As colors do not work well on monochrome printers, their value in the notation
was limited to computer use: inspecting models in the modeling tool or generated
documentation.
5.4 MODELING IP TELEPHONY SERVICES
5.4.1 Example Model
The structure of the CPL language maps closely to its behavior so that a service
developer who understands the domain concepts can also understand and validate
the service from the graphical models. Figure 5.7 illustrates the speci?¬?cation of a
MODELING IP TELEPHONY SERVICES 111
service: here, all incoming calls originating from ???example.com??? are redirected to the
address ???sip: jones@example.com,??? and if there is no answer, a line is busy, or a
failure occurs, the call is redirected to the voice mail address ???sip: jones@voicemail.
example.com.??? All calls that originate from addresses other than example.com will be
redirected immediately to the same voice mail.
5.4.2 Use Scenarios
The DSM solution was made to support the reuse of services as a subaction (see
Fig. 5.5, model layering). In Fig. 5.8, the same subaction is reused as in Fig. 5.7. In this
case, the user attempts to have his calls reach his desk; if he does not answer within 8
second, calls from his boss are forwarded to his mobile phone, and all other calls are
directed to voicemail. If the call setup fails, the failed call information is stored in the
log and sent to the email address.
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