The combinational circuits employ the comparators for comparing the numbers and storing them on the basis of maximum and minimum functions. Likewise in the interconnection networks the two processors carry out the computation of maximum and minimum functions in the given way below: 

Let's consider that there are 2 processors p_i and p_j. Every one of these processors has been given as input an element of sequence say e_i and e_j. Now the processor p_i transmits the element e_i to p_j and subsequently processor pj sends e_j to p_i. Afterwards processor p_i computes the minimum of e_i and e_j it implies that min (e_i,e_j) and processor p_j computes the maximum of e_i and e_j, it implies that max (e_i,e_j). The above process is known as compare-exchange and it has been depicted in Figure.

Figure: Illustration of Exchange-cum-Comparison in interconnection networks