Internet Protocol Version 6 IPv6

1
Internet Protocol Version 6 (IPv6)

• CSCI 397C- Advanced Network Management
• Sriram Raghunathan

2
IPv6 (IPng)

• IPng was recommended by the IPng Area Directors
  of the Internet Engineering Task Force at the
  Toronto IETF meeting on July 25, 1994, and
  documented in RFC 1752, "The Recommendation for
  the IP Next Generation Protocol" 1. The
  recommendation was approved by the Internet
  Engineering Steering Group on November 17, 1994
  and made a Proposed Standard.

3
Introduction

• In 1973, TCP/IP was introduced to the ARPANET,
  which at that time connected about 250 sites and
  750 computers
• In the following two decades since that, the
  Internet has grown into the dominant form of
  global information communication.
• TCP/IP has mushroomed into a family of protocols
  that provide a wealth of connectivity services.

4
Introduction (continued)

• The continued exponential growth of the Internet
  has exposed underlying inadequacies in the
  network's current technology. Today's base
  technology, Internet Protocol version 4 (IPv4)
  was last revised in 1981 (RFC791), and for the
  last several years the Internet Engineering Task
  Force has been developing solutions for these
  inadequacies. This solution, which has been given
  the name IPv6, will become the backbone for the
  next generation of communication applications.

5
IPv6 Critical Technology for Network
Connectivity in the 21st Century

• Twenty years from now the Internet will be
  routinely used in ways just as unfathomable to
  us, Virtually all the devices with which we
  interact, at home, at work, and at play, will be
  connected to the Internet the possibilities are
  endless, and the implications staggering.
• Enabling the convergence of all these
  capabilities will be "The Network", an evolution
  of the current Internet, but still based on the
  TCP/IP protocol. To function within this new
  paradigm TCP/IP must evolve too, and the first
  significant step in that evolution is the
  development of the next generation of the
  "Internet Protocol," Internet Protocol version 6,
  or IPv6.

6
IPv6 Overview

• It is a new version of the Internet Protocol,
  designed as a successor to IP version 4 2 and
  is assigned IP version number 6 and is formally
  called IPv6 3.
• IPv6 was designed to take an evolutionary step
  from IPv4. It was not a design goal to take a
  radical step away from IPv4. Functions that work
  in IPv4 were kept in IPv6, but functions that
  didn't work were removed.

7
IPv6 Overview (continued)

• The changes from IPv4 to IPv6 fall primarily into
  the following categories
• Header Format Simplification
• Improved Support for Extensions and Options
• Expanded Addressing Capabilities
• Flow Labeling Capability
• Authentication and Privacy Capabilities

8
IPv6 Header Format

• IPv6 also improved packet headers, which are
  quite different than IPv4's packet headers. IPv6
  uses a header with a fixed length. In contrast,
  IPv4's packet header is variable in size, which
  creates more work for routers.
• With IPv6, there will be the capability to define
  additional features such as QOS by using a
  chaining mechanism. To keep the header as simple
  as possible, the essential packet data resides in
  the standard IPv6 header, and one field of the
  header specifies whether the payload begins after
  the header or whether there's another header.

9
IPv6 Header Format (continued)

• Additional IPv6 header types include routing
  information, security encapsulation (encryption),
  and fragmentation. Each of these headers has the
  same "next header" field, which specifies how the
  data succeeding it should be treated -- as the
  payload or as an additional header.
• The Ipv6 header has a fixed length of 40 bytes,
  consisting of the following fields as shown in
  Fig. 1.

10
IPv6 Header Format (continued)
11
IPv6 Header Format (continued)

• Version 4-bit Internet Protocol version number
  6.
• Priority 4-bit Priority value. See IPv6 Priority
  section.
• Flow Label 24-bit field. See IPv6 Quality of
  Service section.
• Payload Length 16-bit unsigned integer. Length
  of payload, i.e., the rest of the packet
  following the IPv6 header, in octets.
• Next Header 8-bit selector. Identifies the type
  of header immediately following the IPv6 header.
  Uses the same values as the IPv4 Protocol field
  4.
• Hop Limit 8-bit unsigned integer. Decremented by
  1 by each node that forwards the packet. The
  packet is discarded if Hop Limit is decremented
  to zero.
• Source Address 128 bits. The address of the
  initial sender of the packet. See 5 for
  details.
• Destination Address 128 bits. The address of the
  intended recipient of the packet (possibly not
  the ultimate recipient, if an optional Routing
  Header is present).

12
IPv6 Extension Headers

• The IPv6 extension headers which are currently
  defined are
• Routing---Extended Routing (like IPv4 loose
  source route)
• Fragmentation---Fragmentation and Reassembly
• Authentication---Integrity and Authentication,
  Security
• Encapsulation---Confidentiality
• Hop-by-Hop Option---Special options which require
  hop by hop processing
• Destination Options---Optional information to be
  examined by the destination node

13
Address Expansion

• The number one issue driving the need for IPv6 is
  the rapid exhaustion of the available IPv4
  network addresses.
• Currently, IPv4 uses 32-bit addresses, which are
  represented as 4 bytes
• IPv6 uses 128-bit addresses, offering a
  theoretical maximum of 340 trillion, trillion,
  trillion hosts. To compare with the earth
  surface, it is 6.210E22 IPv6 addresses per
  square foot of earth surface.

14
Address Expansion (continued)

• There are three types of IPv6 addresses. These
  are unicast, anycast, and multicast.
• Unicast addresses identify a single interface.
• Anycast addresses identify a set of interfaces
  such that a packet sent to an anycast address
  will be delivered to one member of the set.
• Multicast addresses identify a group of
  interfaces, such that a packet sent to a
  multicast address is delivered to all of the
  interfaces in the group.

