A switching network will connect group of trunk opering (TO), as build up connection (telephone traffic) path request, to Trunk Serving (TS) or server. This TO and TS form as customer line, trunk between central or switching equipment, and if needed, also form as equipment generally to build connection.
TO that functioned to send build up connection request (telephone traffic) to switching network will shaping group TO. Meanwhile servers that receive and to forward on build up a connection is request for one route switching will shaping group TS.
One server on busy state if already happen a connection through switching networks between one TO and that server. In this case, traffic that carried by TO group will form as calls that will using one server, which one call that succeeded shaping connection (from one caller customer to called customer) will to dwell one server.
Time period which one server on busy state and cannot interrupted to do one switching job, is called Holding Time.
Complete definition of holding time is total time utilization/occupation one switching equipment by one call, start from the customer pick up telephone (hook off), or when central start (seized), until end connection (cleared) customer putdown telephone (hook on).
Switching network as conversation path network
Switching network as network connector
Figure 1.2. Simplified switching network configuration
