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The IPv6, 6Bone and Us: A Concept that Would Help Us Solve Several Problems We Face Today!

The IPv6, 6Bone and Us: A Concept that Would Help Us Solve Several Problems We Face Today! . Prof. Rahul Banerjee Coordinator: Centre for Software Development Assistant Dean: DLP Division Birla Institute of Technology and Science, Pilani (India)

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The IPv6, 6Bone and Us: A Concept that Would Help Us Solve Several Problems We Face Today!

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  1. The IPv6, 6Bone and Us: A Concept that Would Help Us Solve Several Problems We Face Today! Prof. Rahul Banerjee Coordinator: Centre for Software Development Assistant Dean: DLP Division Birla Institute of Technology and Science, Pilani (India) Home Page: http://www.bits-pilani.ac.in/~rahul/ (c) Rahul Banerjee, BITS, Pilani (India)

  2. Introduction • What shall we cover today? • The IPv6: What, Why and How? • Problems being faced by the IPv6 Researchers • The 6Bone Initiative: What, Why and How? • The Project IPv6@BITS: A Brief Introduction • The learning objectives: • Realisation of the potential as well as problems related to the next generation Internet Protocol: IPv6 • Realisation of advantages of using the 6Bone Facilities for collectively solving the technology-specific challenges lying ahead • A look into the Project IPv6@BITS model of cooperative research in internetworking technologies (c) Rahul Banerjee, BITS, Pilani (India)

  3. Learning about the audience • May I know whether the participants have any previous IPv6 experience? • Idea here is to leave out certain introductory aspects of IPv6 in case I am addressing an audience having such prior experience! (Default plan assumes only an IPv4 background.) (c) Rahul Banerjee, BITS, Pilani (India)

  4. IPv6: What, Why and How? • IPv6 stands for the Internet Protocol Version 6. • The IPv6 is the successor of the IPv4 which was designed in keeping with the technologies of the early Seventies. • It does away with certain features of the IPv4 while adds many new features. • One basic advantage is the enlarged address space (adequate for a reasonably long time). • There exist many practical problems before the world could finally switchover from IPv4 to the IPv6. It would be premature to state that IPv6 is answer to all our problems. On the contrary, while it offers an enlarged address-space, many experts view it an overly complex scheme to implement. (c) Rahul Banerjee, BITS, Pilani (India)

  5. IPv6: Major Design Goals • Simplification of the basic protocol. This was partially achieved by: • providing a common format for all the headers, • eliminating the IPv4 procedure used for ‘hop-by-hop’ segmentation handling & • doing away with the header checksum, padding, header length and options fields. This, however, does not mean that it is simpler to implement it under the current constraints of the Internet. • Reduction in the packet processing time at the routers. Simplification helped in achieving this goal. (c) Rahul Banerjee, BITS, Pilani (India)

  6. IPv6: Major Design Goals … • Providing support for a very large number of addresses. Providing 128-bit source address as well as 128-bit destination address took care of this objective. It remains , however, debatable whether 128-bit was the best choice possible. • Providing support for flow specification and priority for the time-sensitive applications. Introducing the Flow Label and Priority fields made it possible. There remains a major problem, however, in the actual use of these enhancements -- since, there exists no scheme for guiding the developers on the actual implementation of systems to support the Flow Label feature. BITS Pilani has recently submitted an Internet Draft to the IETF in order to suggest a simple solution to this problem. (c) Rahul Banerjee, BITS, Pilani (India)

  7. IPv6: Major Design Goals … • Providing reasonable support for multicasting. • Allowing smooth extensibility and modifiability in the years ahead. • Permitting Stateless as well as StatefulAddressAutoconfiguration. • Adding optional security features like encryption and authentication in the basic protocol itself. • Providing a certain degree of Interoperability with other protocol families. (c) Rahul Banerjee, BITS, Pilani (India)

  8. The IPv6 Base Header Structure 0 4 12 16 31 Ver. T. Class Flow Identifier (4-bit) (8-bit) (20-bit) Payload Length Next Header Hop Limit (16-bit) (8-bit) (8-bit) Source Address (128-bit) Destination Address (128-bit) (c) Rahul Banerjee, BITS, Pilani (India)

  9. The IPv6 Extension Headers (as defined till date) Hop-by-Hop Option Header Destination Options Header Routing Header Fragment Header Authentication Header Encrypted Security Payload (c) Rahul Banerjee, BITS, Pilani (India)

