Communication Model

Portals combine the characteristics of both one-side and two-sided communication. They define a "matching put" operation and a "matching get" operation. The destination of a put (or send) is not an explicit address; instead, each message contains a set of match bits that allow the receiver to determine where incoming messages should be placed. This flexibility allows Portals to support both traditional one-sided operations and two-sided send/receive operations.

Portals allows the target to determine whether incoming messages are acceptable. A target process can choose to accept message operations from any specific process or can choose to ignore message operations from any specific process.