Hi Francesco, My original suggestion was to use DNS to identify the URL of the UDDI server in the local subnet. The advantage to this is that no broadcast message is needed and it's using a common solution. The disadvantage is it requires an entry in the DNS server database, some knowledge of how to administrate it, and isn't automated.
So, I tend to agree with Eric's solution (except for the last step which I believe should be unicast, not broadcast). The basic idea is to have the client broadcast a "who has a UDDI Server" message when it comes online. XML will be ok, because since the broadcast only happens once, verbosity is not an issue. However, a simple text message would also do the trick and eliminates the need to parse XML. In either case, a simple UDP server process listening on over a known port on the UDDI server machine will respond, identifying itself to the client. At that point the IP address of the UDDI server is available to the client and the UDDI request can be unicast to it. This message sequence is identical the ARP protocol, which allows an end-host to determine the MAC address of system with a known IP address. The end-host broadcasts a "who has this IP address?" message to the subnet. If a host with that IP address receives the message, it unicasts an "I have it" message, enclosing its MAC address along with it. From then on, all communication for that flow can be unicast. The actual messaging discussed above should be handled outside of SOAP, since SOAP is not intended for this kind of functionality. It could be easily implemented as with Java using UDP datagram sockets. This approach handles the potential problem of multiple servers on the same subnet, since the client can just choose one. It also solves the problem of the UDDI server not being architected around a possible broadcast scenario, typically running over TCP. You won't need SOAP over UDP. It minimizes network overhead since only a single broadcast is made, when the client comes online. Regards, Mark -----Original Message----- From: Eric VERGNAUD [mailto:[EMAIL PROTECTED] Sent: Tuesday, May 31, 2005 7:58 AM To: [email protected] Subject: Re: SOAP-over-UDP It depends on what you mean by continuous. a 16 bytes packet every 5 seconds certainly won't. If you need a higher reactivity, you can do the following: - have the client broadcast a message on a port - have the server listen on that port - when the server receives a connection, have it broadcast as suggested in my previous email Le 31 mai 05 � 13:17, Francesco Munari a �crit : > But there isn't the risk of flooding the LAN with these continuous > broadcast messages? > > 2005/5/31, Eric VERGNAUD <[EMAIL PROTECTED]>: > >> Have your server regularly broadcast its address on a port. >> Have your client act as a server on startup and listen on the same >> port. >> When the real server broadcasts its address, the client will receive >> a connection request. >> One you have the server address, ask the server for the information >> you need (what you call the context). >> >> Le 31 mai 05 � 11:41, Francesco Munari a �crit : >> >> >>> Hi, Eric. >>> >>> Ok, but how can I do this? I think I'm a newbie in this kind of >>> operation, sorry. How can I look to a port of servers in a LAN >>> without >>> knowing their IP? And in this way may I keep the context- >>> awareness of >>> the communication? >>> >>> thank you for you reply >>> >>> Cheers >>> >>> francesco >>> >>> 2005/5/31, Eric VERGNAUD <[EMAIL PROTECTED]>: >>> >>> >>>> I'm afraid that is a very verbose way of doing things. The typical >>>> way to do this is determine a port, have your server