Link level security

Link level security refers to those security services that are invoked, directly or indirectly, by an MCA, the communications subsystem, or a combination of the two working together. This is illustrated in Figure 1.

Figure 1. Link level security and application level security
This diagram shows that link level security services are invoked, directly or indirectly, by an MCA, the communications subsystem, or a combination of the two working together. Application level security services, by comparison, are invoked at the interface between an application and a queue manager to which it is connected. The diagram also shows that application level security can protect messages while they are being stored on queues.

Here are some examples of link level security services: