The basic principles of the original Internet architecture included end-to-end addressing, global routeability, and a single namespace of IP addresses that could serve simultaneously as locators and host identifiers. A second namespace of fully qualified domain names was later added, and a domain name system (DNS) was developed to map between such names and addresses. Additionally, over time, a number of additional namespaces have emerged, many of which include some component of domain names and are also served by DNS. DNS has used caching to scale well, and consequently is not optimized for rapid updating of records.

However, due to the growing trend towards mobility of users, terminals or even whole networks, dynamic naming structures are gradually replacing the static mechanisms of the traditional Inter-net. Meanwhile, the emergence of network address translation (NAT) has clouded the end-to-end significance of IP addresses. Moreover, during the evolution of the Internet from a small re-search network to a worldwide information exchange, a growing diversity of commercial, social, ethnic, and governmental interests has led to increasingly conflicting requirements among the competing stakeholders. These conflicts create tensions that the original Internet architecture struggles to withstand. Clark et al. refer to this development as “tussles in cyberspace”

This evolution has prompted research into different internetwork-ing architectures, such as FARA, Plutarch, Triad, i3, SNF, TurfNet, DOA, IPNL and 4+4, among others. At the core of these next-generation network architectures are naming and addressing frameworks that are significantly more flexible, expressive, and comprehensive than the Internet’s hierarchical IP address space. These naming frameworks are key components that enable ad-vanced internetworking capabilities, such as multi-homed mobil-ity, dynamic composition of networks, or delay and disruption-tolerant communication.

The naming architectures of these new internetworking architec-tures frequently have a more formal framework for naming than do current networks. Many naming architectures provide dynamic bindings between the levels of names and objects. With dynamic bindings at multiple levels, names of objects can become location independent and support different types of mobility, e.g., nodes or services. Some naming architectures also support the notion of indirection or delegation.

To discuss these issues and to advance this field of research, a seminar on naming and addressing for next generation internet-works was held at the Schloß Dagstuhl from October 29 to November 1, 2006 . Researchers from different fields discussed their views and recent results pertaining to naming and addressing problems related to the seminar topic. This article briefly reviews their presentations and discussions, as well as the research questions identified and debated at the seminar.

The seminar brought together a diverse community of researchers from academia and industry, with different research interests in-cluding network theory, mobile networks, interdomain routing, networking in challenging environments, privacy, deployment, and peer-to-peer aspects of networking.

The contributions and discussions echoed many similar concepts during the workshop, including cryptographic names, flat names, search as a naming mechanism, DTNs, DHTs, etc. Hence, an im-portant question is: “Are we all working on similar things and is the packaging and terminology an issue?” It appears that a com-monly accepted terminology is missing for naming and address-ing. There have been several attempts to define a common termi-nology for addressing and naming, but the results of the workshop suggest that those approaches are not sufficient and more general evaluation of the terminology problems is needed. To start with, a clear problem description for naming and addressing issues would help. For example, it is not clear whether the problems are more about performance and efficiency or about providing new capa-bilities. Furthermore, additional research has to evaluate which features and characteristics the current APIs are missing that hin-der users from offering services with more flexible naming.

Part of the problem with naming seems to be the lack of hard requirements, stemming, among others, from a fuzzy understanding of the naming and addressing infrastructure users. Hence, there is a clear need to better define the problem space and resulting requirements. Questions like “what is being named?”, “what are connectivity properties of the network?”, “what must it inter-operate with?”, “what are the service models?”, and “what infra-structure is needed?” have to be addressed. Participants would also like to see boundaries and tradeoffs in a more analytical and rigorous manner, taking aspects like security, heterogeneity, and mobility into account.

But where are the specific problems in generalizing naming or in finding axiomatic approaches to naming? Routing seems to be one problem, as it is hard to separate from naming and addressing. Furthermore, there are three different groups of stakeholders – operators, terminals and users/services – and it seems to be hard to find a common ground between them. A general understanding of the specific problems is still missing, though. Mobility is a good example; it is an intensively studied aspect in the context of naming and addressing. Yet, it is not clear if the lack of a clear solution for IP mobility is a result of the architecture or a fundamental problem with mobility.

With respect to some of the perceived fundamental problems, there are nevertheless some promising, but not fully tested solutions, such as HIP. Hence, future work should focus more on deployment and implementation to gain more experience with those solutions.

Moreover, short-lived labels and multiple coexisting namespaces are promising areas that should be further investigated. If name-spaces are added to the current architecture, implications on the search, resolution, security, and routing mechanisms have to be considered, resulting in additional engineering and operating costs that have to be taken into account as well.

Current approaches place lots of focus on the network layer. The strong impact that Google and search engines in general have had on the way that people think about names and networking APIs implies that we may need to be more radical in thinking beyond the network layer.

Participants agreed that a follow-up workshop in about 18 months to discuss those topics and other advances would be useful.