No need for TCP?


Recently, there is a flux of new Web Services specifications that are addressing low-level engineering needs, for example the speed of the communication, or even the network protocol. Let’s see two of them:

1) SOAP over UDP. The name is self-describing: you send SOAP messages in UDP packets. The funny thing is that an IP address is just a particular case of a more general WS-Addressing address. You can specify an IP address as source/target but also a domain name, etc. The specification is probably a good example that shows how general WS-Addressing can be. Here is an example of a UDP packet:

(001) <S:Envelope xmlns:S="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing" > 
(002) <S:Header>
(003) <wsa:To>http://fabrikam.com/Server</wsa:To>
(004) <wsa:Action>http://fabrikam.com/Probe</wsa:Action>
(005) <wsa:MessageId> uuid:1da72f1a-5546-493c-934c-a9e3577e206a </wsa:MessageId>
(006) </S:Header>
(007) <S:Body>
(008) ...
(009) </S:Body>
(010) </S:Envelope>

2) MTOM is another specification that allows pure binary data to be sent along with SOAP messages. The same idea appeared in an earlier spec (SOAP with Attachments) but MTOM pushes the concept further by considering optimizations not only at the wire level (i.e. how to efficiently serialize SOAP messages with binary data) but also on the transmission protocol itself.

Interestingly enough, Ricoh and Lexmark contributed to the first specification, while Canon contributed to the second one… I can’t wait for the first web-service enabled photo camera!

Comments (3)

  1. Ovidiu says:

    Silently waiting for the buzz to end and for things to settle down 🙂

    SOAP is ok for lots of things (I can’t wait for web services to replace current e-mail protocols, providing for better security and performance, for instance), but I don’t exactly see myself listening online radio stations via SOAP 🙂 Let’s be honest to ourselves, the "use the right tool for the job" is still valid (vs. "use the cool tool for the job").

  2. Adi Oltean says:

    >> Let’s be honest to ourselves, the "use the right tool for the job" is still valid (vs. "use the cool tool for the job").

    I completely agree!

    >>> Silently waiting for the buzz to end and for things to settle down 🙂

    On the other side, I think that we are still somewhere at the beginning of the "web services" phase. Standard implementations of WS-* protocol suite are just starting to take off… and many of these specs are still under development. Things will probably start to change when Indigo and other WS-* enterprise-level implementations will start to gain adoption.

  3. Ovidiu says:

    … And I can’t wait for WS-* to kill RPC. At least we’ll finally get rid of DCOM issues 🙂

    Regardless of that, I still don’t believe in "web services everywhere". To me, it’s best to use the simplest tool that will do the trick. OTOH I’m sure that, in time, web services will get the attention they deserve in scenarios where they’re the simplest tools.

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