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Internet Protocol version 6 (IPv6)
Úna Logan
Broadcom Eireann Research Ltd.
http://www.broadcom.ie
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Topics
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EURESCOM Project P803
Why IPv6?
Key IPv6 Features
IPv6 Header
Benefits of IPv6 over IPv4
IPv6 Transition Mechanisms
IPv6 Implementations & Deployment
Conclusions
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
EURESCOM Project P803
• Development of European IP Testbed between partners to
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Investigate IPv6
Investigate techniques for differentiated QoS in IP networks
Investigate different network architectures
Promote creation of European agreement, build relationships with Internet
standards bodies & industry
• IPv6
– Migration scenarios and Interworking
• Dual IP Layer, Tunneling, DNS, Compatibility
– Protocol related IPv6 issues
• Mobility, Addressing, Security and Authentication, Routing, Traffic Flows
and Multicast and Anycast
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
P803 IPv6 Network
H1
R1
H2
R2
6Bone
R
R
6Bone
R
R
H3
R3
H3
H4
R3
R4
H4
R4
H = Host
R = Router
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Why IPv6 (1)?
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New version of the Internet Protocol
Developed in the early ‘90s in the IETF
Designed as an evolutionary step from IPv4
Lack of Address Space was the driving force behind the new
Internet Protocol
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Why IPv6 (2)?
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Other kinds of markets will develop
– Nomadic Personal Computing Devices
– Networked Entertainment
– Device Control
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IPv6 can provide the management and control needed
– Common protocol that can work over a variety of networks
– Large scale routing and addressing
– Communicates with current generation of computers
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Meets today's requirements and the requirements of these
emerging markets
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Key IPv6 Features(1)
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Expanded Addressing Capabilities / Efficient Routing
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IPv6 increases the IPv4’s address size from 32 bits to 128 bits
Address Autoconfiguration
Unicast, Anycast and Multicast Addresses
Hierarchical Addressing Structure
Header Format Simplification
– New streamlined header
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Improved Support for Options / Extensions
– Allows efficient forwarding
– Ability to add new options in the future
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Key IPv6 Features(2)
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Flow Labeling Capability
– Labeling of packets belonging to particular traffic "flows" for which the
sender requests special handling
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Mobility
– Built in Route Optimisation
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Security
– Authentication and Encryption.
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
IPv6 Packet Header Format
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32 bits
Ver : Version number
TC : (Traffic Class)Identify different
classes or priority
Flow Label : Request for special
handling by routers within a network
Payload Length : Length of the
remainder of the packet following the
IPv6 header
Next Header : Type of header
following the IPv6 header
Hop Limit : Limitation for the impact
of routing loops
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Ver
TC
Flow Label
Payload Length
Next Header Hop Limit
Source
Address
Destination
Address
IPv6 Flow Label
•Differentiated Services : Flow Label Field
–Used by hosts to label packets that
require special handling by routers
TC
Flow Label
•Handling can be conveyed to routers
–By a control protocol, e.g... RSVP
–By information within the flow's packets themselves
•Integrated Services : Traffic Class
–Enables a source to identify the desired delivery priority of its packets, relative to
other packets from the same source
•The Priority values are divided into two ranges
–Traffic that "backs off" in response to congestion, such as TCP traffic
–Traffic that does not back off in response to congestion, e.g..., "real-time" traffic
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Specialised Extension Headers
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Destination
Options
Location
– Between the IPv6 header
and before the upper layer
headers in a packet
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Authen
-tication
Efficient
– Most not examined or
processed until the packet
reaches it’s destination
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Encapsulating
Sec Payload
Optional
Fragment
Routing
Destination
Options
Hop-by-Hop
Options
IPv6 Header
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Extension Headers
Upper Layers
Packet Size and Fragmentation
• High packet latency hinders audio and video streams
• Fragmentation is a major source of high latency under IPv4
• IPv4 provides fragmentation at any point in the path
– Routers along the path a packet travels perform fragmentation by so that
fragments are at most the size of next-hop link MTU
• IPv6 provides end-to end fragmentation
– A source alone performs fragmentation by using a path MTU discovery
algorithm
• Fragmentation field has moved to an extension header
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Voice over IPv6
• Problems with voice over IP today
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Limited bandwidth
Also, in an Internet connection, the bandwidth can be very inconsistent
Latency
Unpredictable latency times
• Improvements for voice over IPv6
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Limited bandwidth is not a protocol issue
More efficient routing system
More Efficient End-to-End fragmentation will improve latency
Still unpredictable latency times!