15
IPv6 Routing

• IPv4 uses a technique called Classless
  InterDomain Routing (CIDR), which allows flexible
  use of variable-length network prefixes.
• Routing in IPv6 is almost identical to IPv4
  routing under CIDR except that the addresses are
  128- bit IPv6 addresses instead of 32-bit IPv4
  addresses.
• IPv6 also includes simple routing extensions that
  support powerful new routing functionality. These
  capabilities include
• Provider Selection (based on policy, performance,
  cost, etc.)
• Host Mobility (route to current location)
• Auto-Readdressing (route to new address)

16
IPv6 Quality-of-Service Capabilities

• The Flow Label and the Priority fields in the
  IPv6 header may be used by a host to identify
  those packets for which it requests special
  handling by IPv6 routers, such as non-default
  quality of service or "real-time" service. This
  capability is important in order to support
  applications that require some degree of
  consistent throughput, delay, and/or jitter.
  These types of applications are commonly
  described as "multi-media" or "real-time"
  applications.

17
IPv6 QoS Capabilities (continued)

• Flow Labels
• A flow is a sequence of packets sent from a
  particular source to a particular (unicast or
  multicast) destination for which the source
  desires special handling by the intervening
  routers.
• A flow label is assigned to a flow by the flow's
  source node. New flow labels must be chosen
  (pseudo-) randomly and uniformly from the range 1
  to FFFFFF hex.
• All packets belonging to the same flow must be
  sent with the same source address, same
  destination address, and same non-zero flow label.

18
Priority

• The 4-bit Priority field in the IPv6 header
  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
  Values 0 through 7 are used to specify the
  priority of traffic for which the source is
  providing congestion control, and Values 8
  through 15 are used to specify the priority of
  traffic that does not back off in response to
  congestion.

19
Priority (continued)

• For congestion-controlled traffic, the following
  Priority values are recommended for particular
  application categories
• 0 Uncharacterized traffic
• 1 "Filler" traffic (e.g., netnews)
• 2 Unattended data transfer (e.g., email)
• 3 (Reserved)
• 4 Attended bulk transfer (e.g., FTP, HTTP, NFS)
  
• 5 (Reserved)
• 6 Interactive traffic (e.g., telnet, X)
• 7 Internet control traffic (e.g., routing
  protocols, SNMP)

20
Priority (continued)

• For non-congestion-controlled traffic, the lowest
  Priority value (8) should be used for those
  packets that the sender is most willing to have
  discarded under conditions of congestion (e.g.,
  high-fidelity video traffic), and the highest
  value (15) should be used for those packets that
  the sender is least willing to have discarded
  (e.g., low-fidelity audio traffic). There is no
  relative ordering implied between the
  congestion-controlled priorities and the
  non-congestion-controlled priorities.

21
Security

• The number one concern of senior IT professionals
  and CEOs about connecting their organization with
  Intranets and to the Internet is security. The
  good news is that built into IPv6 are a whole
  host of new security features, including system
  to system authentication and encryption based
  data privacy.

22
Security (continued)

• Two long-sought security options have already
  been defined as extensions to the IPv6 header.
• The first mechanism, called the "IPv6
  Authentication Header", is an extension header
  which provides authentication and integrity
  (without confidentiality) to IPv6 datagrams.
• The second security extension header provided
  with IPv6 is the "IPv6 Encapsulating Security
  Header". This mechanism provides integrity and
  confidentiality to IPv6 datagrams.

23
The Transition to IPv6

• While a primary design goal of IPv6 is to ease
  the transition from and co-existence with IPv4,
  converting today's tens of millions of IPv4 based
  systems to IPv6 will be a major challenge.
• The key transition objective is to allow IPv6 and
  IPv4 hosts to interoperate. A second objective is
  to allow IPv6 hosts and routers to be deployed in
  the Internet in a highly diffuse and incremental
  fashion, with few interdependencies. A third
  objective is that the transition should be as
  easy as possible for end- users, system
  administrators, and network operators to
  understand and carry out.

24
The Transition to IPv6 (continued)

• The IPv6 transition mechanisms provides a number
  of features, including
• Incremental upgrade and deployment.
• Minimal upgrade dependencies.
• Easy Addressing.
• Low start-up costs.

25
The Transition to IPv6 (continued)

• The mechanisms employed by the IPv6 transition
  mechanisms include
• An IPv6 addressing structure that embeds IPv4
  addresses within IPv6 addresses, and encodes
  other information used by the transition
  mechanisms.
• A model of deployment where all hosts and routers
  upgraded to IPv6 in the early transition phase
  are "dual" capable (i.e. implement complete IPv4
  and IPv6 protocol stacks).
• The technique of encapsulating IPv6 packets
  within IPv4 headers to carry them over segments
  of the end-to-end path where the routers have not
  yet been upgraded to IPv6.
• The header translation technique to allow the
  eventual introduction of routing topologies that
  route only IPv6 traffic, and the deployment of
  hosts that support only IPv6. Use of this
  technique is optional, and would be used in the
  later phase of transition if it is used at all.

26
IPv4 vs IPv6
27
Conclusion

• In summary, IPv6 is a new version of IP. It can
  be installed as a normal software upgrade in
  internet devices. It is interoperable with the
  current IPv4. Its deployment strategy was
  designed to not have any "flag" days. IPv6 is
  designed to run well on high performance networks
  (e.g., ATM) and at the same time is still
  efficient for low bandwidth networks (e.g.,
  wireless). In addition, it provides a platform
  for new internet functionality that will be
  required in the near future.