Internet Protocol Forum

Contents:

From the Editor
DNS Caching
IEEE 802.21
Book Review
Fragments
 

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After many years of using DSL as my only Internet access option from home, I recently upgraded to a broadband solution provided by a cable modem. As a result, I faced the task of renumbering (and partially rewiring) my home network. As you might have guessed, the addressing scheme provided by my new ISP offers Network Address Translation (NAT), as well as a small number (5) of fixed IPv4 addresses, the latter at an extra cost as you might expect. I probably should have tried to enable IPv6 just as an experiment, but this task will have to wait for another day. In the meantime, I was pleased to find a relatively user-friendly web interface to the cable modem that allows me to configure numerous parameters, including the range of the Dynamic Host Configuration Protocol (DHCP) pool so that certain devices (printers and wireless access points in particular) can have fixed IP addresses for ease of use and configuration. The entire exercise, which took a couple of hours on my very small network, reminded me of what network managers face every day, particularly as they consider the inevitable migration to IPv6. Let me take this opportunity to invite you to share your network management and operations experience, plans for IPv6 migration, and so on. You can send us Letters to the Editor or article proposals. The address, as always, is ipj@cisco.com

The Domain Name System (DNS) has been the target of attacks over its many years of existence. In recent years, new attacks have emerged that exploit some of the attributes of the DNS protocol and its implementation. One of the corrective measures is to improve the security of DNS caches. There are several ways to improve cache security, most of which involve changing the protocol. Another way, without changing the protocol, is to reduce the attack surface of your cache by shrinking the number of users of any given cache. Our first article, by Bill Manning, explores this view in more detail.

This journal has covered numerous current and emerging wireless technologies such as Bluetooth, Wi-Fi, WiMAX, and mobile cellular systems. In this issue, Esa Piri and Kostas Pentikousis describe Media-Independent Handovers (MIH), which allow mobile devices to use different wireless and wired network infrastructures transparently. The protocols associated with operation across such diverse access networks are being standardized by the IEEE 802.21 working group.

by Bill Manning

The Domain Name System (DNS) specification calls for the use of caching. Caching is expected to improve the overall responsiveness of the system by ensuring that answers to questions are known and stored locally and that the query load placed on the authoritative servers is minimized. Certain presumptions are associated with caches that may no longer hold. This article looks at some of these presumptions and explores some of the problems that emerge when they are violated. Based on our observations, we offer some recommendations on DNS cache best practices and show our results of testing these practices.

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by Esa Piri and Kostas Pentikousis, VTT Technical Research Centre of Finland

Popular mobile devices now ship with several integrated wired and wireless network interfaces. Personal Digital Assistants (PDAs) and smartphones, for example, are increasingly supporting communications through both cellular technologies and Wireless LANs (WLANs); laptops typically come with built-in Ethernet, Wi-Fi, and Bluetooth [1]. As multiaccess devices proliferate, we move closer to a network environment that is often referred to as “beyond 3G” (B3G). Key success factors for cellular third-generation (3G) communications include better cell capacities, increased data rates, transparent mobility within large geographical areas, and global reachability. For B3G, the next frontier lies beyond transparent mobile connections within the same access technology because users will expect to be globally reachable anytime, anywhere, and remain “always best-connected” (ABC) [2]. In order to select the best possible connectivity option (anytime, anywhere), mobile devices and access networks will have to work together in order to enable users to take full advantage of all available options.

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Geeks Bearing Gifts

Geeks Bearing Gifts v1.1: How the computer world got this way, by Ted Nelson, ISBN: 978-0-578-00438-9, Published by Mindful Press, 2009, distributed through Lulu.Com, http://www.lulu.com

In a short but interesting book, computer pioneer Ted Nelson takes a very broad look at the origins and evolution of many of the basic ideas that underpin today’s computer industry. The emphasis is on concepts and technologies rather than the success of individuals, the companies they founded, and the shape of the computer industry. This approach differentiates the book from other accounts, such as Robert X. Cringley’s Accidental Empires and Martin Campbell-Kelly’s From Airline Reservations to Sonic the Hedgehog.

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RIPE Announces IPv6 Website
Four-byte AS numbers from APNIC
Please Tell Us When You Move
Call for Papers

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