easily masqueraded, making it potentially untrustworthy. Regardless,
despite the drawbacks of the UDP protocol, it is still widely in use today.
For instance, the Simple Mail Transfer Protocol (SMTP), on port 25, sup-
ports UDP, making it possible to transmit emails while impersonating the
identity of an alternate IP address.
Despite the downfalls of the UDP protocol, there are some advantages to
using it. For instance, because it lacks a binding process, the protocol saves
processing time, so a UDP packet can be quickly delivered to a client or
server process. The protocol is also available to software developers who
might use it when building custom applications, including gaming soft-
ware and data-driven, peer-to-peer, UDP-based, noncritical applications
that are built for speed but can tolerate some degree of inaccuracy. Last,
without a binding process, server-side state cannot be maintained in a UDP
transmission as it can be with the TCP/IP transmission.
SOAP-based Web service HTTP transports are built on a unique founda-
tion. In some ways, their transmission characteristics emulate the efficien-
cies associated with the UDP protocol by allowing you to call a remote Web
service only once to send the data (because the data is generally so small in
terms of bytes). In many other ways, they emulate transmissions associ-
ated with the TCP/IP protocol, allowing you to keep state if necessary and
to track return information to the user to confirm HTTP requests. Effec-
tively, it is like having the best of both worlds.
Why Web Services Are Superior to Winsock and DCOM
The following subsections discuss the history of Winsock and DCOM.
Writing a basic client/server application that leveraged TCP through the
Microsoft Winsock control was not a problem, but your efforts were dupli-
cated for each application server you wrote. Here are some additional
reasons why this was a painstaking way of accomplishing distributed
There was no standard parser.
Server code applied specifically to the client that it was built for.
Maintenance was a hassle.
Firewalls would stop you cold unless you formatted your transmis-
sion in an HTML-like format.
What Are Web Services?