Currently the Internet has only one level of name resolution, DNS, which converts user-level domain names into IP addresses. In this paper we borrow liberally from the literature to argue that there should be three levels of name resolution: from user-level descriptors to service identifiers; from service identifiers to endpoint identifiers; and from endpoint identifiers to IP addresses. These additional levels of naming and resolution (1) allow services and data to be first class Internet objects and (2) facilitate mobility and provide an elegant way to integrate middleboxes into the Internet architecture. We further argue that flat names are a natural choice for the service and endpoint identifiers. Hence, this architecture requires scalable resolution of flat names, a capability that distributed hash tables (DHTs) can provide.

The Web relies on the Domain Name System (DNS) to resolve the hostname portion of URLs into IP addresses. This marriage-of-convenience enabled the Web's meteoric rise, but the resulting entanglement is now hindering both infrastructures---the Web is overly constrained by the limitations of DNS, and DNS is unduly burdened by the demands of the Web. There has been much commentary on this sad state-of-affairs, but dissolving the illfated union between DNS and the Web requires a new way to resolve Web references. To this end, this paper describes the design and implementation of Semantic Free Referencing (SFR), a reference resolution infrastructure based on distributed hash tables (DHTs).

The Internet provides a large-scale environment for (intelligent) software agents. Agents are autonomous (mobile) processes, capable of communication with other agents, interaction with the world, and adaptation to changes in their environment. Current approaches to support agents are not geared for large-scale settings. The near future holds thousands of agents, hosts, messages, and migratory movements of agents. These large-scale aspects require a new approach to facilitate the development of agent applications and support. AgentScape is a scalable agent-based distributed system described in this paper that aims at tackling these aspects.

The Domain Name System (DNS) is a critical part of the Internet’s infrastructure, and is one of the few examples of a robust, highlyscalable, and operational distributed system. Although a few studies have been devoted to characterizing its properties, such as its workload and the stability of the top-level servers, many key components of DNS have not yet been examined. Based on large-scale measurements taken from servers in a large content distribution network, we present a detailed study of key characteristics of the DNS infrastructure, such as load distribution, availability, and deployment patterns of DNS servers. Our analysis includes both local DNS servers and servers in the authoritative hierarchy. We find that (1) the vast majority of users use a small fraction of deployed name servers, (2) the availability of most name servers is high, and (3) there exists a larger degree of diversity in local DNS server deployment and usage than for authoritative servers. Furthermore, we use our DNS measurements to draw conclusions about federated infrastructures in general. We evaluate and discuss the impact of federated deployment models on future systems, such as Distributed

In order to achieve better scalability and reduce latency in handling user requests, many Web applications make extensive use of data replication through caches and Content Delivery Networks. However, in such scenarios data is often placed on untrusted hosts. As a result, existing replication mechanisms open a wide class vulnerabilities, ranging from denial of service to content masquerading. In this paper we present an architecture that combines data content, replication strategies and security in one unified object model and offers integrity guarantees for Web documents replicated on non secure servers. 1

and implementation of a secure wide-area object middleware

The Internet provides a large-scale environment for (intelligent) software agents. Agents are autonomous (mobile) processes, capable of communication with other agents, interaction with the world, and adaptation to changes in their environment. Current approaches to support agents are not geared for large-scale settings. The near future holds thousands of agents, hosts, messages, and migratory movements of agents. These large-scale aspects require a new approach to facilitate the development of agent applications and support. AgentScape is a scalable agent-based distributed system described in this paper that aims at tackling these aspects.

The Web relies on the Domain Name System (DNS) to resolve the hostname portion of URLs into IP addresses. This marriage-of-convenience enabled the Web’s meteoric rise, but the resulting entanglement is now hindering both infrastructures—the Web is overly constrained by the limitations of DNS, and DNS is unduly burdened by the demands of the Web. There has been much commentary on this sad state-of-affairs, but dissolving the illfated union between DNS and the Web requires a new way to resolve Web references. To this end, this paper describes the design and implementation of Semantic Free Referencing (SFR), a reference resolution infrastructure based on distributed hash tables (DHTs). 1