Channel exit programs
Channel exit programs are programs that are called at defined places in the processing sequence of an MCA. Users and vendors can write their own channel exit programs. Some are supplied by IBM .
There are several types of channel exit program, but only four have a role in providing link level security:
- Security exit
- Message exit
- Send exit
- Receive exit
These four types of channel exit program are illustrated in Figure 1 and are described in the following topics.
- Security exit overview
Security exits normally work in pairs. They are called before messages flow and their purpose is to allow an MCA to authenticate its partner. - Message exit
Message exits operate only on message channels and normally work in pairs. A message exit can operate on the whole message and make various changes to it. - Send and receive exits
Send and receive exits typically work in pairs. They operate on transmission segments and are best used where the structure of the data they are processing is not relevant.
Parent topic: Plan confidentiality
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