MobiCom'96 Demonstration Session

CyberGuide, Georgia Tech
Agent Tcl, Dartmouth College
Mobile-ATM, NEC C&C Research Laboratories
Wireless LAN Testbed, NEC Corporation
Monarch, Carnegie Mellon University
Rover, MIT
Dataman, Rutgers University
Mobile IP with InfraRed, IBM
Daedalus, University of California at Berkeley
WebExpress, IBM Corporation
Caubweb, The Open Group Research Institute
Welcome to the Mobility Age, FTP Software

The CyberGuide project focuses on how portable computers can assist in exploring physical spaces and cyberspaces. We are developing handheld intelligent tour guides to demonstrate future computing environments.

A mobile agent is an executing program that can migrate under its own control from machine to machine in a heterogeneous network. Agent Tcl is a simple but flexible mobile-agent system that is based around the Tcl scripting language. In this exhibit, we present the architecture of the Agent Tcl system, particularly its security mechanisms and its support for mobile computing, as well as several distributed applications in which Agent Tcl is being used.

The core idea is to use a common (ATM) network infrastructure with mobility support, and overlay protocol X atop it to obtain mobile-X (e.g. X = {IP, Telephony,.....})

Our model of mobility allows for both ATM and non-ATM access (eg Wavelan, cellular) on the wireless segment. Presently, the demo uses UDP/IP-over-Wavelan on the wireless segment, with the "base-stations" converting AAL5 data received from the (wired) ATM link to UDP/IP on the wireless segment.

We are also working on IP support over Mobile-ATM, and hopefully be able to show end-to-end IP during MobiCom'96: this should demonstrate that by running IP over Mobile.ATM, the functionality of Mobile-IP is obtained for free, i.e. mobility extensions to IP are unnecessary (when running IP over a mobile-ATM "cloud").

This demonstration gives a solution for a seamless network platform which brings flexible network connectivity into mobile computing world. Areas being studied include future communication architecture, IP mobility support, flexibly accessible radio with low power RF device, programmable modem and software oriented MAC technologies. We demonstrate a developed our testbed system. Performance of the testbed system is 25Mbps wireless modem including IP mobility support within two PCMCIA cards size.

The Mobile IP protocol described in RFC 2002 allows arbitrary unmodified IP hosts to transparently communicate with mobile hosts -- even as those hosts move and change their point of connection to the Internet between different IP subnets. We will demonstrate hosts running our implementation of the Mobile IP protocol communicating while moving between several different networks.

The Rover toolkit combines relocatable dynamic objects and queued remote procedure calls to provide unique services for "roving" mobile applications. A relocatable dynamic object is an object with a well-defined interface that can be dynamically loaded into a client computer from a server computer (or vice versa) to reduce client-server communication requirements. Queued remote procedure call is a communication system that permits applications to continue to make non-blocking remote procedure call requests even when a host is disconnected, with requests and responses being exchanged upon network reconnection. The challenges of mobile environments include intermittent connectivity, limited bandwidth, and channel-use optimization. Experimental results from a Rover-based mail reader, calendar program, and two non-blocking versions of World-Wide Web browsers show that Rover's services are a good match to these challenges. The Rover toolkit also offers advantages for workstation applications by providing a uniform distributed object architecture for code shipping, object caching, and asynchronous object invocation.

You want to get a file only if it costs < $1 but you want to get the file anyway if it is from your boss! You want to send traffic reports to specific segments on the highway, you want to advertize to people driving near a shopping mall. How do you do all this? Come see a demonstration of protocols that adapt to network availability and protocols that can route messages to specific geographic locations

Within the Internet Engineering Task Force (IETF) there are a number of development activities for protocols which are relevant to mobile networking. Included among them are mobile-IP, DHCP, PPP, mobile-IPv6, and the Service Location Protocol. This demo will showcase mobile-IP.

When mobile computers attach themselves to new networks within the Internet, they can use mobile-IP as a means to achieve seamless roaming -- transparently to application software. Applications work just as before, without need to be recompiled or reconfigured. Roaming from one place to another occurs without inconvenience to the user; as long as a physical path exists for data to be communicated, the user might not even be aware when a cell boundary has been crossed.

Using mobile-IP's simple registration protocol, a mobile client supplies information to a router, called its home agent. For communications with all other Internet nodes, the mobile client uses the same IP address as it moves from place to place. The problem of enabling mobility for an IP node is thus translated into the problem of allowing a home agent to determine the care-of address of the mobile node, which remains accessible to the global Internet by its unchanging destination address. The home agent delivers data to the mobile client at its current location by a tunneling mechanism.

Wireless Overlay Networks allow a mobile client to roam across multiple wireless infrastructures while always exploiting the best-quality connectivity in its current environment. The Daedalus project at U.C. Berkeley is exploring the management of such overlay networks as well as applications that adapt to changes in the quality of network connectivity. We will demonstrate low latency "Vertical Handoffs" across heterogeneous overlay networks. We will also demonstrate a WWW proxy that uses handoff notifications and datatype-specific content distillation to reduce user-perceived end-to-end latency.

We will demonstrate the WebExpress system by accessing several applications from an IBM Thinkpad client using a Web browser communicating over a wireless (RAM Mobile, Ardis, or CDPD link) connection (assuming sufficient signal).

WebExpress reduces data volume and latency of wireless communications by intercepting the HTTP data stream and performing various optimizations including: file caching, forms differencing, protocol reduction, and the elimination of redundant HTTP header transmission. More details on the WebExpress technology are found in the paper on WebExpress experiment results. presented in this conference.

The Distributed Clients project at the Open Group Research Institute is addressing the overall goal of supporting ongoing user access to Web-based information resources in the face of uncertain network connectivity and variations in bandwidth availability. We will demonstrate a step along that path: platform-portable software, called Caubweb, that enables users to create caches of hypertext information webs that can be accessed even while disconnected. Caubweb can also act as a pro-active caching engine for connected users by predictively retrieving and caching information, so that users can continue to browse "weblets" even after unexpected loss of network connection.

As the PC presence in the workplace grows, the amount of data which needs to be shared among the individuals of any company is also on the rise. Yet with the time constraints placed on any busy employee, it becomes necessary for data sharing to be done while the employee is involved in other activities, hence the need to transport laptops from place to place both within a domain, and off site, while data is being exchanged. Enter Mobile IP.

This demo will illustrate the exchange of data while subnet transitions are made. This can be voluntary, or, as the number of wireless network connections increases, based purely on which wireless bridge the strongest signals eminate.

In our commitment for full multiple vendor interoperability (based on RFC2002), FTP Software invites other vendors to join our network simultaneously, and test their mobile nodes with our mobility agents, their mobiltiy agents with our mobile nodes, and their mobility agents with our mobility agents.