the head coach, Mr. VTAM (a rather large PU 5), needs to make sure everyone in his domain is
on the same page. Mr. VTAM carries with him his organizer (SSCP), which keeps track of
everybody and their skills. This requires him to have a session (LU 2.0) with every ballplayer
on the team (the PU 2s). This task of having these daily sessions has been wearing heavily on
Mr. VTAM, so he decides to offload some of his processing to the assistant coach, NCP (PU 4-
FEP). The assistant coach decides to pass Mr. VTAM's game plan on to the quarterback (still a
PU 2.0 but now a cluster controller). We might want to call him a clusterback. He will control
all the sessions in the huddle and will pass the assistant coach's information to the players. All
the players still have a session with the PU 5, but they do not have to bother the head coach
anymore. Keep in mind that all the players might be in session with Mr. VTAM, but they have
no sessions with and cannot talk to each other. For the players to be able to communicate with
other without Mr. VTAM's knowledge is called Advanced Peer-to-Peer Networking (APPN),
discussed in the next chapter.
resources, as shown in Figure 12-14.
Link 2