Kannel WAP and SMS Gateway 1.4.1 review

Kannel WAP and SMS Gateway project is a WAP and SMS gateway. SMS, short message services, are widely used all over the world in hu

License: BSD License File size: 2535K Developer: The Kannel Group

0

Kannel WAP and SMS Gateway project is a WAP and SMS gateway.

SMS, short message services, are widely used all over the world in huge amounts. The main use for Kannel is to link HTTP based services to various SMS centers using obscure protocols.

WAP, short for Wireless Application Protocol, is a collection of languages and tools and an infrastructure for implementing services for mobile phones. Traditionally such services have worked via normal phone calls or short textual messages (e.g., SMS messages in GSM networks). Neither are very efficient to use, nor very user friendly. WAP makes it possible to implement services similar to the World Wide Web.

Unlike marketers claim, WAP does not bring the existing content of the Internet directly to the phone. There are too many technical and other problems for this to ever work properly. The main problem is that Internet content is mainly in the form of HTML pages, and they are written in such a way as to require fast connections, fast processors, large memories, big screens, audio output, and may require fairly efficient input mechanisms. That's OK, since they hopefully work better for traditional computers and networks that way. However, portable phones have very slow processors, very little memory, abysmal and intermittent bandwidth, little screens and extremely awkward input mechanisms. Most existing HTML pages simply will not work on them.

WAP defines a completely new markup language, the Wireless Markup Language (WML), which is simpler and much more strictly defined than HTML. It also defines a scripting language, WMLScript, which all browsers are required to support. To make things even simpler for the phones, it even defines its own bitmap format (Wireless Bitmap, or WBMP).

HTTP is also too inefficient for wireless use. By using a semantically equivalent, but binary and compressed format it is possible to reduce the protocol overhead to a few bytes per request, instead of up to hundreds of bytes. Thus, WAP defines a new protocol stack to be used. However, to make things simpler also for the people actually implementing the services, WAP introduces a gateway between the phones and the servers providing content to the phones.

The WAP gateway talks to the phone using the WAP protocol stack, and translates the requests it receives to normal HTTP. Thus, the content providers can use any HTTP servers, and can utilize existing know-how about HTTP service implementation and administration.

In addition to protocol translations, the gateway also compresses the WML pages into a more compact form, to save bandwidth on the air and to further reduce the phone's processing requirements. It also compiles WMLScript programs into a byte-code format.

Requierments:
C compiler and development libraries and related tools.
The gnome-xml (a.k.a. libxml) library, version 2.2.0 or newer. We recommend that you use libxml version 2.2.5. If you are installing it from your distribution's packages, you'll need libxml2-dev in addition to run-time libxml2 package libraries.
Note: there is a bug in libxml version 2.2.3 and 2.2.4 that causes problems with character encoding in attributes. This problem is fixed in 2.2.5. See http://xmlsoft.org/xml.html.
GNU Make.
POSIX threads (pthread.h).
GNU Bison 1.28 if you modify the WMLScript compiler.
DocBook markup language tools (jade, jadetex, DocBook style-sheets, etc; see README.docbook), if you want to format the documentation (pre-formatted versions are available).

What's New in This Release:
Various critical bugfixes since 1.4.0, including major SMSC protocols supported (SMPP, EMI/UCP, and GSM AT modem comands), HTTP layer fixes, and WAP WTP and WTP SAR layer fixes.
The sendsms HTTP interface has been improved to obey the bearerbox message state for replies.