broadcast >>>> its IP >>>> address on that port, and your clients look on that port to grab >>>> the >>>> address. >>>> >>>> Once the address is found, you can safely interact with the server >>>> using SOAP over HTTP. >>>> >>>> Le 30 mai 05 � 22:19, Francesco Munari a �crit : >>>> >>>> >>>> >>>>> I'm alredy using UDDI4j. The idea is that I don't know where the >>>>> UDDI >>>>> registry can be in the LAN. >>>>> I assume that the client knows only two things: >>>>> 1) the network (of course) >>>>> 2) a "search key" for a particular tipe of service >>>>> >>>>> and that's all. >>>>> The client should send a broadcast SOAP (or XML-RPC) request >>>>> containing the search method to call on the server with the "key" >>>>> passed as a parameter and somewhere into the LAN should be a >>>>> server >>>>> (or more) with its private UDDI registry that should reply with a >>>>> response containing the result of the invoking of the method >>>>> contained >>>>> in the sender's RPC request. The response should contain just the >>>>> URL >>>>> of the WSDL file related to the service found. >>>>> >>>>> The need of the broadcast message is that the client don't know >>>>> where >>>>> (or if) there could be any UDDI registry in the network. With this >>>>> framework a client can change network configuration (for example, >>>>> going from a floor to another with a Palm in a wireless LAN) and, >>>>> after leaving the service provided in the first network, find >>>>> anothe >>>>> one similar on the other network only by pressing the button >>>>> "Refresh" >>>>> :) >>>>> >>>>> Francesco >>>>> >>>>> 2005/5/30, Martin Gainty <[EMAIL PROTECTED]>: >>>>> >>>>> >>>>> >>>>>> The side effect of a broadcast without authentication is >>>>>> flooding the >>>>>> network with unwanted disovery packets >>>>>> I guess this is OK if you're utilising a high datarate >>>>>> transmission i guess >>>>>> >>>>>> In your case your SOAP Request should look like >>>>>> >>>>>> <?xml version="1.0"?> >>>>>> <SOAP-ENV:Envelope >>>>>> xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"; > >>>>>> <SOAP-ENV:Body> >>>>>> <getTest> >>>>>> <Test>Test</Test> >>>>>> </getTest> >>>>>> </SOAP-ENV:Body> >>>>>> </SOAP-ENV:Envelope> >>>>>> >>>>>> If you want to discover a "SOAP based" web-service based on some >>>>>> characteristic such as Business Service Category why not use >>>>>> UDDI4J? >>>>>> Take a look at >>>>>> http://sourceforge.net/projects/uddi4j >>>>>> >>>>>> Martin- >>>>>> >>>>>> ----- Original Message ----- >>>>>> From: "Francesco Munari" <[EMAIL PROTECTED]> >>>>>> To: "Martin Gainty" <[EMAIL PROTECTED]> >>>>>> Cc: <[email protected]> >>>>>> Sent: Monday, May 30, 2005 12:44 PM >>>>>> Subject: Re: SOAP-over-UDP >>>>>> >>>>>> Martins, >>>>>> >>>>>> It is for this reason that I'd like to broadcast a SOAP request >>>>>> instead of a simple XML-RPC message. The goal of my framework >>>>>> is to >>>>>> keep the "context awareness" offered by XML language. >>>>>> If you are sure that there is no way to send a broadcast SOAP >>>>>> request, >>>>>> the last solution, I think, it could be XML-RPC. >>>>>> >>>>>> So, two questions: >>>>>> >>>>>> 1) are you sure ther's no way to send a broadcast SOAP request? >>>>>> 2) In order to send a broadcast XML-RPC message I've to cerate a >>>>>> StringWriter like this (for example)? >>>>>> >>>>>> <?xml version="1.0" ?