Download IPv6

IPv6
Sirak Kaewjamnong
Computer Networks
Agenda
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IPv4’s limitations?
Protocol Features
Addressing
IPv4 V.S. IPv6 functional comparison
IPv6 Standards
Conclusion
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IPv4’s Limitations
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Two driving factors : addressing and routing
Addressing : address depletion concerns
– Internet exhaust the IPv4 address space between 2005 and
2011 [RFC1752].
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Routing : routing table explosion
– Currently ~120K entries in core router
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More factors...
– Opportunity to optimized on many years of deployment
experience
– New features needed : multimedia, security, mobile, etc..
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Key Issues
The new protocol MUST
• Support large global internetworks
• A clear way to transition IPv4 based networks
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What is IPv6?
• IPv6 is short for "Internet Protocol Version 6".
• IPv6 is the "next generation" protocol designed by
the IETF to replace the current version Internet
Protocol, IP Version 4
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History of the IPv6 Effort (1)
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1990 : IETF defined a new version of IP, generally
called IP Next Generation or IPng
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Spring 1992 : IAB proposed the OSI CLNP
(Connectionless Network Protocol). Finally rejected
by IETF and working groups
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Feb 1992: 4 proposals for IPng
– CNAT, IP Encaps, Nimrod, Simple CLNP
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History of the IPv6 Effort (2)
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March 1992: merging
– IP Encaps to IPAE (IP Address Encapsulation)
– Simple CLNP to TUBA (TCP and UDP with bigger
Address)
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Dec 1992: 3 more proposals for IPng
– PIP (P Internet Protocol), SIP (Simple IP), and TP/IX
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Fall 1993 : resolution to 3 possibilities :
– TUBA
– TP/IX => CATNIP (Common Architecture for the Next
Generation Internet Protocol)
– SIP+IP encaps+PIP=> SIPP (Simple Internet Protocol
Plus)
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Jul 1994 : SIPP was chosen, known as IPv6
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IPV6 Key Advantages
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128 bit fix length IP address
Real time support
Self-configuration of workstations or auto
configuration
Security features
Support mobile workstations
Protocol remains the same principle
IPv4 compatibility
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IPV6 Address Representation
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Hexadecimal values of the eight 16-bit pieces
x:x:x:x:x:x:x:x
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Example
FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
1080:0:0:0:8:800:200C:417A
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Compressed form: "::" indicates multiple groups of
16-bits of zeros.
1080:0:0:0:8:800:200C:417A
FF01:0:0:0:0:0:0:101
0:0:0:0:0:0:0:1
0:0:0:0:0:0:0:0
1080::8:800:200C:417A
FF01::101
::1
::
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IPV6 Address Representation(cont)
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Mixed environment of IPv4 and IPv6 address
IPv4-compatible IPv6 address
technique for hosts and routers to dynamically tunnel IPv6
packets over IPv4 routing infrastructure
0:0:0:0:0:0:13.1.68.3 => :: 13.1.68.3
IPv4-mapped IPv6 address
represent the addresses of IPv4-only nodes (those that do not
support IPv6) as IPv6 addresses
IPv4-only IPv6-compatible addresses are sometimes used/shown for
sockets created by an IPv6-enabled daemon, but only binding to an IPv4
address. These addresses are defined with a special prefix of length 96
(a.b.c.d is the IPv4 address):
0:0:0:0:0:FFFF:129.144.52.38/96 => :: FFFF:129.144.52.38/96
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http://www.tldp.org/HOWTO/Linux+IPv6-HOWTO/x324.html
Format Prefix
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Format Prefix :
– Leading bits indicate specific type of an IPv6
address
– The variable-length field
– Represented by the notation:
IPv6-address/prefix-length
Example : the 60-bit prefix 12AB00000000CD3
12AB:0000:0000:CD30:0000:0000:0000:0000/60
12AB::CD30:0:0:0:0/60
12AB:0:0:CD30::/60
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Type of Addresses
Three type of addresses
UNICAST : defines a single interface
A packet sent to a unicast address is delivered to the interface
identified by that address.
