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How MDT reduces the data traffic in communication line

 
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ganmain

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PostPosted: Wed Apr 06, 2005 1:00 pm    Post subject: How MDT reduces the data traffic in communication line
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hi,
i want to know how mdt(modified data tag) reduces the data traffic in communication line
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rick

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PostPosted: Wed Apr 06, 2005 6:59 pm    Post subject:
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hi,

Conider the case u are updating the table, u will read from the table and send it to the screen. Say u have send 10 fields. But your program is to update a single field. So in that case sending all the 10 field will need more trafffic than sending a single field. So all other 9 field the MDT is reset. So while receiving one field is received.


Thanks and Regards,
Frederick.
frederick.tybalt@anewcon.com
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ganmain

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PostPosted: Wed Apr 06, 2005 7:09 pm    Post subject: Re: doubt on mdt
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hi,

thanks for your reply

but i had one doubt
in the map(dfhmdf) if we would have given fset for all the fields ie(mdt on for all the fields) in this case how it will reduce the data traffic

please clarify this

with regards
ganesh
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rick

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PostPosted: Wed Apr 06, 2005 7:49 pm    Post subject: Re: doubt on mdt
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using FSET in all the fields will not reduce u the traffic.
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ganmain

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PostPosted: Fri Apr 08, 2005 7:04 pm    Post subject: Re: How MDT reduces the data traffic in communication line
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thanks
but i need some clarification

if we give fset in map
whether mdt will be always on whether the user entered the data or not in the screen?

only the fields with mdt on will be received in to the program
(correct or not)
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radhakrishnan82

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PostPosted: Mon Apr 11, 2005 1:56 pm    Post subject:
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If a field is changed then it means that there is a modification of that particular field.Hence,MDT for this field will be automatically set to ON.Hence this field alone will be received.

Let me give an example.I guess some of you might aware abt this very good example of MDT concept.

Consider registering a private e-mail id.It will ask for user name, passwd ,address and some info regd personal details,etc..
Now you have entered all the details.At the first time,every field was modified in this case and all were sent to the corresponding e-mail server.The information was recorded in the SMS(Storage Mgmt System).

Registration was successfull and you got ur own mail id.Now you start sending mails.The server needs your mail id field and your passwd field for identification and not all the other details such as personal, address,etc...Hence,in this case,MDT is always set ON for mail id (or username)field and passwd field.Whenever u send mails,the server receives only ur mail id(or username) and ur passwd to identify the sender.Unless you change your account information,all other details will not be sent to the server.If you have given fset in DFHMDF attribute then all the other details will also be sent to the server which causes traffic in the network(and proves that some details other than user name and passwd is unnecessary).
Its a great example of reducing the data traffic to the server and across the server.Isn't it?
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ganmain

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PostPosted: Mon Apr 11, 2005 6:07 pm    Post subject: Re: How MDT reduces the data traffic in communication line
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hi radhakrishanan,
thank u very much for explaining in detail.
but still i am having some confusion.
u have told that mentioning fset in dfhmdf field will increase the data traffic.
from your point of u
fset should me mentioned for only user name & password field.

but anyway when the user starts typing the field mdt will be on.
then what is the use of mentioning fset in this fields?

if this is the case when we have to give fset in dfhmdf field ,whwn we should not give?
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remargorp loboc

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PostPosted: Tue Apr 12, 2005 12:57 am    Post subject: Re: How MDT reduces the data traffic in communication line
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WHAT IS MDT(MODIFIED DATA TAG). Each field in a map has a attribute byte, in attribute byte, there is a bit called MDT witch is set to ON or OFF. Bits of atribute byte are assembled in compile time of mapset, but you can set attribute in execution time moving values to A-suffix dataname of a map field.

HOW IT WORKS. When you send a map, BMS data stream is prepared with the proper attributes in fields. the attribute of a field afect the way field is presented or receive back. If a field has MDT BIT set to ON, in receive you will allways get back the value of field. If a field has a MDT BIT set to OFF, you only will get back the value of field if user change the value of this field.

HOW IT REDUCES TRAFFIC. If all fields have MDT ON, full data is allways received back. if all fields have MDT OFF. Only modified data is received back.

TRICK. If you want do save some information in a map, but don't want to show it to users, you can set attribute to X'7D'(ASKIP,DARK,MDT ON)

More information in CICS PROGRAMING GUIDE.

remargorp loboc
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radhakrishnan82

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PostPosted: Tue Apr 12, 2005 2:17 pm    Post subject:
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Quote:
fset should me mentioned for only user name & password field.

but anyway when the user starts typing the field mdt will be on.
then what is the use of mentioning fset in this fields?

if this is the case when we have to give fset in dfhmdf field ,whwn we should not give?


ganmain,

fset should me mentioned for only user name & password field
For this case,fset should have been set for username and passwd field.If someother field is also required then we can set ON the MDT flag on that particular field.

when the user starts typing the field mdt will be on.
Absolutely correct.Whenever a field is modified its set to ON.

use of mentioning fset in this fields
Let me explain you with the same example.
You are composing an email.You login ur mail account thru your user name and passwd and the server identifies you by the same.You enter mail id's in the To Address field.Hence "To address" field is modified and this field was sent to the server.

From Address is necessary for identification whoever receives a mail.
But you don't type From Address.Even there may not be "From address" field.In this case,this field was always set ON using fset on the corresponding field parameters.

do you understand now,why fset is required in some fields though MDT turns on when there is a modification in that field.

if this is the case when we have to give fset in dfhmdf field ,whwn we should not give?
For example,In profile info,the address details consists of lot of details.door no.,street name.,area,city,state.country.But all combination of the above forms a complete address of a person.All the details are stored as ADDRESS DETAILS in SMS.

Suppose there is a condition even if any one of the address fields are modified then whole address details(complete address) should be sent to the server.For this case,fset can be given in dfh parameter.if this condition is not required then avoid using fset in dfh for this case.

Normally fset is used for mandatory details.You might have come across * on one field and ** on double field while registering applications.
** may have the meaning in the map as "Its mandatory but it will be sent to the server though it is unchanged".
* may have the meaning in thr map as "Its mandatory but it will not be sent to the server unless it is changed".

This is just an example.
There may be lot of real time scenarios using the process.
try to find & list out those areas and let us know icon_smile.gif.
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ganmain

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PostPosted: Tue Apr 12, 2005 3:38 pm    Post subject: Re: How MDT reduces the data traffic in communication line
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hi,
thank u very much for your reply

now i understood clearly.

with regards
ganesh.s
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