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326 STANDARDS ANDPROTOCOLS INDATACOMMUNICATIONSas rlogin are available, and command shells such as rsh
simplify access. More recently a secure shell known as
SSH has become available. This ensures encryption is
used to protect networks from hackers when logging on.The World Wide Web (HTTP, HTML)
The original data transfer method for network use was
FTP; however, with the advent of the WWW and the hyper-
text transfer protocol (HTTP), a different approach was
possible. Now users could specify content for provision via
a Web server as pages rather than files of material. HTTP
therefore only needs to transfer the content of the page
into the local Web browser for viewing. In this sense it is
a one-way device, whereas FTP allows the file to be trans-
ferred, modified, and returned. Hypertext markup lan-
guage (HTML) is the document-structuring language used
by content creators on the WWW to create Web pages. It is
a tag-structured language; although not strictly compliant
as a subset of SGML, it is similar in concept.The Next Generation (XML, SOAP, .NET)
The W3C is actively developing new features and ser-
vices for the WWW, several of which are subsets of the
SGML standard. Using HTML the content provider has
restrictions on how they control their pages, which are
set by HTML itself. Using the extensible markup lan-
guage (XML) users can create their own tags. XML al-
lows the definition, transmission, and interpretation of
these data between applications. The proposed standard
simple object access protocol (SOAP) was developed by
Microsoft in conjunction with other software vendors as
a way of adding document object models (DOMs) to stan-
dard HTTP streams. This effectively violates the purpose
and intent of firewalls. Currently Microsoft is offering an
OS known as .NET, which is specifically designed to op-
erate as a distributed Web-based operating system. This
will lead to the concept of paying for use of software as re-
quired since it will be downloaded from the relevant Web
site on demand.Emerging Multimedia Protocol Standards
Multimedia is now a common application format across
all Internet-enabled devices; however, the needs of such
data combinations of graphics, text, audio, and video are
different from those historically associated with the Net.
For an excellent introduction to the subject the reader is
referred to Halsall (2001). Some of these needs are the
following:The audio and video must meet deadlines or defined
time intervals or the user will experience indeterminate
delays.
Variation in timings (jitter) must be bounded to avoid
large buffers being needed to smooth the flow of data.
Multicast is a requirement for cooperative work and video
conferencing.
Mechanisms are needed for synchronizing different data
streams.
A current standard that addresses the needs of audio is
known as MIDI.The MHEG (Multimedia and Hypermedia Information
Coding Expert Group) are one of several working groups
of the ISO currently looking at standards for multimedia
application use. The ISO/IEC JTC1/SC29 committee (Cod-
ing of Audio, Picture, Multimedia, and Hypermedia In-
formation) carries overall responsibility for three working
groups: WG1 Coding of Still Pictures (JBIG/JPEG), WG11
Coding of Moving Pictures and Associated Audio (MPEG),
and WG12 Coding of Multimedia and Hypermedia Infor-
mation (MHEG). Both the MPEG (Motion Picture Expert
Group) and the JPEG (Joint Photographic Expert Group)
are of particular importance to the multimedia world and
the future of automated content costing for e-commerce
use.E-COMMERCE ENABLING PROTOCOLS
SSL/TLS and HTTP
Transactions over the Web for e-commerce require com-
plete security if customer confidence is to be maintained.
Without the assurance that others will not be able to ac-
cess account details no potential e-commerce transaction
will take place. Little can be done to stop certain types of
fraud such as the nonexistence of goods for sale but the
network transaction itself must be seen as secure. Several
schemes exist but the secure socket layer (SSL) protocol,
which lies in the session layer of the OSI model, provides
authentication services for the client or the server. Full
details of these services can be found in another chapter.
All e-commerce transactions require the transfer of
documents of some kind. This implies that not only the
content but also the structure should be exchanged. It is
reasonable to require these structures, or document ar-
chitectures, be the same at both ends of the network con-
nection, hence the need for standards. The two current
popular standards are the SGML and the open document
architecture (ODA). A well-known application standard
from typesetting is postscript. These document control
systems have become increasingly important with the ad-
vent of the WWW and multimedia applications, and have
coined the terms hypermedia and hypertext due to their
abstract manner of access. The exchange format for mul-
timedia is MHEG. Different task forces are working on
the standards for hypermedia; amongst these are ISO/IEC
JTC1 SC2/WG12 MHEG for coded representations of
multimedia and hypermedia, the ANSI X2V1.8M for
the Music Information Processing Committee, and the
Standard Music Description Language (SMDL).
SGML (ISO 887) is a tag-based system, which means
the standard specifies the form of the tags but user groups
determine their position and meaning. The most famous
application is HTML, which is understood across the
WWW.Emerging Mobile E-commerce Protocols
The ubiquitous use of mobile phones has provided the
opportunity for Internet-based e-commerce applications
to grow as an independent market area. Traditionally the
main content for the telephone companies was voice;
however, this has changed to data. A similar change is oc-
curring with mobile traffic. Initially almost entirely voice,