We design to test the system performance, NGGK (Next Generation Gatekeeper) supporting TRIP (Telephony Routing over IP) is realized based on VOVIDA TRIP protocol stack 1.0.0, which is an open source stack.All four TRIP messages above are implemented along with following NGGK functionality:
- Peer-to-peer connection and management using OPEN message in Finite State Machine (FSM).
- Routing information organization in TRIB databases.
- Intra-Connecting Domain NGGK routing synchronization with flooding process new added.
- Inter-Connecting Domain NGGK routing advertisement based on routing aggregation and selection.
- And we add new function to support of E.164 Numbers to resolve zone prefix.
In realization, we find that NGGK pairs may initiate a transport connection to the peer and close it at the same time. In case, two NGGKs will bother with connection conflicts without success for long time. It should automatically close the connection of a NGGK with low IP address after comparison.
In the testing system showed in Fig. 1, there are six modules for implementation of TRIP in system: TRIP Level Management, TRIB, FSM, Policy Center, Message Center and System Service. TRIP Level Management couples TCP transport layer to receive network events, accepts the initial system parameters such as timer, policies from real time applications. TRIB comprises four types databases to store corresponding routingin formation. FSM is the core module, which provides a basic framework of TRIP operation, it has six states: Idle,Connect, Active, OpenSent, OpenConfirm, Established. Policy Center is responsible for policy driven messages operation interior a NGGK, drives FSM and makes TRIB update in a designated way. Message Center accepts message from TRIP Level Management, parses them to detect if any error occurs, and makes responses. System Service module invokes APIs of VOVIDA TRIP stack and provides basic API service for all other modules.
Fig. 1. Module architecture in the testing system using TRIP for NGGK routing language