 them with SET, SET OF or CHOICE in case the list is a list of properties. A list of different kinds of properties, e.g. the property address: address SET {streetName, streetNumber, city, country} SET OF A set of the same kind of property, e.g.: firstNames SET OF firstName CHOICE A selection of properties. For example, assume you want to allow two ways to identify a set of presidential candidates (presCand): by firstName or by lastName. Assuming there are just three candidates, you would write as follows: presCand CHOICE {firstName {"Thomas", "Nelson", "Mahatma"}, lastName {"Muth", "Mandela", "Gandhi"}} This word is used to denote the optional existence of a property. For example, assume that you want to state that the property "quality of service data" (qosData) does not necessarily have to comprise a priority property. You would then write: qosData SET {bitTransp, priority OPT} But if you change your mind, you could say that if a priority value is not available, you will assume that priority is notNeeded. You would then write as follows: qosData SET {bitTransp, priority {notNeeded, needed} DEF notNeeded} The range symbol. Within the brackets you write a logical expression of values. Examples: (a) - the value a (0..100) - any value from 0 to 100 (a or b or c) - the value a or b or C (not (a or b)) - any value but a or b (0<..) - any value greater than 0 (not 0..100) - any value but values from 0 to 100 This is the key word for "internal initiating events". With this word you declare which value range of which property shall trigger an internal initiating event in the object that provides the service. Assume, e.g. that you want the object to take some recovery action in case hardware fault occurs. In the property specification you would declare the property faultState as faultState {isOk, congestion, hwFault IIE} which implies that when the service object notices that faultState has changed to hwFault, it will spontaneously take some specific action. Fig. 7.21 Notations for property specifications In the resource