  10. The IPv6 Destination Option Header • The IPv6 Destination Options Header is identified by the Header Type code ’60’. • It is used as a general purpose Destination Option-based Header that may specify one or more options in its Option Type field (uniquely identified by an appropriate code) to be processed by the designated destination node. • The Header Extension Length field carries an 8-bit number that represents exactly how many 64-bit words, excluding the first 64-bit word, do exist in the Destination Option Header. (c) Rahul Banerjee, BITS, Pilani (India)

  11. The IPv6 Destination Option Header … • The Header Extension Length field carries an 8-bit number that represents exactly how many 64-bit words, excluding the first 64-bit word, do exist in the Destination Option Header. • Option Type field is an 8-bit field that species the type of designated option; the first two higher-order bits of which specify an explicit desired action to be taken in the event of misinterpretation / ignorance of the options code by the destination node, a single bit 'C' flag specifies whether this specified option may be modified en route the destination and the remaining five bits specify a number such that the LSB encodes this option code itself. (c) Rahul Banerjee, BITS, Pilani (India)

  12. IPv6: The Hop-by-Hop Option Header • Certain situations like those requiring selective debugging, management and network monitoring etc. the Destination Option Header option may not prove adequate. The Hop-by-Hop Option Header is used in such cases (like multicast routing management, RSVP etc.) so that the necessary information could be communicated to all the intermediate routers, who would not bother to process the Destination Option Header by default. • It is identified by the extension header code ‘0’ (zero). • Its format is as shown below: (c) Rahul Banerjee, BITS, Pilani (India)

  13. The IPv6 Hop-by-Hop Option Header .. • There exist a Jumbo Payload option, as shown below. The Option Type Header in this case is set to the code ‘194’. This option is used in the cases wherein the packet length of a packet of larger than 64 Kbytes size is to be used, length of which could not be expressed by the 16-bit length field. • A Router Alert Option exists as well. The primary purpose of such an option is to alert / notify the intermediate routers that the packet-in-question does have some substantial information that demands a careful examination. (c) Rahul Banerjee, BITS, Pilani (India)

  14. The IPv6 Hop-by-Hop Option Header .. • It may be interesting to note that for using the Jumbo Payload option, the Length Field of the IPv6 Base Header is set to zero. Naturally, there has to be an alternative mechanism for determination of the actual length of such packets! And, this alternative mechanism involves decoding of the ‘Jumbo Payload Length’ field for computing this size. • Just like the Destination Option Header case, in this case also exactly the same padding scheme (of one or more pads) is employable. (c) Rahul Banerjee, BITS, Pilani (India)

  15. The IPv6 Routing Header Structure • The IPv6 Routing Header plays the same role as the Source Routing Option of the IPv4; i.e. it contains the list of designated intermediate Router Addresses which should be traversed by the packet-in-question (depending upon the loose / strict source routing option). (c) Rahul Banerjee, BITS, Pilani (India)

  16. IPv6 Authentication Header Features • The combination of the Destination Address and Security Parameter Index (SPI) is used to identify security association state comprising of the key, packet lifetime, chosen algorithm etc. • The said security applies to all those IPv6 packets (all fields included) which do not get altered while traveling. • The Keyed MD5 Algorithm is used by default although any other algorithm may be defined / used as well. (c) Rahul Banerjee, BITS, Pilani (India)

  17. Comments on the IPv6 Security (as likely to emerge) • All implementation initiatives aim to support authentication and encryption headers in their final version. • Authentication has been attempted to be separated from the encryption. • Several Key Distribution schemes / protocols are under active research and development. • Manual Key Configuration support may be desirable, at times. (c) Rahul Banerjee, BITS, Pilani (India)

  18. The Good Old IPv4 Header Structure Ver. IHL Type of Service Total Length 0 31 Identification Flags Fragment Offset TTL Protocol Type Header Checksum Source Address (32-bit) Destination Address (32-bit) Options+Padding (c) Rahul Banerjee, BITS, Pilani (India)

  19. A Quick Comparison of IPv6 and IPv4 1. In IPv6 the IPv4 Options were replaced by Extension Headers. 2. IPv6 has a Flow Identifier sub-field of the Flow Label field in its header primarily meant for supporting the real-time applications. 3. Traffic Classsub-field of the Flow Label field was introduced in the IPv6 header that supports priority (mainly for real-time applications). 4. The IPv6 header has Payload Length field in place of the Total Length field of IPv4. 5. The IPv6 has a Next Header Type field in place of the Protocol Type field of the IPv4. 6. The IPv6 has Hop Limit field instead of the Time-To-Live field of the IPv4. (c) Rahul Banerjee, BITS, Pilani (India)

