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IPv6
Advantages
May 2001
[email protected]
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What is IPv4?
 Version 4 of the Internet Protocol
 30+ Years Old
 Incredibly successful
– Today’s Internet runs over IPv4
 IPv4 address is 32 bits
 Many add-ons
 Showing its age
application
Web, ftp,
telnet, etc.
presentation
session
transport
network
link
TCP, UDP
IPv4
Ethernet
physical
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What is IPv6?
 Version 6 of the Internet Protocol
– Version 5 was allocated to the
experimental Internet Stream Protocol
(RFC 1190)
 5+ years old
 Poised for the continued growth
and success of the Internet
 IPv6 address is 128 bits
application
Web, ftp,
telnet, etc.
presentation
session
transport
network
link
TCP, UDP
IPv6
Ethernet
physical
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IPv4: A Victim of Its Own Success
 1990 - IPv4 addresses being consumed at an
alarming rate, projections show:
 Class B address space exhausted by 1994
 All IPv4 address space exhausted between 2005 - 2011
– Internet routing tables suffering explosive growth
 Internet routing today is inefficient
 Running out of Internet addresses
– Stops Internet growth for existing users
– Prevents use of the Internet for new users
– Forces users to use Private Addresses
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Interim Measures
 CIDR (Classless Inter-Domain Routing)
– Eased routing table growth
 Private addresses
– Reduced pressure on address space, but…
– Necessitated Network Address Translation, but…
 Single point of failure
 Network performance penalty
 Breaks applications that rely on end-to-end IP
addressing (FTP, DNS, others)
– Use ALGs
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More User Problems with IP today
 System administration
– Labor intensive, complex, slow, and error prone
– Subscriber networks cannot be dynamically
renumbered or configured
 Security is optional; no single standard
 No support for new protocols
– Difficult to add to the base IPv4 technology
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Interim Measures Helped, But …
 Address space consumption slowed, but Internet
growth accelerated
– “Everything to the Internet”
 1B mobile users by 2005
 1B Internet users by 2005
 90% of all new mobile phones will have internet
access by 2003 (Morgan Stanley Dean Witter, May 2000)
 Projections of address space exhaustion by 2010
– Pain Sooner (Europe and Asia)
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… a longer term solution
IP next generation (IPng)
 1991: Work starts on next generation Internet protocols
– More than 6 different proposals were developed
 1993: IETF forms IPng Directorate
– To select the new protocol by consensus
 1995: IPv6 selected
– Evolutionary (not revolutionary) step from IPv4
 1996: 6Bone started
 1998: IPv6 standardized
 Today: Initial products and deployments
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IPv6 Base Technology
Wins
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Design Philosophy
 Recognizable yet simplified header format
 Reduce common-case processing cost of packet
handling
 Keep bandwidth overhead low in spite of
increased size of the address
 Flexible and extensible support for option
headers
 Design optimised for 64-bit architecture
– Headers are 64-bit aligned
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IPv6 Header – Comparison with IPv4
bit
0
8
Version
IHL
16
Service Type
Identifier
Time to Live
24
Total Length
Flags
Protocol
31
Fragment Offset
bit
0
4
12
16
24
Class
Flow Label
Payload Length
Next Header
Version
31
Hop Limit
Header Checksum
32 bit Source Address
128 bit Source Address
32 bit Destination Address
Options and Padding
IPv4 Header
20 octets, 12 fields, including 3 flag bits
+ fixed max number of options
Changed
128 bit Destination Address
Removed
IPv6 Header
40 octets, 8 fields
+ Unlimited Chained Extension (options) Header
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IPv6 Extension Headers
 IP options have been moved to a set of optional
Extension Headers
 Extension Headers are chained together
IPv6 Header TCP Header
Application Data
Next = TCP
IPv6 Header Fragment Hdr Security Hdr
Next = Frag
Next = Security
Next = TCP
TCP Header
Data
Frag
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IPv6 Header
Performance Wins Layout
 Fixed Size IPv6 Header
– Unlike IPv4 - Options not limited at 40 bytes
 Fewer fields in basic header
– faster processing of basic packets
