IPv6 - Introduction
Michael Dirska
Hasso-Plattner-Institut Potsdam
Why a new protocol version?
• Beginning of 1990s:
– Help! - IPv4 address space is running out
– There are too few Class-B-Networks left
– Routing Tables are growing immensely
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IPv4 address structure (old)
• 32 Bit
• Written as 4 Bytes, decimal, "." inbetween
• Netmasks: number of relevant bits
0
Class A
/8
12.x.x.x
10
Class B
/16
141.89.x.x
110
Class C
/24
192.168.1.x
1110
Class D
Multicast
1111
Class E
(nicht belegt)
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IPv4 address structure (new)
• Classless Inter-Domain Routing (CIDR)
• RFC 1519 September 1993
• (www.cidr-report.org)
0
Unicast-Adressen /8 bis /24-Netze
10
"
110
"
1110
Multicast
1111
(nicht belegt)
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Internet-Routing
AS2500
WIDE Project
203.178.136.0/21
AS680
DFN G-WiN
Uni Potsdam
141.89.0.0/16
HU Berlin
141.20.0.0/16
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IP: Next Generation (IPng)
• Dec. 1993: RFC 1550
Request for White Papers
• lots of answers August 1994, examples:
– RFC 1669
"Market Viability as a IPng Criteria"
– RFC 1671
"IPng White Paper on Transition"
– RFC 1687
"A Large Corporate User's View of IPng"
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IPng renamed to IPv6
• Jan. 1995: RFC 1752
"The Recommendation for the IP Next Generation Protocol"
• Dec. 1995: RFC 1883
"Internet Protocol, Version 6 (IPv6) Specification"
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Decision in favour of a new
address space
• IPv6 has 128-Bit addresses (millions of
addresses per square meter of the earths
surface)
• the new version solves old problems
(fragmentation) and keeps the IP-header small
• elegant solution – technically!
• but: how do you switch from IPv4 to IPv6? Do
we switch at all? Can both protocols co-exist?
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Advantages of a new address
space
• We can learn from the mistakes:
– better address allocation (smaller routing tables)
– enough global routable addresses even for the
smallest imaginable devices
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Disadvantages of a new address
space
• all connections between Autonomous Systems
(AS) must be re-negotiated
• lots of work to setup a second infrastructure
• there is no „killer application“ in sight – so
why do we want it?
• see: D.Bernstein "IPv6-mess"
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current IPv6 specifications
• RFC 2460
"Internet Protocol, Version 6 (IPv6) Specification"
• RFC 2461
"Neighbor Discovery for IP Version 6 (IPv6)"
• RFC 2462
"IPv6 Stateless Address Autoconfiguration"
• RFC 2463
"Internet Control Message Protocol (ICMPv6)"
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IPv4 header
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| IHL |Type of Service|
Total Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Identification
|Flags|
Fragment Offset
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time to Live |
Protocol
|
Header Checksum
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Source Address
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Destination Address
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Options
|
Padding
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
from RFC 791
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IPv6 header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Traffic Class |
Flow Label
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Payload Length
| Next Header |
Hop Limit
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
+
|
|
+
Source Address
+
|
|
+
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
+
|
|
+
Destination Address
+
|
|
+
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
from RFC 2460
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IPv6 Adress-Struktur
• 128 Bit
• written as 8*16 Bit, hexadecimal
• : inbetween
2001:0DB8:0010:0000:0000:0000:0000:0001
2001:0DB8:10::1
FF02::1
FE80::192.168.111.40 = FE80::C0A8:6F28
2001:DB8::/32
::1
::FFFF:192.168.111.40
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IPv6 address structure
Allocation
----------------------------------Unassigned (see Note 1 below)
Unassigned
Reserved for NSAP Allocation
Unassigned
Unassigned
Unassigned
Global Unicast
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Unassigned
Link-Local Unicast Addresses
Site-Local Unicast Addresses
Multicast Addresses
Prefix
(binary)
-------0000 0000
0000 0001
0000 001
0000 01
0000 1
0001
001
010
011
100
101
110
1110
1111 0
1111 10
1111 110
1111 1110 0
1111 1110 10
1111 1110 11
1111 1111
Fraction of
Address Space
------------1/256
1/256
1/128 [RFC1888]
1/64
1/32
1/16
1/8
[RFC2374]
1/8
1/8
1/8
1/8
1/8
1/16
1/32
1/64
1/128
1/512
1/1024
1/1024
1/256
aus RFC 3513
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global IPv6 adresses
0 3
001
IANA
23
48
64
128
Interface ID
RIR
RIR
64 bit for local configuration
(auto-configuration)
LIR
LIR
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Customer
16
weitere IPv6-Adresstypen
Link Local
0
64
FE80::/64
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Interface ID
17
Interface Identifier
IEEE 802 48 bit MAC
|0
1|1
3|3
4|
|0
5|6
1|2
7|
+----------------+----------------+----------------+
|cccccc0gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm|
+----------------+----------------+----------------+
|0
1|1
3|3
4|4
6|
|0
5|6
1|2
7|8
3|
+----------------+----------------+----------------+----------------+
|cccccc1gcccccccc|cccccccc11111111|11111110mmmmmmmm|mmmmmmmmmmmmmmmm|
+----------------+----------------+----------------+----------------+
XOR 0x0200
FF
FE
aus RFC2373
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IPv6 network
link
host
router
link
node
node
FE80::/64
link
router
node
FE80::/64
link
Interface
node
host
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host
19
Stateless Address
Autoconfiguration (RFC2462)
• is always used for link-local addresses
• can be used to configure global adresses
• Duplicate Address Detection should be
performed on the link
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Neighbor Discovery (RFC2641)
•
•
•
•
•
•
•
Duplicate Address Detection
Router Discovery
Address Autoconfiguration
Next-hop Determination
Address Resolution
Neighbor Unreachability Detection
Redirect
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Neighbor Discovery
• five message types (in ICMPv6)
–
–
–
–
–
Router Discovery
Router Solicitation
Neighbor Discovery
Neighbor Solicitation
Redirect
• Why ICMPv6? You can use AH...
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transition to IPv6
IPv6
IPv4
1996
20??
t
2020 ?
2030 ?
Es wird lange Zeit gleichzeitige IPv4- und IPv6-Konnektivität
geben müssen.
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IPv4 Netzwerk
host
node
router
IPv4 Internet
node
link
node
host
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host
24
dual stack
IPv6 Internet
host
IPv6 router
node
node
node
IPv4 Internet
node
IPv4 router
node
host
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host
node
host
25
configured tunnel
IPv6 Internet
tunnel broker
node
host
IPv6 router
node
node
node
IPv4 Internet
node
IPv4 router
IPv6-over-IPv4
tunnel
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node
host
link
host
node
host
26
Windows XP
Ethernet adapter Local Area Connection:
Connection-specific
IP Address. . . . .
Subnet Mask . . . .
IP Address. . . . .
Default Gateway . .
DNS
. .
. .
. .
. .
Suffix
. . . .
. . . .
. . . .
. . . .
.
.
.
.
.
:
:
:
:
:
141.89.224.145
255.255.255.0
fe80::208:2ff:fe5e:7afd%7
141.89.224.1
Tunnel adapter Teredo Tunneling Pseudo-Interface:
Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : fe80::5445:5245:444f%8
Default Gateway . . . . . . . . . :
Tunnel adapter 6to4 Tunneling Pseudo-Interface:
Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : 2002:8d59:e091::8d59:e091
Default Gateway . . . . . . . . . : 2002:c058:6301::c058:6301
2002:836b:213c::836b:213c
Tunnel adapter Automatic Tunneling Pseudo-Interface:
Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : fe80::5efe:141.89.224.145%2
Default Gateway . . . . . . . . . :
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