  20. A Quick Comparison of IPv6 and IPv4 7. The IPv6 provides Autoconfiguration capability. 8. In contrast to the IPv4 which does not have any explicit provision for aiding privacy and security, the IPv6 does have built-in provisions for these requirements. 9. Unlike IPv4, the IPv6 providessupport forJumbograms. 10. Both permit Fragmentation, but the IPv6 format keeps it in an extension header specifically meant for the job unlike the IPv4 format in which this information was to be maintained in a fixed field within the IP header. 11. The IPv4 had a field called Service Type in its header which has been replaced in the IPv6 header by the 28-bit (4+24) Flow Label. 12. In IPv6, the multi-purpose Next Header field is usedto indicate the type of protocol whereas IPv4 had a Protocol Type field for this purpose. (c) Rahul Banerjee, BITS, Pilani (India)

  21. A Quick Comparison of IPv6 and IPv4 13. The IPv6 header does away with the Header Checksum field of the IPv4. 14. In IPv6, all addresses starting with eighty (80) ‘zeros’followed by sixteen (16) bits of all ‘ones’ or all ‘zeros’are considered as IPv4 addresses. 15. In IPv4, there were five address classes (A to C of Network / Host combination types, D for Multicasting and E reserved for future use).In IPv6, the IPv4 Classes have been replaced with Types. Unlike the IPv4, that permits a two-level hierarchy of network and host prefixes, the IPv6 proposes to offer multi-level hierarchyor even multiple hierarchies of prefixes. In IPv6, the first byte of the address refers to the type of address. (c) Rahul Banerjee, BITS, Pilani (India)

  22. A Quick Look at the IPv6 Address Categories • Unicast: (One station sends a packet to another single station / interface.) • Multicast: (One station sends a packet to every member station / interface belonging to a designated group.) • Anycast: (A form of packet transfer in which the packet is delivered to the nearest member of a designated group instead of sending to each group member individually.) Often used for clusters. (c) Rahul Banerjee, BITS, Pilani (India)

  23. The IPv6 Address Notations • Unlike IPv4 address notation, in which a 4-part IP address was expressed in Decimal Number System with a ‘.’ used as a separator between every two parts; an IPv6 address is expressed as an 8-part IP address expressed in Hexadecimal Number System with a ‘:’ used as a separator. • Example: ABCD:CA74:120A:4567:BDEA:FA3B:BB4C:1963 (c) Rahul Banerjee, BITS, Pilani (India)

  24. The IPv6 Address Notations … • IPv6 permits Address Abbreviation / Shorthand Notation. • Examples: • ABCD:0000:120A:0000:0000:0000:BB4C:1963 can be denoted as: ABCD:0:120A:0:0:0:BB4C:1963 -- a case of replacing leading zeros by a single zero • Similarly, this address can be further abbreviated as: ABCD:0:120A::BB4C:1963 -- a case of eliminating an all-zero part of the address (c) Rahul Banerjee, BITS, Pilani (India)

  25. The IPv6 Address Notations … • In the second example above, there are two consecutive colons. This notation is called the Double Colon notation and has the restriction that it can be used only once within a single IPv6 address. The primary reason behind this restriction is the Alignment Problem. • An IPv4 address, by prepending 96 zeros may form a valid IPv6 address. Such addresses are often written using a hybrid notation with the last 32-bits expressed in the Dot Decimal notation. • Example: ::0A00:0003 may be written as ::10.0.0.3 (c) Rahul Banerjee, BITS, Pilani (India)

  26. The IPv6 Address Notations … • The IPv4 had a Prefix Notation that has been retainedby the IPv6 as well. This involves using a normal IP address followed by a slash (/) followed by a number that represents Length of the Prefix. This Prefix Notation is useful to indicate that in any given IP address, how many bits (starting with the leftmost bit) belong to the Network-in-question. • Example: The notation A127:0:8:a123::/64 refers to a 64-bit Network Prefix in an IPv6 environment. (c) Rahul Banerjee, BITS, Pilani (India)