 64 Bit Alignment Header/Options
 Efficient option processing
– Option fields processed only when present
– Processing of most options limited performed
only at destination
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IPv6 Header
Performance Wins Processing
 Remove checksum from Network Layer
– Datalinks are more reliable these days
– Upper Layer checksums are now mandatory (for
example, TCP, UDP, ICMPv6)
 No fragmentation in the network
– Reduce load on routers
– Easier to implement in hardware
– Easy for Layer 3 switching of IP
 Minimum link MTU is 1280 bytes
– From 68 in IPv4
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The power of IPv6
Addressing
Management
Security
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Addressing Model (RFC 2373)
 Addresses assigned to interfaces
 No change from IPv4 model
 Interfaces typically have multiple addresses
 Subnets associated with single link
 A link is a link-layer (layer 2) domain e.g. LAN
 No change from IPv4 model
 Multiple subnets on same link
 IPv6 addresses have scope and lifetime
Global
Site-Local
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Link-Local
IPv6 Unicast Address
 Address = prefix of n bits + interface ID of 128-n bits
 Separate “who you are” from “where you are
connected to”
n bits
prefix
128-n bits
Interface ID
Prefix Representation <prefix>::/<n-bits>
 Aggregatable Global Unicast Address format
3FFE:0301:DEC1:: 0A00:2BFF:FE36:701E
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The power of IPv6
Addressing
Management
Security
Other IPv6 goodies
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Network Management
 Address Autoconfiguration
– Designed for hosts
 It is assumed that routers are configured by some
other means
– Provides “Plug-and-Play” capability
– Defines methods for obtaining routable address(es):
 Link Local Address (No router or server required)
 Stateless mechanism (Router advertisements provide
prefix)
 Stateful mechanism (Server provides address ( DHCP)
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Network Management
 Renumbering IPv6 hosts is easy
– Add a new prefix to the router
– Reduce the lifetime of the old prefix
– As nodes deprecate the old prefix, they begin
using the new prefix for new connections
– No network downtime
 Renumbering IPv6 routers
– New protocol: Router Renumbering (RFC 2894)
 An end of ISP “lock in”!
– Improved competition
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Mobile IPv6
 IPv6 Mobility is based on core features of IPv6
– The base IPv6 was designed to support Mobility
– Mobility is not an “Add-on” features
 IPv6 Neighbor Discovery and Address
Autoconfiguration allow hosts to operate in any
location without any special support
 No single point of failure (Home Agent)
 More Scalable : Better Performance
– Less traffic through Home Link
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– Less redirection / re-routing (Traffic Optimisation)
The power of IPv6
Addressing
Management
Security
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IPv6 Mandates IP Security
 Security features are standardized and mandated
– All implementations must offer them
 Extensions to the IP protocol suite (RFC 2401)
– Authentication (Packet signing)
– Encryption (Data Confidentiality)
 Operates at the IP layer
– Invisible to applications
 Protects all upper layer protocols
 Protects both end-to-end and router-to-router
(“secure gateway”)
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Summary
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A decade of design and testing
Core IETF specs have reached Draft Standard status
No
Interne
t
Draft
No
Yes
Technically
complete
1991
RFC
Proposed
Standard
Yes
RFC
Draft
Standard
Multiple
Interoperable
Implementations
6bone test bed
1998
1996
timeline
Yes
Significant
Operational
Experience
Today
RFC
Internet
Standard
Available TODAY in commercial products
IPv6 key features and Advantages
 Increased Address Space
 Efficient and extensible IP datagram
 Improved host and router discovery
 Plug and Play
 Enhancements for Quality of Service (QoS)
 Improved Mobile IP support
 IPsec mandated
 Coexistence with IPv4
 Extensibility of the Architecture
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Conclusion
 IPv6 Solves many of the problems caused by the
IPv4 success and more...
 The technology you’ve been waiting for is here…
Start deploying today!
Imagine what IPv6 can do for you!
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Questions?
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