Since all data
requested from a content server must pass through the WAP gateway, it is very important
that the contents reaches the browser in a proper state. WAP gateways convert or compile
the textual WML code into a binary format, and this conversion process is different in
virtually every gateway. Some do it faster than others, some do it better than others. One
piece of code does not necessarily produce the same binary content. It's not uncommon to
find that one deck works fine via one gateway, while crashing via another.
The intention is to give
you as an application developer an overview of what to expect from each gateway, and maybe
even to help gateway developers get their products on the right track.
With the help of the
brilliant people of the WML and WMLscript Programmers mailing list, a detailed list of gateway
inconsistencies will be compiled.
For now, the following aspects of the WAP
gateway will be examined: (The list is guaranteed to change frequently)
- Does the gateway identify itself to the
web server?
- Does the gateway support some form of
unique ID for the device it's provisioning?
- Does the gateway support cookies according
to the HTTP specifications?
- Does the gateway support some form of
cookie?
- Does the gateway pass through any
unrecognized element/attribute to the browser as unencoded text?
- Does the gateway scramble HTTP headers?
- Does the gateway convert content and
images in some way?
- Does the gateway handle and convert
charsets to and from what the device requested?
- What is the best, average and worst
average compilation ratio?
- Is the gateway normally deployed by
network operators?
- How does the gateway handle already
compiled WMLC?
- How does the gateway handle WMLscript
compilations?
- How does the gateway handle caching?
- How does the gateway support additional
data types such as GIF, BMP, HTML etc etc?
- How does the gateway handle different
character sets?
- How well does the gateway comply with
interoperability specifications?
- Is the gateway mostly used in vertical or
horizontal applications?
- Which platforms does the gateway run on?
- Does the gateway support subscriber number
forwarding?
- Does the gateway support WTLS and SSL?
- Is the gateway also capable of serving
content?
- How much does the gateway cost?
| Phone.com UP.Link |
| Horz/Vert
application deployment |
Horizontal |
The
product is meant for, and resides at Network Operators |
| Rough
product deployment |
Developer
states 35% of Network Operators world-wide |
|
| Compliation ratios |
Not
yet tested |
|
| HTTP Gateway
Identifier |
Adds "XXX
UP.Link" to HTTP User-Agent string |
Example:
EricssonR320/R1A UP.Link/4.1.0.1 |
| Unique Client ID |
HTTP
header HTTP_X_UP_SUBNO contains subscriber number |
Note:
Must be configured for "provisioning" |
| Cookie Support |
Yes |
According to RFC2109 |
| Unrecognized
element/attribute action |
The
UP.Link gateway passes unrecognized elements and attributes through as unencoded text |
|
| Content/Image
conversions |
BMP pictures are
turned into WBMP pictures for R3 handsets. Other content is also compiled - obviously WML
into WMLc, but also HDML into HDMLc and conversion between the two. Translation between
HDML and WML for non-Phone.com browsers is on a best-efforts basis. |
An optional facility
is provided whereby HTML content can be translated on a best-effort basis. |
| Character set
conversions |
Both
to and from the client device |
|
| Precompiled WMLC
action |
Already compiled WMLC
is passed through |
|
| Caching action |
content
generally is not cached in the gateway. However, because of the time spent in HTML
translation, and the observed nature of the use of such a translator, content being
translated from HTML is cached. |
|
| Additional data
types |
BMP images, GIF
images, HTML text |
|
| Interoperability
issues |
|
|
| Platform
specifications |
Sun
Solaris + Oracle db |
|
| Subscriber number
forwarding |
Yes |
See Unique Client
ID |
| WTLS/SSL support |
Yes |
|
| Content serving
support |
Yes |
Not usually
recommended by manufacturer |
| Pricing policy |
Unknown |
Since
this is a product directed at Network Operators, it tends to be too expensive for casual
use |
|
