by 2008  Theoritical limit  4 billion devices  Practical limit  250 million devices

How to Reduce IPv4 Address Depletion  Classless Inter Domain Routing (CIDR)  Network Address Translation (NAT)

CIDR  Advantages:  IP addressing scheme that replaces the older system based on classes A, B, and C. A single IP address can be used to designate many unique IP addresses  CIDR can reduce the number of routing table entries  Disadvantages:  Greater complexity  Many unused IP address

NAT  Assign private addresses to the internal systems  Router translate the addresses

NAT (cont.)  Popular on Dial-up, SOHO, and VPN  Save IPv4 address from exhausted  Lost of the end-to-end model  Asymmetric identifier

NAT Drawbacks  NAT breaks end-to-end communication  Routers monitors the communication  Routers changes the data  NAT breaks bi-directional communication  Hosts with global address can’t initiate the communication to the hosts with private address

Why 128 bit then?  Room for many levels of structured hierarchy and routing aggegation  Easier address management and delegation than IPv4  Easy address auto-comfiguration  Ability to deploy end-to-end IPsec

What’s Good About IPv6  Larger address space  128 bit  3.4 * 10^38  Re-design to solve the current problem such as:  Efficient and hierarchial addressing and routing  Security  Auto-configuration  Plug & play  Better support for QoS  Extensibility

Is IPv6 really good?  IPv6 can’t easily solve (same as IPv4)  Security  Multicast  Mobile  QoS

IPv6 Addressing A 128 bit value that representing an interface on the network

IPv6 Address Notation 2A12:345C:0:0:78:9AB:C0D:E0F0

IPv6 Address Notation (cont.) 2A12:345C:0:0:78:9AB:C0D:E0F Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.) 2A12:345C:0:0:78:9AB:C0D:E0F Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.) 2A12:345C:0:0:78:9AB:C0D:E0F Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.) 2A12:345C:0:0:78:9AB:C0D:E0F Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.)  Blocks of 0 may be shortened with double colon (::), but only one :: is allowed 1234:5678:90AB::5678:0:CDEF 1234:5678:90AB:0:0:5678::CDEF 1234:5678:90AB::5678::CDEF

IPv6 Address Space Notation / 1234:5678::/ :5678:9ABC:DEF::/64

IPv6 Address Type  Unicast  Single interface  Multicast  Set of interfaces  Packets delivered to all interfaces  Anycast  Set of interfaces  Packets delivered to one (the nearest) interface

Address Type Identification

Global Aggregatable Unicast Address Format  TLA IDTop-level aggregation identifier  RESReserved for future use  NLA IDNext-level aggregation identifier  SLA ID Site-level aggregation identifier  Interface IDInterface identifier

An Interface’s Unicast Address A link’s prefix length is always 64 bit

Allocationg IPv6 Address Space 2001:df0:ba::/48 16 bits for link’s network prefixes = 65k

Interface Identifier  Interface ID  manual or automatic  Automatic  modified EUI-64 of MAC address  Complement 2nd LSB of 1st byte  Insert 0xfffe between 3rd and 4th bytes  MAC  a  Interface ID  212:34ff:fe56:789a

Link-local Address Format  KAME style fe80: % fe80::212:34ff:fe56:789a%fxp0 fe80::

Multicast Address Format Flags: LSB = 0 well-known multicast address LSB = 1 temporary/transient multicast address Scope: 1 interface-link scope 2 link-local scope 5 site-local scope 8 organization-local scope E global scope

Multicast Address Example  ff02::2  Well-known address, link-local scope  Ff18::100  Temporary address, organization-local scope

A Node’s Address  Loopback Address  Link-local Address for each interface  Additional Unicast and Anycast Addresses  All-Nodes Multicast Addresses (ff02::1)  Solicited-Node Multicast Addresses  Multicast Addresses of groups it joined

A Router’s Address  A Node’s Address  Subnet-Router Anycast Addresses  All other Anycast Addresses  All-Router Multicast Addresses (ff02::2)

IPv4 vs IPv6 Header

What are Missing from IPv4 in IPv6?  Fragmentation/Reassembly  IPv6 doesn’t allow for freagmentation/reassembly  Header checksum  Transport layer and data link layer have handle it  Options  Fixed-length 40 byte IP header  No longer a part of standard IP header  But, there is next header

Transition from IPv4 to IPv6  Generally, there are 3 approaches for transitioning to IPv6: 1. Dual-stack (running both IPv4 and IPv6 on the same device)  To allow IPv4 and IPv6 to co-exist in the same devices and networks 2. Tunneling (transporting IPv6 traffic through an IPv4 network transparently)  To avoid dependencies when upgrading hosts, routers, or regions 3. Translation (converting IPv6 traffic to IPv4 traffic for transport and vice versa)  To allow IPv6-only devices to communicate with IPv4-only devices

Dual-Stack Approach  Dual-stack node means:  Both IPv4 and IPv6 stacks enabled  Applications can talk to both  Choice of the IP version is based on name lookup and application preference

Dual-Stack Approach (cont.)  A system running dual-stack, an application with IPv4 and IPv6 enabled will:  Ask the DNS for an IPv6 address (AAAA record)  If that exists, IPv6 transport will be used  If it doesn’t exist, it will then ask the DNS for an IPv4 address (A record) and use IPv4 transport instead

Tunneling Approach  Manually configured  Manual tunnel (RFC 4213)  GRE (RFC 2473)  Semi-automated  Tunnel broker  Automatic  6to4 (RFC 3056)  6rd  ISATAP (RFC 4214)  TEREDO (RFC 4380)

Translation Approach  Techniques:  NAT-PT  require Application Layer Gateway (ALG) functionality that converts Domain Name System (DNS) mappings between protocols (not really in use, since NAT64 came)  NAT64  combined with DNS64