> >>>>>> <methodCall> >>>>>> <methodName>getTest</methodName> >>>>>> <params> >>>>>> <param> >>>>>> <value> >>>>>> <string>Test</string> >>>>>> </value> >>>>>> </param> >>>>>> </params> >>>>>> </methodCall> >>>>>> >>>>>> Thank's Martin. >>>>>> >>>>>> Francesco >>>>>> >>>>>> 2005/5/30, Martin Gainty <[EMAIL PROTECTED]>: >>>>>> >>>>>> >>>>>> >>>>>>> Francesco- >>>>>>> You can Broadcast XML-RPC assuming you dont mind flooding your >>>>>>> network >>>>>>> The question is can you confine your application to using the >>>>>>> more basic >>>>>>> datatypes supported by XML-RPC >>>>>>> vs implementing SOAP features (user-defined datatypes, namespace >>>>>>> URI)? >>>>>>> Anyone else? >>>>>>> Martin- >>>>>>> ----- Original Message ----- >>>>>>> From: "Francesco Munari" <[EMAIL PROTECTED]> >>>>>>> To: "Martin Gainty" <[EMAIL PROTECTED]> >>>>>>> Cc: <[email protected]> >>>>>>> Sent: Monday, May 30, 2005 6:45 AM >>>>>>> Subject: Re: SOAP-over-UDP >>>>>>> >>>>>>> Grazie! :) >>>>>>> >>>>>>> Could someone tell me if a simple XML-RPC message may be sent >>>>>>> to a >>>>>>> broadcast address? A simple message with the medthod to be >>>>>>> invoked. In >>>>>>> this way I should be able to send a broadcast XML-RPC request >>>>>>> with the >>>>>>> appropriate UDDI inquiry method; a server (containing a UDDI >>>>>>> registry) >>>>>>> should receive it, invoke that method and send a reply in XML >>>>>>> format >>>>>>> to the sender. >>>>>>> >>>>>>> It could be a good idea? >>>>>>> >>>>>>> thank you again! >>>>>>> >>>>>>> Francesco >>>>>>> >>>>>>> 2005/5/29, Martin Gainty <[EMAIL PROTECTED]>: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> benvenuto! >>>>>>>> Martin- >>>>>>>> >>>>>>>> ----- Original Message ----- >>>>>>>> From: "Francesco Munari" <[EMAIL PROTECTED]> >>>>>>>> To: <[email protected]> >>>>>>>> Sent: Saturday, May 28, 2005 5:41 PM >>>>>>>> Subject: Re: SOAP-over-UDP >>>>>>>> >>>>>>>> Thank you all for your very quick reply! >>>>>>>> >>>>>>>> I've heard about this SOAP-over-UDP spec >>>>>>>> (http://msdn.microsoft.com/library/default.asp?url=/library/en- >>>>>>>> us/dnglobspec/html/soap-over-udp.asp). >>>>>>>> So, Martin, you say that it could not be a solution? Perhaps it >>>>>>>> should >>>>>>>> be an idea using Mark's solution (with DNS). >>>>>>>> >>>>>>>> I thought to resolve the problem putting a SOAP envelope into >>>>>>>> a UDP >>>>>>>> datagram, send the datagram to a broadcast ip and that's all >>>>>>>> folks...but I don't know how and, as you, Martins, wrote, I >>>>>>>> was not >>>>>>>> able to find anybody who has implemented this yet. >>>>>>>> >>>>>>>> Can you suggest me another solutions? >>>>>>>> >>>>>>>> Thank you very much again!! >>>>>>>> >>>>>>>> Cheers, >>>>>>>> >>>>>>>> Francesco >>>>>>>> >>>>>>>> 2005/5/28, Martin Gainty <[EMAIL PROTECTED]>: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> Mark/Francesco >>>>>>>>> I would caution on use of UDP as the SOAP Portocols (e.g. >>>>>>>>> HTTP) >>>>>>>>> is/are >>>>>>>>> decidely not UDP but instead a connection-oriented TCP >>>>>>>>> To date I have not seen UDP Ports used for SOAP transmission >>>>>>>>> although >>>>>>>>> since >>>>>>>>> there is no requirement for verifiable connection and or >>>>>>>>> handshakes >>>>>>>>> I would venture to guess UDP is available as the transmission >>>>>>>>> medium >>>>>>>>> but >>>>>>>>> I >>>>>>>>> have not seen any UDP Ports used for SOAP thus far >>>>>>>>> Anyone else ??? >>>>>>>>> Ciao- >>>>>>>>> Martin- >>>>>>>>> >>>>>>>>> ----- Original Message ----- >>>>>>>>> From: "mdonaghue" <[EMAIL PROTECTED]> >>>>>>>>> To: <[email protected]>; "'Francesco Munari'" >>>>>>>>> <[EMAIL PROTECTED]> >>>>>>>>> Sent: Saturday, May 28, 2005 3:14 PM >>>>>>>>> Subject: RE: SOAP-over-UDP >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>>> Hi Franceso, >>>>>>>>>> >>>>>>>>>> I've worked briefly with the apache soap api, not that >>>>>>>>>> familiar with >>>>>>>>>> it. >>>>>>>>>> Typically a soap message is sent to a single soap server >>>>>>>>>> address, >>>>>>>>>> which >>>>>>>>>> is >>>>>>>>>> specified by a url or an ip address, as well as a port. So >>>>>>>>>> your >>>>>>>>>> server >>>>>>>>>> address on the LAN might be something like >>>>>>>>>> 192.168.100.2:8080. >>>>>>>>>> (I'm >>>>>>>>>> not >>>>>>>>>> sure >>>>>>>>>> what the port is for UDDI, so just using standard TomCat Web >>>>>>>>>> Server >>>>>>>>>> port). >>>>>>>>>> >>>>>>>>>> IIRC, you there's a point at which you specify that >>>>>>>>>> address in >>>>>>>>>> the >>>>>>>>>> setup >>>>>>>>>> for >>>>>>>>>> your soap call. One thing you could try is to change the >>>>>>>>>> address to >>>>>>>>>> the >>>>>>>>>> subnet's broadcast address, 255.255.255.0:8080, assuming a >>>>>>>>>> class c >>>>>>>>>> network >>>>>>>>>> where the first 3 quads specify the network portion of the >>>>>>>>>> submask. >>>>>>>>>> >>>>>>>>>> However, this may not a scalable solution, since the >>>>>>>>>> broadcast >>>>>>>>>> wouldn't >>>>>>>>>> carry beyond the physical subnet on which you are located. >>>>>>>>>> Using >>>>>>>>>> UDDI >>>>>>>>>> to >>>>>>>>>> discover services is one thing, but dynamically discovering >>>>>>>>>> UDDI >>>>>>>>>> servers >>>>>>>>>> is >>>>>>>>>> obviously a different problem. It also doesn't address the >>>>>>>>>> issue of >>>>>>>>>> more >>>>>>>>>> than one UDDI server running on the same subnet. >>>>>>>>>> >>>>>>>>>> A more generalized solution might involve a distributed ip >>>>>>>>>> lookup >>>>>>>>>> service, >>>>>>>>>> namely DNS. For example when DNS looks up the ip address of >>>>>>>>>> Yahoo.com, >>>>>>>>>> at >>>>>>>>>> some point the actual ip address that serves the request is >>>>>>>>>> dynamically >>>>>>>>>> assigned to one of dozens (or hundreds) of servers based on a >>>>>>>>>> scheduling >>>>>>>>>> scheme. You could locally enable DNS lookup, and create an >>>>>>>>>> entry >>>>>>>>>> based >>>>>>>>>> on >>>>>>>>>> some url like "myuddpsever.com", and give it your local UDDI >>>>>>>>>> server's >>>>>>>>>> ip >>>>>>>>>> address, and the rest would be handled within the network. >>>>>>>>>> The >>>>>>>>>> advantage >>>>>>>>>> to >>>>>>>>>> this is your UDDP server could be anywhere and your message >>>>>>>>>> would >>>>>>>>>> still >>>>>>>>>> reach it. >>>>>>>>>> >>>>>>>>>> hth, >>>>>>>>>> Mark >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -----Original Message----- >>>>>>>>>> From: Francesco Munari [mailto:[EMAIL PROTECTED] >>>>>>>>>> Sent: Saturday, May 28, 2005 4:58 AM >>>>>>>>>> To: [email protected] >>>>>>>>>> Subject: SOAP-over-UDP >>>>>>>>>> >>>>>>>>>> Hi, I'm desperate! >>>>>>>>>> I'm trying to find out how to send a broadcast SOAP request >>>>>>>>>> to a >>>>>>>>>> UDDI >>>>>>>>>> registry in a LAN, but I'm not able to do this. I've looked >>>>>>>>>> for some >>>>>>>>>> example but I've not found anithing. >>>>>>>>>> >>>>>>>>>> Please...could anybody help me? >>>>>>>>>> I'm making a thesis for the University of Florence (Italy) >>>>>>>>>> and I >>>>>>>>>> have >>>>>>>>>> to discovery dinamically web service published in some UDDI >>>>>>>>>> registry >>>>>>>>>> somewhere in a LAN. I have to send a broadcast SOAP >>>>>>>>>> request to >>>>>>>>>> these >>>>>>>>>> UDDI registry (as I wrote few lines above). >>>>>>>>>> Of course I'm using Java language. >>>>>>>>>> >>>>>>>>>> Thank you very much for your help...I'm in a great >>>>>>>>>> hurry...thanks >>>>>>>>>> very >>>>>>>>>> very much to everyone could help me! >>>>>>>>>> >>>>>>>>>> Best reguards, >>>>>>>>>> >>>>>>>>>> Francesco >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> >>> >> >> >