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Benefits of IPv6 over IPv4 (1)
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Addressing scheme
– IPv4’s workarounds (e.g.. DHCP and NAT, CIDR) only delay the inevitable!
– Address Autoconfiguration reduces set up costs and provides easy
renumbering of sites
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Efficient Routing
– Lack of uniformity in IPv4’s hierarchical system, limited addresses…
=> reduces performance, increases routing complexity and requires more
routing information in backbone routers
– IPv6’s large hierarchical address space allows efficient routing.
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Simplified Reworked Packet Structure
– Extension headers can be worked in as needed
– With IPv6, most options are stored in the Extension headers, reducing
processing time at each hop.
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Benefits of IPv6 over IPv4 (2)
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Improved Support for Mobility
Home Node
– Built in Route Optimisation
• Direct routing to a mobile node
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QoS
– Improved Flow Handling efficiency
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Security
IPv4
IPv4
– Built-in, Mandatory Security
IPv6
Sender
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Mobile Node
P803 Mobility
Correspondent Router
Node
Home Agent
6Bone
Home Agent Router
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Router
IPv6 Implementations
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Over 50 IPv6 implementations completed or underway worldwide
Host Implementations
– Apple, Digital UNIX, FreeBSD, Linux, Microsoft, Solaris 2 (Sun), VMS
(DEC)…
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Router Implementations
– 3Com, Bay Networks, Cisco Systems, Digital, IBM, Ipsilon, Telebit...
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
The Transition to IPv6 (1)
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IPv4
Header
The Transition Features
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Incremental upgrade and deployment
Minimal upgrade dependencies
Low start-up costs
Easy Addressing
IPv6
Header
Transport Layer
Header
Data
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encaps.
decaps.
IPv6
Header
Transport Layer
Header
Data
The Transition Mechanisms
– Dual IP layer technique
– Addressing structures that embed IPv4 addresses within IPv6 addresses
– Tunnelling IPv6 packets over IPv4 routing infrastructures
• Encapsulates IPv6 packets in IPv4 packets
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
The Transition to IPv6 (2)
– Network Address Translation-Protocol Translation (NAT-PT)
• Allows IPv6-only nodes to interoperate with IPv4-only nodes
• IPv6 DNS
– IETF designers have defined DNS Extensions to Support IPv6
– Creates a new 128-bit DNS record type that will map domain
names to an IPv6 address
– Reverse lookups based on 128-bit addresses are also defined
• Application Modification for IPv6
– No direct access to the network stack - requires no updating to run in
the dual-stack environment
– Directly interfacing with IP and related components - requires updating
– Directly interfacing with both IPv4 and IPv6 - requires more extensive
updating
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
The 6Bone
• Launched in July 1996
• Virtual network
– Layered on top of portions of the physical IPv4-based Internet to support
routing of IPv6 packets
• Test network
– Allows the IPv6 protocol features and interoperability to be fully tested
• Currently, there 41 countries on the 6Bone
• Other similar initiatives
– Internet2 (http://www.Internet2.edu/)
– The Wide Project
(http://www.v6.wide.ad.jp/)
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Conclusions
• Sooner or later the address space will run out!
• IPv6 Deployment
– Only experimental
– Vendors appear committed to the development of IPv6
– The core set of IPv6 protocols due to be fully standardised this
year
• Most IPv6 functionality has been retro-fitted into IPv4
• No substitute to a protocol designed from the ground up with
scaleable addressing, advanced routing, security, QoS and related
features
• IPv6 provides the platform for new Internet functionality needed in
the near future
AIMS’99 Workshop
Heidelberg, 11-12 May 1998
Additional Information
• http://www.playground.sun.com/pub/html/ipng-main.html
– Pointers to current Specifications and implementations updated on a
regular basis
• http://www.ietf.org/
– Information on the IETF organisation, Internet Standards, Drafts and RFC s
• http://www.eurescom.de/
– Information on the P803 European IP Testbed
• http://www.6bone.net/
– Information about the 6Bone and what you need to know in order to
participate
AIMS’99 Workshop
Heidelberg, 11-12 May 1998