1 Background

1. A Globe name server based on BIND8, which resolves a Globe URN into a location-independent object handle (OH)
2. A Globe location server, written entirely in Java, that resolves an OH into one or more contact addresses for the identified Globe object
3. A proxy that can bind to an object given a contact address, and which interfaces to existing Web browsers, by translating Globe URNs into equivalent URLS. The proxy is also written in Java.

SIRS-1 has originally been proposed as consisting of two phases. Development in phase 1 concentrates on client software, including the name server, location server, and the proxy. Phase 1 is scheduled to finish by 01.12.1999. For phase 1, the following activities remain to be done:

1. Extending the location server with persistence, so that contact addresses can be stored on disk.
2. Testing, the client software by configuring a number of local Web pages as Globe Web documents, and which are accessible through our current client software (installed at the VU).

All client software will be made available by 01.12.1999 to a number of sites. The sites are yet to be selected.

Phase 2, from now on referred to as SIRS-2, concentrates on the development of server software, and the development of a serious application demonstrating the feasibility of the Globe approach.

SIRS-2 is divided into two subprojects. Subproject SIRS/Server deals with developing server software. SIRS/GDN (Globe Distribution Network) concentrates on development of a network for the distribution of files, in particular freeware and shareware.

2 Subproject SIRS/Server

We have already started the process of designing a generic Globe server, capable of supporting Globe Web documents and Globe distributed shared objects in general. A collection of Globe servers will form a Globe virtual network for physically distributing Globe objects. The development of the Globe server is in accordance to the original SIRS-1 project plan. The main difference is that we plan to deliver prototype versions earlier. Planned dates and activities are as follows:

Subproject SIRS/Server requires an estimated effort of I FTE. Details concerning this subproject can be found in the original project proposal for SIRS-1.

3 Subproject SIRS/GDN: The Globe Distribution Network

In addition to the development of the Globe server, we propose to develop software that will allow Globe to be used for the (worldwide) distribution of files, in particular freeware and shareware.

3.1 Overview

As an application of a Globe virtual network, we propose to develop a network consisting of Globe servers configured to support a worldwide infrastructure for distributing software (and other resources). This Globe Distribution Network (GDN) will have the following properties:

• Resources can be replicated as needed, where each resource can have a specific replication strategy attached to it; there is no need to have a single global strategy that is applied to all resources. For example, some software may be mature and effectively read only. Other software may be experimental and undergo frequent updates. Different strategies may be used for them.
• Resources will be secured in the sense that updates can be done only be authorized people, such as the owner. This requires the development of a security infrastructure.
• Resources can be anything that fits into a file. Initially, we concentrate on supporting software distributions, including the accompanying documentation, which may include text, images, etc.

The development of the Globe Distribution Network (GDN) should be done in parallel to the development of the Globe server in SIRS/Server. In particular, as soon as the design of the Globe server has finished, we will have insight in what specific tools we need to set up and maintain GDN. For example, we will need to tools to monitor and set-up servers, make it easy to add, remove, and update resources, etc.

3.2 Details

Within SIRS/Server we design and develop a generic Globe server capable of handling distributed shared objects. To demonstrate the feasibility of our approach, SIRS/GDN concentrates on using the Globe software for implementing an overlay network to support distributions of freeware and shareware. To that end, we need to develop a number of tools that support the following functions:

1. Listing files stored in the GDN
2. Searching for specific files
3. Downloading a selected file
4. Adding, a file to the GDN
5. Removing a file

Operations are permitted by authorized users only. In particular, adding a file to the GDN requires special security measures. In addition, the GDN should be capable of handling "traditional" malicious attacks. To simplify security issues, we initially assume the GDN servers operate behind a firewall.

The GDN will logically consist of two different parts. The first part consists of the actual files that are stored in GDN. Each group of files (i.e., that make up a distribution package) is implemented as a simple Globe distributed shared object. The simplicity comes from the object's interface, which allows a user only to fetch the contents of a file to store it locally. However, each distribution package can have its own replication strategy associated with it.

The second part of the GDN handles naming and locating distribution packages. It consists of a name space implementation which maps user-readable names into object handles. This name space implementation is the one developed in SIRS-1. In addition, a location service returns the address of each replica of the referred file. Again, this is the same implementation as partly developed in SIRS-1.

The GDN will initially be implemented throuoh a limited number of sites (5-15), where each site runs a GDN server. To simplify matters, each site also runs a complete version of the name space implementation. This means that the name space is replicated on each GDN site. A simple update protocol will be used to add names. The location server is distributed across the GDN sites by means of a distributed search tree.

To build GDN, the following components and tools are needed:

• System administration tools that help set up a new GDN server, and remove or replace a server.
• System administration tools to configure the naming and location services.
• A component to register authorized users, and to handle authentication.
• An application (implemented partly as a Globe distributed object) that allows authorized users to add to, and remove files from the GDN.
• An application (implemented partly as a Globe distributed object) that assists the user to search for a software package.

When a user has selected a distribution package, it can be downloaded in its entirety, or per file. Details on the actual downloading need to be filled in. A possible scenario is the following:

1. A client uses a standard Web browser, possibly cooperating with the SIRS client software to handle Globe URNS, to access the Globe Distribution Network.
2. A client binds to a Globe directory object, allowing, it to list and select other directory objects, or distribution packages. Selection of another object implies that the client binds to that object.
3. When a client has selected, and is bound to, a distribution package, it is offered a (possibly dynamically generated) HTML page to download the files. Each file appears as a hyperlink, implemented as an FTP URL pointing to the file on the specific GDN server to which the client is connected.
4. The GDN server is colocated with an FTP server on the same machine. Downloading, files is completely handled through the FTP server.

This approach has the benefit that GDN is used only to handle per-package distribution requirements, simplifying its initial design and implementation. Existing protocols and software can be used to handle the actual transfer of packages to the client.

3.3 Plan of Work

SIRS/GDN can start on 01.12.1999. The following activities have been planned, and to be completed at the mentioned dates:

Subproject SIRS/GDN requires the estimated effort of 1 FTE.

4 Summary

The two subprojects are closely related to each other. SIRS/Server concentrates on the core development efforts of a Globe server capable of supporting distributed shared objects. SIRS/GDN concentrates on the development of tools and actual set-up of a distribution network, based on the Globe server. There are a number of joint deliverable dates:

The software developed and running on 01.12.2000 will be made publicly available as source code to stimulate further developments by other parties, unless the VU and NLnet foundation decide otherwise.

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