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In this page contains, I've included my networking notes.
Push & Pull Technology
Overview
The latest buzzwords in the web are 'Push-Pull Technology'. While one
view is that 'this will be next important wave in web technology', others are quite
skeptical about 'push' and ask Who will push "Push"?. This is quite a confusing
scenario especially for the Corporate MIS and the Software developer community. In our
evaluation this is an important wing of present day technology
�What
is Push-Pull Technology
The technology of push-pull is deceptively simple. Put in plain words
this technology facilitates relevant information to be sent to the clients automatically
without the clients having to make an effort to retrieve information.
�Pull
To request data from another program or computer. The opposite of pull
is push, where data is sent without a request being made. The terms push and pull are used
frequently to describe data sent over the Internet. The World Wide Web is based on pull
technologies, where a page isn't delivered until a browser requests it. Increasingly,
however, Information services are harnessing the Internet to broadcast information using
push technologies. A prime example is the PointCast Network.
�Benefits
of Push-Pull Technology
Users can determine what sort of information they want, and then get
that delivered directly to their desktops without having to search for information, there
by all relevant actors are informed at the appropriate time.
Content can be downloaded at anytime including idle time of the machine,
there by, saving on bandwidth. This content can be stored locally and retrieved
significantly faster than surfing the Web real time Riddance of the unnecessary clutter to
wade through tons of data before finding something useful. Information is sent across only
on a 'need-to-know' basis, which is fast and flexible.
How
Does Push Work?
How
Push is Really Automated Pull
The Web currently requires the user to poll sites for new or updated
information. This manual polling and downloading process is referred to as
"pull" technology. From a business point of view, this process provides little
information about a user, and offers little control over what information is acquired. It
is the user who has to keep track of the location of the information sites, and the user
has to remember to continuously search for informational changes--a very time consuming
process. The push model alleviates much of this tedium. Interestingly enough, from a
technical point of view, most push applications are still "pull" and just appear
to be "push" to the user. A more accurate description of this process is
automated pull. Most push applications require a subscription and an information request
profile from the user before they can begin filtering information. They also require the
client to poll the server when it is able to accept information. The software initiates
the "pull" according to a user-defined schedule (once a day, every three hours,
etc.), and the server responds with the information to match the request profile.
There are a couple of true push technology applications--one being
Wayfarer's Incisa* product. When the Incisa client is started, it opens a connection to
the Incisa server and it stays open until the client is stopped. Another true push
technology is AirMedia Live* from Air Media. This technology uses the broadcast radio
spectrum to transmit to their client applications. The client application is a combination
of a radio receiver and a software application. The radio receiver is always receiving
information from the server/transmitter.

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Figure 4: Current Environment--Pull

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Figure 5: Push as Automated Pull
So if push applications are not really push what is so different about
them? The difference is the automation of the process for both the publisher and the
subscriber.
Information
Delivery Models
There are at least three (3) information delivery models by which push
applications can be categorized. These models differ in the costs incurred for purchase
and uptime, the ease of use, the ease of integration into a publisher's existing
information delivery structure, the customization capabilities, the branding adherence,
and in other areas that a publisher should examine with regard to need.
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Figure 6: Information Delivery Models
Push
Server Model
The most common delivery model is the PUSH SERVER model. This is a
turnkey solution that provides a client, server, and development tools. Costs associated
with the server may include the number of connections and/or the number of packets sent.
Branding may or may not be an issue. A proprietary client is supplied. These applications
may use a proprietary protocol.
Web
Server Extension - CGI
A closely related model is the WEB SERVER EXTENSION model. In this
model, the push vendor does not buy a server, so the costs are associated with the number
of extensions sold. Feedback and demographic information can be directed to an external
server, so that information can be retained by the push vendor (transfer costs may need to
be negotiated separately). Installation should be less extensive since no true server is
involved. No proprietary client is required; these run within the user's regularly
installed browser.
Client
Agent Model
The final model does not need to have a server at all, except to update
client software and retain user demographics. This model uses a "client agent"
to retrieve the information from sites. Each agent is designed to provide different search
results. This model can allow for an anonymous relationship between the vendor and the
subscriber. Costs are associated with the agent customization. The user is responsible for
deployment, and controls the search type extensibility.
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This page� was last updated on the 9th
September 1998.
Copyright@ 1998 Shan.All rights reserved. |