KOM 15032: Arsitektur Jaringan

TerkiniBab 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 * 109 (Billion)

IPv6: 2^128 = 3.4 * 1038 (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 450.000 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

00101010000100100011010001011100000000000000000000000000000000000000000001111000000010011010101100001100000011011110000011110000

IPv6 Address Notation

2A12:345C:0:0:78:9AB:C0D:E0F0

IPv6 Address Notation (cont.)

2A12:345C:0:0:78:9AB:C0D:E0F0

00101010000100100011010001011100000000000000000000000000000000000000000001111000000010011010101100001100000011011110000011110000

Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.)

2A12:345C:0:0:78:9AB:C0D:E0F0

00101010000100100011010001011100000000000000000000000000000000000000000001111000000010011010101100001100000011011110000011110000

Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.)

2A12:345C:0:0:78:9AB:C0D:E0F0

00101010000100100011010001011100000000000000000000000000000000000000000001111000000010011010101100001100000011011110000011110000

Eight blocks of 16 bits in hexadecimal separated by colons (:)

IPv6 Address Notation (cont.)

2A12:345C:0:0:78:9AB:C0D:E0F0

00101010000100100011010001011100000000000000000000000000000000000000000001111000000010011010101100001100000011011110000011110000

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

<prefix>/<prefix-length>

1234:5678::/481234:5678:9ABC: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 ID Top-level aggregation identifier

RES Reserved for future use

NLA ID Next-level aggregation identifier

SLA ID Site-level aggregation identifier

Interface ID Interface 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 00-12-34-56-78-9a

Interface ID 212:34ff:fe56:789a

Link-local Address Format

KAME style

fe80:<Interface-ID>%<ifname>

fe80::212:34ff:fe56:789a%fxp0

fe80::<Interface-ID>

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