• ANYCAST : defines a set of interfaces
A packet sent to an anycast address is delivered
to one of the interfaces
• MULTICAST : defines a set of interfaces
A packet sent to a multicast address is delivered to
all interfaces identified by that address
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Address Types
• Unspecified address, 0:0:0:0:0:0:0:0 or ::
• Loopback address, 0:0:0:0:0:0:0:1 of ::1
• Global address, 2000::/3 and E000::/3
currently only 2000::/3 is being assigned
• Link local address, FE80::/64
• Site local address, FEC0::/10
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IPV6 Address Allocation
Allocation
Prefix bit
Prefix
form at
fraction of
address
apace
Reserved
0000 0000
0::/8
1/256
Unassigned
0000 0001
100::/8
1/256
Reserved for NSAP Allocation
Reserved for IPX Allocation
0000 001
0000 010
200::/7
400::/7
1/128
1/128
Unassigned
0000 011
600::/7
1/128
Unassigned
0000 1
800::/5
1/32
Unassigned
0001
1000::4
1/16
Aggregatable Global Unicast Addresses
001
2000::/3
1/8
Unassigned
010
4000::/3
1/8
Unassigned
011
6000::/3
1/8
Unassigned
100
8000::/3
1/8
Unassigned
101
A000::/3
1/8
Unassigned
110
C000::/3
1/8
Unassigned
1110
E000::/4
1/16
Unassigned
1111 0
F000::/5
1/32
Unassigned
1111 10
F800::/6
1/64
Unassigned
1111 110
FC00::/7
1/128
Unassigned
1111 1110 0
FE00::/9
1/512
Link-Local Unicast Addresses
Site-Local Unicast Addresses
Multicast Addresses
1111 1110 10
1111 1110 11
1111 1111
FE80::/10
FEC0::/10
FF00::/8
1/1024
1/1024
1/256
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Address Registries
Address registries for IPv6 are the same one as
for IPv4, ARIN,RIPE and APNIC.
• Only large network providers will ever obtain
addresses directly from the registries, such as
UNINET : one such provider in Thailand
• If a /35 prefix is allocates, the registry internally
will reserve a /32.
• The basic unit of assignment to any organization is
a /48 prefix
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Aggregatable Unicast Address
Three level hierarchy:
• Public Topology : providers and
exchanges who provide public
Internet transit services
(P1, P2, P3, P4, X1, X2, P5 and P6)
P3
P1
x2
X1
P2
P4
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Site Topology : does not provide
public transit service to nodes
outside of the site
(S1, S2, S3, S4, S5 and S6)
S1
S2
P5
S4
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S5
P6
S3
S6
Interface Identifier: interfaces on
links
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Aggregatable Unicast Address
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13
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FP
TLA ID
RES
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NLA ID
Public Topology
FP=Format
Prefix= 001
TLA= Top Level Aggregation
RES= Reserved
NLA=Next-Level Aggregation
SLA=Site-Level Aggregation
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SLA ID
64 bits
Interface ID
Site
Topology
Interface
Identifier
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Header Comparison
0
15 16
vers hlen
20
bytes
TOS
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flags
protocol
frag offset
header checksum
source address
destination address
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options and padding
pay load length
40
bytes
flow label
next header
hop limit
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source address
Added: (2)
– Traffic class
– flow label
destination address
IPv6
Changed: (3)
– total length=> payload
– protocol => next header
– TTL=> hop limit
IPv4
vers traffic class
Removed (6)
– ID, Flags, frag offset
– TOS, hlen
– header checksum
total length
identification
TTL
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Expanded
– address 32 bits to 128 bits
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IPv6 Node Configuration
• Ethernet address is an IEEE EUI-48
• Node address is an IEEE EUI-64
• EUI-48 can be converted into an EUI-64 by inserting
the bits FF FE between the 3 rd and 4th octets
EUI-48
EUI-64
00:06:5B:DA:45:AD = 00:06:5B:FF:FE:DA:45:AD
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Auto configuration
“Plug and play” feature
• Stateless mode :via ICMP (no server required)
Prefix
4c00::/80
Link Address
00:A0:C9:1E:A5:B6
IPv6 Address
4c00::A0:C9FF:EF1E:A5B6
Router adv.
