The following SIP applications provide functionality to originate an announcement as an RTP stream.
SrpSipApp- N2SRP Specialised Resource Platform
LhoSipApp- N2AS SIP Application Server (internal media server feature)
This section describes how the announcement audio stream is constructed by combining:
- The Announcement ID(s),
- The Language Name,
- The variable part types and values.
LhoSipApp also supports “external” announcement-playing by hand-off to an external
SRP or similar supported media server, which then becomes responsible for assembling the audio fragments
using those input parameters.
Naturally, if that external SRP is the N2SRP as implemented by
SrpSipApp then the announcement construction
rules described here will again be applicable.
Mapping File & Rules
The announcement mapping configuration may be stored locally on-disk in a JSON format file named
Alternatively the announcement mapping configuration and associated files may be stored in a PostgreSQL database
accessible to the service node (ideally co-located with the service node n2svcd instance for low latency robust
The N2SRP management GUI is responsible for synchronizing the necessary files across the various N2SRP nodes from
the main management node. When using file-based storage, this is done using the
rsync application. When using
database storage, syncing is done using the built-in database replication system.
This JSON file is constructed using the following JSON structure. The file definition also describes the rules for assembling announcements. The mechanism for constructing variable parts is defined separately for each language.