Alv ports

Question

hi to all abap gurus
my querry is
what are the diffrenr type   of ports available in in tcode  we21.
  plss  expalin abt the diffrent types of ports . what are the file port sand what are the xml ports  pls give direct ansers points will berewarded.

Answer 1

Ports are a fundamental requirement for communicating by means of the the IDoc interface. At least one port must exist for each external system.
Port type      Application area
File Interface or file port      Link to most EDI subsystems
Transactional RFC      ALE distribution scenarios
CPI-C      Link to R/2 System: Direct communication with an R/2 System (from version 5.0F onwards) is only possible via this port type.
Internet      Sending to e-mail addresses,used to connect with internet applications.
Programming Interface (PI) or ABAP ports     The IDoc is not exchanged with an external system but rather with a function module you have written. This means that any dispatch type can be used.to process data via the abap programming interface.
XML      Used to process files in XML format.
File interface or file port
Definition
Exchange of IDocs and status records via operating system files
Process flow
The sending system writes a file in the file system. Then it notifies the receiving system via the synchronous RFC,
     • that the file has been transferred,
     • where the file is located (directory) and
     • what the file is called (file name).
So that no data is lost, the sending system never attaches other data to a file that has already been transferred to the receiving system. The receiving system processes the transferred files completely. It is then automatically deleted from the file system.
Transactional RFC :
It is an asynchronous communication process,meaning that when an idoc is dispatched, The sender does not wait for the idoc to be received on the destination system. Control returns as soon as the idoc is successfully transferred to the communication layer. The IDOC gets a status code of  03 if it is successful. The communication layer must make sure that the idoc is successfully transferred to the destination system.
Port Type CPI-C:
Port type for direct access to an R/2 System via the CPI-C protocol.
The R/3 System logs on to the R/2 System to send or retrieve IDocs. The necessary logon data is maintained in the R/3 System under an RFC destination. The target system (R/2) and the technical communication attributes are maintained in the table TXCOM.
Port Type Internet :
Definition
Conversion of IDocs from or into e-mails.
Use
IDocs can be exchanged via the Internet with any system which has an e-mail address.
The Internet address of the partner is stored in the port definition. As the Business Workplace is used here, you can specify the Workplace folder which stores the IDoc mails to be sent as Workplace documents.
ABAP Programming Interface (PI) :
Definition
The exchange of IDocs between the ABAP function modules.
Use
The R/3 System is the “external system” in which further processing can be programmed. Thus, you can for example program your own techniques for transfer to an external system.
Port Definition
You only have to enter the name of the function module to be called (for IDoc outbound processing) or the calling ABAP function module (for IDoc inbound processing). This function module can be programmed to contain the required processing. Only the interface is already defined.
Port Type XML :
Definition
The exchange of IDocs via XML files at the operating system level. The names of XML tags refer to the IDoc record types or IDoc segments.
Use
XML is designed to be a self-descriptive Internet-enabled language. In contrast to HTML, tags can be defined here and recorded in a Document Type Definition. As a result, XML is extendible and corresponds in particular to the new definition of IDoc types concept. IDocs in XML format can be displayed immediately with the corresponding Internet browser. Electronic Commerce in particular uses XML, but classical EDI applications should also be XML compatible.