sap的数据交换接口有三种： ALE application link enabling,RFC remoting funcation call 和CPI-C Common Programming Interface Communications 。它们之间的关系如下图：

-----------------------------
　                 |           ALE                   |
                      -----------------------------
        ---------------------------------------------
         |                RFC                                 |
         --------------------------------------------
  --------------------------------------------------------
  |                    CPI-C                                           |
  ---------------------------------------------------------
ALE是架构在RFC和IDOC技术上来完成数据通信交换.
RFC是架构在CPI-C接口之上，RFC的调用都将转换为CPI-C的调用完成.
CPI-C是数据交换的最基本接口,他使用复杂,一般情况不用,它只有在以下特殊情况下才被采用:

客户的系统平台不支持RFC
旧系统必须使用CPI-C作通信接口
系统需要复杂的通信协议

相关TCODE:

SM59 : 配置通讯
SM58: 察看RFC的LUW
SMQ1:Monitor RFC Queue
SARFC:Monitor RFC Resources on the Application Server
SMQR:
SMQS:
SMQ1:
SMQ2:

相关表:

RFCDEC:为远程功能调用的目的表
 ARFCSSTATE and ARFCSDATA
TRFCQOUT  and TRFCQIN

相关package: SRFC
几个重要的样例:

RSTRFCT0, RSTRFCT1, RSTRFCT2, and RSTRFCT3 are sample or test programs for qRFC with send queue. 相关函数:

• RSTRFCQ1, RSTRFCQ2, RSTRFCQ3, and RSTRFCQ4 you can stop processing one or more queues, continue processing with or without condition, or query the status of a queue.

START_OF_BACKGROUNDTAST:
TRFC_SET_QUEUE_NAME
TRFC_SET_QUEUE_RECEIVER_LIST (inbound queue)
TRFC_SET_QUEUE_NAME_LIST (outbound queue)

用户权限对象: S_RFC