Why SAP Web disptacher is needed ?

[former_member686510]

When an ABAP(ICM) system can serve the HTTP/S requests , why there is a need for a Web dispatcher ? Can some one explain ?

[Former Member · Accepted solution]

Hello Shankar,

If I keep it simple.....

Imagine you have a system with multiple application servers:

app01.myco.com

app02.myco.com

app03.myco.com

app04.myco.com

Each of these application servers can handle HTTP/HTTPS requests.

1. Users may create bookmarks in their browser that point to maybe app01 or app02. We don't want them to do that.

If app01 or app02 was down one day, your helpdesk may be flooded with calls from users who are trying to access your system with their bookmark app01.myco.com , app02.myco.com.

2. Security. We don't want people knowing the names of our servers.

3. Load Balancing between available application servers is easier.

4. Maintenance is easier.

Imagine you retire app01.myco.com and replace it with app05.myco.com which is more powerful. This would be transparent to your user community if you have a WD.

So if your users accessed your system via a wed dispatcher (internalportal.myco.com), backend changes would be transparent to them. they can bookmark internalportal.myco.com and there will be no problems.

An additional nice functionality of the WD is that it can (up to a point) act as a reverse proxy (but that's a subject for another day).

Just think of it this way, when you access amazon.com, there are hundreds/thousands of servers behind that name. All you are interested in is amazon.com (the web dispatcher if you want to look it that way).

I hope I haven't confused you.

Kindest Regards,

Amerjit

[manumohandas82 · Accepted solution]

To Add on others  to above 

and If your query continues " Why not i use the message server"

1) Provides security as webdispatcher  is mostly installed  in DMZ (Demilitarized zone) - Most Important in case of security especially for portals

2 ) For stateful Web applications( BSP applications), you require the Web Dispatcher.

3 ) Intelligent enough for redirect urls  ( Message server cannot do redirection )

Thanks ,

Manu

[Former Member · Accepted solution]

Some additional info from SAP:

Architecture and Functions of the SAP Web Dispatcher - SAP Web Dispatcher - SAP Library

Amerjit