  27. The IPv6 Address Notations … • Globally addressable IPv6 Unicast addresses are in the IPv6 Global Unicast Address Format. • This format, as per RFC 2374, has a three level hierarchy that includes a Public Topology (the 48 bit external routing prefix), a Site Topology (typically a 16 bit subnet number), and an Interface Identifier (a 64 bit number unique at least on the local link). • The Public Topology has two or more levels of hierarchy, specifying the Top Level Aggregator (typically a high level ISP), Next Level Aggregators (zero or more mid-level ISPs) and a final Next Level Aggregator which is the end-user-site. (c) Rahul Banerjee, BITS, Pilani (India)

  28. The IPv6 Address Notations … • As of now, there are two types of Top Level Aggregator (TLA) prefixes: • First for the6bone whose first 16 bits are 3FFE::/16the top level aggregators here are called pseudo-TLA's, or pTLA's. (BITS, Pilani is likely to get the pTLA status shortly, after the two-week review process is completed.) 2.  Second for early production assignments whose first 16 bits are 2001::/16        These top level aggregators are called sub-TLA's. The sub-TLA’s are assigned by the way of a process called the International Regional Internet Registry (RIR) whereas the pTLA’s are assigned by a 6Bone community process. (c) Rahul Banerjee, BITS, Pilani (India)

  29. Other IPv6 Addressing Features • The assigned IPv6 addresses do have a limited lifetime. However, it is possible to set this lifetime to infinity, as of now. • Stateless case: No Address Servers are required in stateless mode. • Stateful case: This mode requires use of Address Servers. • Valid Address-Lifetime: • Lifetime as assigned by the Address Server in the stateful case. • Lifetime as computed on the basis of Address-Prefix Lifetime (contained in the Router Advertisement Message) in the stateless case. • An IPv6 address whose valid lifetime has expired, must not be used. • Preferred Address-Lifetime: An IPv6 address whose preferred lifetime has expired is called an Invalid Address. Such addresses can be used for the current transaction; however, these cannot be used for initiating a new connection by the TCP. (c) Rahul Banerjee, BITS, Pilani (India)

  30. An Approach to the Migration from the IPv4 to IPv6 • Gradual upgrading of the IPv4 Hosts to IPv6 Hosts. • Gradual upgrading of the IP Routers. • Building IPv6 intranets at different locations and providing them connectivity via the traditional IP Internet by using Tunneling. (Tunneling involves encapsulation of the IPv6 packets within the IPv4 packets at the sending end and removing the encapsulation at the receiving end. • Manual configuration of the Router to Router Tunnels. • Once the Routers are upgraded to IPv6, tunnels shall be no longer required. • Automatic configuration of the Host (isolated) to Router tunnels. ( This may be done by using IPv4-aware IPv6 addresses for the Router to Host communication and Anycasting technique for the Host to Router communication. ) (c) Rahul Banerjee, BITS, Pilani (India)

  31. Other Issues related to the IPv4 to IPv6 Migration / Compatibility • Use of the IPv6forceschanges in the TCP/UDP “pseudo-header” . • This also affects all protocols and processes that use IPv6 addressesirrespectiveofthe functional location of it. • Inflated size of the IP header needs to be kept in mind whenever an upper limit is to be fixed for the payload length. (c) Rahul Banerjee, BITS, Pilani (India)

  32. Migration to IPv6:Commercial Implementations in Progress Router implementations include: • 3Com, Bay Networks, Cisco, Digital, Merit, Sumitomo, Telebit, Nortel. Host implementations include: • Microsoft, Apple, Bull, Digital, FTP Software, IBM, INRIA, Linux, Novell, Pacific Softworks, Siemens Nixdorf, SCO, Sun, WIDE Consortium ( by NAIST, Hitachi, Sony and the NTT) (c) Rahul Banerjee, BITS, Pilani (India)

  33. The 6-Bone Initiative: What is it? • As per the 6Bone site statement: “The 6bone is an IPv6 Testbed that is an outgrowth of the IETF IPng project …” • The 6bone is a world wide collaborative research and development project, informally supervised by the IETF’s "Nextgenrationtransition Working Group". • It originally started as a virtual network by the way of tunneling or encapsulation. • However, as of now, it does have a few native links for IPv6 transport between IPv6-to-IPv6 networks. Migration is still one of the basic research goal of this initiative. • In the beginning, the project primarily emphasized on standards / implementations and their testability aspects. • Testing of transition and operational schemes is a major thrust area of the initiative at present. • The entire project works on the basis of the RFC 2471 that describes the IPv6 Testing Address Allocation. (c) Rahul Banerjee, BITS, Pilani (India)

