Dialogue

This is an important pattern especially in network trace analysis. It usually involves a message source, a different message target (although both can be the same) and some alternation between them as shown on this abstract trace diagram:

Message and source are not only IP addresses or port numbers. They can be window handles, for example. Sometimes, the roles of source and target play different Process ID and Thread ID combinations (Client ID, CID). In such cases some parts of a message text may signify reply and response as shown graphically:

The similar illustration can be done for multi-computer trace, for example, when several traces from different servers are combined into one, where a combination of CID and a computer ID (Co) or just CO can play the roles of source and target.

Note that on all illustrations above the 3rd request doesn't have a reply message: a possible Incomplete History (Volume 5, page 286) pattern.