• Stateful server mode : via DHCP
00:A0:C9:1E:A5:B6
DHCP
server
DHCP request
DHCP response
4c00::A0:C9FF:FE1E:A5B6
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Multimedia Support
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Applications reserve resources in advance
via Flow Label
Workstation
Flow1
File Server
Flow2
Multimedia
Server
PC
All packets belonging to the same flow must be sent with
the same source/destination address, priority, and flow label
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Security
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Authentication/Confidential
Authentication:
– MD5 based
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Confidential :
– payload encryption
– Cipher Block Chaining mode of the Data
Encryption Standard (DES-CBC)
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Support Protocols
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ICMPv6 [RFC1885]
DHCPv6
DNS extensions to support IPv6 [RFC1886]
Routing Protocols
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RIPv6 [RFC2080]
OSPFv6
IDRP
IS-IS
Cisco EIGRP
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Transition Strategy
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Dual Stack
– run both IPv4 and IPv6
Tunneling
– IPv6 packet over IPv4 infrastructure
Header Translation
– IPv4-only by header translation
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Dual Stack
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Dual stack hosts support both IPv4 and IPv6
Determine stack via DNS
Application
TCP
IPv6 IPv4
Ethernet
IPV6
Dual stack host
IPv4
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Tunneling: automatic tunneling
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Encapsulate IPv6 packet in IPv4
Rely on IPv4-compatible IPv6 address
IPv6 host
::1.2.3.4
R1
IPv4
Network
2.3.4.5
::2.3.4.5
6 traffic
flow label
payload len
next
hops
src = ::1.2.3.4
(IPv4-compatible IPv6 adr)
dst = ::2.3.4.5
(IPv4-compatible IPv6 adr)
payload
IPv4/6 host
2.3.4.5
R2
2.3.4.5
4 hl TOS
len
frag id
frag ofs
TTL
prot
checksum
src: 1.2.3.4
dst: 2.3.4.5
6 traffic
flow label
4 hl TOS
len
frag id
frag ofs
TTL
prot
checksum
src: 1.2.3.4
dst: 2.3.4.5
6 traffic
flow label
payload len
payload len
next
hops
next
hops
src = ::1.2.3.4
(IPv4-compatible IPv6 adr)
src = ::1.2.3.4
(IPv4-compatible IPv6 adr)
dst = ::2.3.4.5
(IPv4-compatible IPv6 adr)
dest = ::2.3.4.5
(IPv4-compatible IPv6 adr)
payload
payload
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Tunneling : configured tunneling
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Encapsulate IPv6 packet in IPv4
Rely on IPv6-only address
IPv6 address
(IPv4-compatible
address are
unavailable)
IPv6 host
::1:2:3:4
R1
::2:3:4:5
6 traffic
flow label
payload len
next
src = ::1:2:3:4
(IPv6 adr)
dst = ::2:3:4:5
(IPv6 adr)
payload
hops
IPv6 host
:: 2:3:4:5
IPv4
Network
R2
::2:3:4:5
R2
4 hl TOS
len
frag id
frag ofs
TTL
prot
checksum
src = R1
dst =R2
6 traffic
flow label
payload len
next
src =::1:2:3:4
(IPv6 adr)
hops
6 traffic
flow label
payload len
next
hops
src = ::1:2:3:4
(IPv6 adr)
dst = ::2:3:4:5
(IPv6 adr)
payload
dst = ::2:3:4:5
(IPv6 adr)
payload
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Header Translation
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

Full IPv6 system
need to support few IPv4-only systems
rely on
IPv6 host
IPv4-mapped
::1:2:3:4
IPv6 address
R1
::2:3:4:5
IPv4 host
2.3.4.5
IPv6
Network
R2
2.3.4.5
::2.3.4.5
6 traffic
flow label
6 traffic
flow label
payload len
next
payload len
next
src = ::1:2:3:4
(IPv6 adr)
dst = ::2.3.4.5
(IPv6 adr)
payload
hops
src = ::1:2:3:4
(IPv6 adr)
dst = ::2.3.4.5
(IPv6 adr)
hops
4 hl TOS
len
frag id
frag ofs
TTL
prot
checksum
src = R1
dst =R2
payload
payload
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Migration Steps
1. Upgrade DNS servers to handle IPv6 Address
2. Introduce dual stack systems that support IPv4
and IPv6
3. Rely on tunnels to connect IPv6 networks
separated by IPv4 networks
4. Remove support for IPv4
5. Rely on header translation for IPv4-only systems
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Conclusion
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IPv6 will provide for future Internet growth
and enhancement
IPv6 :
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solve the Internet scaling problem
support large hierarchical address
provide a flexible transition mechanism
interoperate with IPv4
provide a platform for new Internet
functionality
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