  34. The 6-Bone Initiative: How do you join it? • For obtaining an IPv6 address from the 6bone: • You have to become a leaf / end site of an existing pTLA ho;lder. (This is typically a 6bone ISP which allocates your organisation a 48- bit IPv6 external routing prefix from itself). • Once you have operated for a minimum of three months, you may appy for becoming a pTLA. • For obtaining a production IPv6 address: • You must locate a sub-TLA holder to get your prefix from. • Once you get such an address, you may apply to become a sub-TLA yourself. want your own sub-TLA. • You may also obtain a public IPv6 address is to use the newly emerging 6to4 automatic tunneling mechanism. • Addresses of 6to4 type have the first 16 bits of 2002::/16, with the next 32 bits containing the IPv4 address of a router at your end. (c) Rahul Banerjee, BITS, Pilani (India)

  35. The 6-Bone Initiative: How do you join it? • How to find a suitable 6Bone Access Point? • Choose a pTLA (backbone site) or an NLA (non-backbone site), preferably the one nearer to your organisation. (In India, BITS, Pilani may provide you such an access on specific request by any authorised functionary of any organisation.) • Next, you will have to build a configured IPv4 tunnel from your IPv6 router to this access point. • For more details, you may read the online documentation / guideline available at many sites including the BITS, Pilani site at the URL: http://ipv6.bits-pilani.ac.in/ This site is known as IPv6-BITS-IN in the IPv6 world. This site also has a download facility for downloading several software tools that may be required / helpful to connect your site to the 6Bone. (c) Rahul Banerjee, BITS, Pilani (India)

  36. Any questions please? (c) Rahul Banerjee, BITS, Pilani (India)

  37. References • C. Huitema: IPv6, Second Edition, Prentice-Hall PTR, 1998. • D. Comer: Internetworking with TCP / IP , Vol..-1, PHI, 1995. • D. Comer & D. L. Stevens: Internetworking with TCP /IP, Vol.. 2-3, PHI,1994, 1993. • RFC 815 (IP Datagram Reassembly) • RFC 1042 (IP over IEEE 802.3) • RFC 1009 (Requirements for Internet Gateways) • RFC 1254 (Gateway Congestion Control) • RFC 1360 (Official Protocol Standards of the Internet Architecture Board) • RFC 1124 (Policy Issues in Interconnecting Networks) • RFC 1125 (Policy Requirements for Inter-Administrative Domain Routing) • RFC 781 (IP Timestamp) • RFC 1011 (Official IP) • RFC 1883 (Older IPv6 Specification) • RFC 1809 (IPv6 Flow Labels) (c) Rahul Banerjee, BITS, Pilani (India)

  38. References • RFC 1884 (IPv6 Addressing) • RFC 1886 (IPv6 DNS Extensions) • RFC 1887 (IPv6 Unicast Addressing) • RFC 1825 (IP Security Architecture) • RFC 1826 (IP Authentication Header) • RFC 1827 (IP Encapsulation Security Payload) • RFC 1828 (IP Authentication using MD5) • RFC 1175 (FYI : A very useful reference-list on Internetworking related information) • RFC 1147 (FYI: A list of Network Management Tools • RFC 1972 (IPv6 over Ethernet) • RFC 2019 (IPv6 over FDDI) • RFC 2023 (IPv6 over PPP) (c) Rahul Banerjee, BITS, Pilani (India)

  39. References • RFC 1208 (Glossary of Networking Terms) • RFC 1630 (Universal Resource Identifiers in the WWW) • RFC 1738 (Uniform Resource Locators) • RFC 1209 (IP over SMDS) • RFC 1971 (IPv6 Address Autoconfiguration) • Smoot Carl-Mitchell & John S. Quarterman: Practical Internetworking with TCP / IP and UNIX, Addison-Wesley, Reading, 1993. (This book does not really discuss the IPv6. This however, helps the reader to take a look at the pre-IPv6 days and realize the wisdom of evolution of the IP.) • Rahul Banerjee: Internetworking Technologies, Fifth Edition, BITS, Pilani, Dec. 2001. (To be published by the Prentice-Hall of India Pvt. Ltd. By April 2001 in expanded form.) • 6Bone Home Page at the URL: http://www.6bone.net/ (c) Rahul Banerjee, BITS, Pilani (India)

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