Archive for the ‘T1 and E1 PRI’ Category
Progress Indicators (PIs) in ISDN Q.931
According to Bellcore and ANSI specifications, in-band progress tones and announcements are required for PSTN services and for ISDN speech and 3.1-kHz voice services. In order to guarantee that the necessary in-band tones are generated when required (and at the right switch), Cisco H.323 gateways must ensure that Progress Indicators or PIs are carried end-to-end in called signaling messages between the calling and called parties. The PI is an IE that signals when in-band tones and announcements are available. The PI is configured by the "progress_ind" command. Below is a list of PIs that can be configured on a Cisco H.323 gateway:
Configurable Progress Indicator Values for H.323 Gateways
- PI=0 No progress indicator is included. Message type: Setup
- PI=1 Call is not end-to-end ISDN; further call progress information may be available in-band. Message type: Alert, setup, progress, connect
- PI=2 Destination address is non-ISDN Message type: Alert, progress, connect
- PI=3 Origination address is non-ISDN Message type: Setup
- PI=8 In-band information or appropriate pattern is now available Message type: Alert, progress, connect
CCIE Voice Lab Exam v3.0 Topics
The blueprint is a detailed outline of the topics likely to appear on the lab exam. This blueprint introduces pre-configurations of basic tasks (such as phone registration, basic application integration, basic dial plan, etc.), in order to devote additional focus on expert level skills (advanced configuration and troubleshooting) assessments. As usual, knowledge of troubleshooting is an important skill and candidates are expected to diagnose and solve issues as part of the CCIE lab exam. The topics listed are guidelines and other relevant or related topics may also appear.
