makes sense to me.
What you want is dynamic lan scoped service discovery, rather than centralised registries for internet scope binding. I have been prototyping something to do this in my limited spare time; a multicast IP based system with -a variant of SLP for locating services. It will use XML, though at the current stage I just serialize a java object -an add in to axis that serves up all registered soap services on the webapp. -a client to find services by name There is no central registry at all; things just ask for all implementations of service:foo and get back a list of URLs; if they set the time to live of the packet they can ask the lan or the site. If you ask 5 minutes later, you get back a different list. I will stick this in the proposal corner of axis in a week or two, under the name of 'mir': multicast endpoint resolution. I want to get up to using XML payloads in the datagrams first; serialized objects are quick and dirty for prototyping but too unstable/unportable. -steve ----- Original Message ----- From: "Supriyo Chatterjea" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, July 09, 2002 9:44 AM Subject: Web services on a wireless adhoc network > Hi, > > I'm trying to implement web services on a wireless > adhoc network. I've given a brief overview of the > problem and the tools I'm planning to use and that's > followed by a couple of questions. > > Consider a few wireless devices within range of each > other each providing its own service(s). Each device > maintains a sort of registry that keeps track of all > the services that are being offered by all the devices > in the adhoc network at a certain instant, e.g. if a > network consists of devices A, B, C and D, device A's > registry lists the services provided by itself *and* > the services of devices B, C and D. > > If a new device E enters the network, a service > discovery algorithm ensures that A, B, C, D and E all > have their own registries updated to indicate the > services offered by all the devices in the adhoc > network. it is not clear you need to do this; the rate of change in a dynamic WLAN means that you might as well ask for services on demand. > > So basically, > > (i) every device acts as a service provider *and* a > service requester (client & server) OK > > (ii) every device has it's own private registry that > lists its own services *and* the services of the other > devices in the network not needed > Another point is that these services aren't exactly > services being offered by businesses. It could apply > to the following scenario, e.g. you receive an email > on your PDA and would like to print it out. However, > there isn't any printer available. Some time later, > you happen to walk into a room where a printer is > available. Your PDA detects the printer and asks you > if you would like to print out your email. not a problem. > So I'm talking about services like printing, > displaying some output on a screen, etc., not services > offered by businesses. And by the way these devices > are embedded devices. > > Now I'm thinking of using Jakarta Tomcat for the web > server and Apache Axis for the SOAP engine. > > Do you think that's an ok choice? The alternative is Jini, which was designed for this kind of thing. > > Does anyone have any idea how I should go about > implementing the registry? like I said, what registry? Use multicast or broadcast discovery and you dont need the central registry
