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1999-06-28

Litteraturstudie

Nedan sammanfattas materialet som jag hittills tittat på. Jag har skrivit på engelska för att om möjligt senare kunna återanvända texten i min slutliga rapport.

Home Networking

Since the report intends to look at the IPv6 protocol from a Home Networking-perspective, a description of the concept and available solutions today seems appropriate.

At Telia Research most of the information regarding home networking remain in the heads of the individuals working in related projects. However, one thorough description of what functionality Telias Residential Gateway (RG), the home’s connection to the outside network, may comprise is made in [10]. The report discusses different services such as DHCP, DNS, Firewall, and IP telephony. All these services helps me point out which areas I have to concentrate on, and find the equivalents in the IPv6 world.

Besides [10], lots of information about home networking can be found on the web. One can see that home networking is a hot topic in the Internet world! Additional web references to come…

IPv6 Features

The main part of my final report will consist of the evaluation of IPv6 from a home network’s point of view. By looking at the demands in home networks (DHCP, DNS etc as mentioned earlier) one at the time and investigating the features in IPv6 related to the demand, I will hopefully be able to present IPv6 in a way which is easy to follow.

Besides the IPv6 specification [5], which of course gives an in depth coverage of the protocol, the article [15], the draft [11], and the book [9] gave me a good overview over IPv6. Especially C. Huitema’s book suits my needs perfectly with sections covering addressing, autoconfiguration, security, real-time support, and transition issues.

An overview of IPv6 was also presented in my old book from the Telesystem course, [13]. One downside with this description though is the fact that the IPv6 specification was revised after the book was published. The most apparent difference is the header structure which has changed (the new 8 bit class field supersedes the 4 bit priority, and the flow field is reduced from 24 to 20 bits).

Addressing

One of the most important and factors when considering the new Internet protocol was the addressing issue. Based on elementary arithmetic the IPv4 address space would be exhausted sometime by the year 2015 with today’s trend. If every home is to have a local network, an enormous amount of addresses will be needed to assign each node with an globally unique address. With IPv6 the addressing problem doesn’t exist because of the huge address space which IPv6 provides. This is described in [7], [8] and [9].

Another aspect of addressing is the assignment of addresses and the DNS service, which has to be updated.

Autoconfiguration

In [9] C. Huitema dedicates a whole chapter to what he calls "Plug and Play". In this chapter the new autoconfiguration mechanisms in IPv6 such as stateless and stateful autoconfiguration and neighbor discovery are covered. Autoconfiguration is a very important feature, especially when considering home networks with many connected nodes which may be mobile together with the non-technical average users. I will have to focus on this section in my final report to cover all possible aspects and scenarios.

Probably I will need additional source material on this topic.

Security

Security is a frequently discussed feature of IPv6. It will also be important to be able to provide users with the insurance that only authorized users will be able to access their private home network. Without going into details about security algorithms, key exchange and so forth, I intend to give an overview of the security features built into IPv6 such as the Authentication Header (AH) and the Encapsulating Security Payload (ESP). Again, [9] gives a good description on IPv6 security in the chapter "Bringing Security to the Internet".

Mobility

In the future an average user will surely be more mobile than today. With a portable computer, or even an IPv6-enabled cellular phone, a user should be able to access the network without bothering about addressing or which physical network he is really using. This scenario relies on a working autoconfiguration mechanism, but also functionality to keep the connection to the network while moving and the ability to keep a static address. IPv6 has incorporated much from Mobile IP in this field which I will look into, just to point out the future needs for mobility in home networks. Maybe future electronic home devices will not need wiring at all, but relies solely on wireless communications?

Up till now, I have only come across the mobility issues in [9], but probably I will search for more material on this.

Real-time support

With every home connected to the Internet, the Internet will probably be the dominant distribution channel for all kinds of information. Today’s multiple services such as cable TV, radio and telephony will most likely be integrated into a single Internet access in the future. But if the Internet is supposed to deliver broadcast quality video and CD quality audio, all in real-time and together with "ordinary" Internet traffic, the Internet Protocol must have the ability to distinguish between different sorts of traffic.

In [9] C. Huitema describes the support for real-time traffic in IPv6. The new fields in the header, Class and Flow Label, together provide functionality such as priority control, hierarchical transmission and resource reservation using the Resource Reservation Protocol (RSVP).

Implementation

Transition

In this section, guidelines for how to introduce IPv6 in the IPv4 world [1] will be presented for some different scenarios. Hopefully the result will be in the form of easily understandable step-by-step instructions.

Transitioning from IPv4 to IPv6 is a extensive task and to help, IETF has put together the Next Generation Transition Workgroup (NGTRANS-WG). They have produced many informative Internet drafts and RFCs, which may come in handy. First there are informative documents such as [1], [6] and [12], which proposes different solutions for different scenarios. Then there are more technical documents describing different transition mechanisms such as AIIH [2], 6 to 4 [3], 6 over 4 [4] and Bump in the Stack for providing IPv4 application support in the IPv6 world [14].

Experimental Setup

As I probably will setup my own experimental network running IPv6, I will examine and evaluate some existing IPv6 implementations available today. To mention a few there are already IPv6 support available for Linux (kernel 2.2) and Windows NT (with Microsoft Research’s IPv6 stack). My intention is not to make my own IPv6 implementation, but rather to combine existing ones into a working network solution.

 

References

  1. W. Biemolt, M. Kaat, R. van der Pol, H.Steenman, "A Guide to the Introduction of IPv6 in the IPv4 World", draft-ietf-ngtrans-introduction-to-ipv6-transition-00.txt (work in progress).
  2. J. Bound, "Assignment of IPv4 Global Addresses to IPv6 Hosts (AIIH)", draft-ietf-ngtrans-assgn-ipv4-addrs-01.txt (work in progress).
  3. B. Carpenter, K. Moore, "Connection of IPv6 Domains via IPv4 Clouds without Explicit Tunnels", draft-ietf-ngtrans-6to4-02.txt (work in progress).
  4. B. Carpenter, C. Jung, "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels", RFC 2529, March 1999.
  5. S. Deering, R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998.
  6. R. E. Gilligan, E. Nordmark, "Transition Mechanisms for IPv6 Hosts and Routers", draft-ietf-ngtrans-mech-04.txt (work in progress).
  7. R. HindenS. Deering"IP Version 6 Addressing Architecture"RFC 2373July 1998.
  8. R.Hinden, M. O’Dell, S. Deering, "An IPv6 Aggregatable Global Unicast Address Format", RFC 2374, July 1998.
  9. C. Huitema, "IPv6, The New Internet Protocol", Second edition, Prentice-Hall 1998.
  10. C. Karlsson, "RFI: Residential Gateway", Telia Research AB, October 1998.
  11. S. King, R. Fax, D. Haskin, W. Ling, T. Meehan, R. Fink, C. E. Perkins, "The Case for IPv6", draft-ietf-iab-case-for-ipv6-04.txt (work in progress).
  12. T. Larder, "Transition Scenarios and Solutions", draft-ietf-ngtrans-trans-scenes-00.txt (work in progress).
  13. W. Stallings, "Data and Computer Communications", Fifth edition, Prentice-Hall 1997.
  14. K. Tsuchiya, H. Higuchi, Y. Atarashi, "Dual Stack Hosts using the "Bump-in-the-Stack" Technique", draft-ietf-ngtrans-dual-stack-hosts-00.txt (work in progress).
  15. C. Walton, "IPv6 - At the Starting Line", Netware Connection, May 1999, pp 6-1

Sidansvarig: Christer Engman [mail] [hemsida]