Introduction

Figure 3-4 on page 58 and Figure 3-5 on page 59 should be viewed as two halves of one large illustration. This split illustration is referenced heavily in the following discussions. Note that many of the elements in the illustration are tagged with reference letters for ease of reference in the discussions that follow. Also keep in mind that, while there are several types of QPs, the split figure and the examples in this section describe message passing as it occurs on one type of QP (referred to as the Reliable Connected, or RC, type).