Transactions versus transaction units and TPS

In SS7 signaling, a transaction is typically defined as one MSU transmitted and one MSU received, and assumes a worst-case scenario of that many MSUs both transmitted and received simultaneously per second.

IP signaling capacity is not usually constrained by the IP network (bandwidth), but rather by the processing platform (CPU or memory). The cost of a given transaction varies based upon the feature set triggered by the transaction. Not all MSUs are the same, and not all configurations are the same. Rather than to continue to engineer product capacity for the worst case and thereby penalizing customers who are not using worst-case scenarios, Oracle is providing the Transaction Unit (TU) model to allow customers flexibility in how to use application or card capacity.

Under the TU model, a transaction unit indicates the relative cost of an IP signaling transaction; the base transaction unit is 1.0. Some transactions are more expensive than others in terms of IP signaling card capacity. A transaction that is less expensive than the base has a transaction unit less than 1.0, and a transaction that is more expensive is greater than 1.0. The total transaction units consumed by an MSU are the sum of the base transaction unit value and the additional transaction unit value. Transaction Units per Second (TPS) are then calculated with the total transaction unit value and the Advertised Card capacity.

For detailed information on how to calculate IP signaling TPS and the number of cards required to carry MSU traffic, see How to calculate transaction units per second (TPS) and Calculate the Number of Cards Required.