An Application Demonstration of the Reliable Server Pooling Framework

The convergence of classical PSTN and IP networks requires the transport of SS7 signaling over IP. Since SS7 has very strict availability requirements for the signaling components, redundancy is mandatory. The goal of the IETF RSerPool working group is to define a lightweight, flexible and real-time redundancy concept to fulfill the availability requirements of SS7: Reliable Server Pooling (RSerPool). RSerPool is currently under standardization, its functionality and improvement are subject of our research. As part of our RSerPool research, we have created an implementation prototype together with an example application. In our proposed demo, we will explain the fundamental protocol mechanisms of RSerPool and demonstrate its behavior and the impacts of component failures to an example application. 1 What is Reliable Server Pooling? The convergence of classical circuit-switched networks (i.e. PSTN/ISDN) and data networks (i.e. IP-based) is rapidly progressing. This implies that PSTN signaling via the SS7 protocol is transported over IP networks. Since SS7 signaling networks offer a very high degree of availability (e.g. at most 10 minutes downtime per year for any signaling relationship between two signaling endpoints; for more information see [9]), all links and components of the network devices must be redundant. When transporting signaling over IP networks, such redundancy concepts also have to be applied to achieve the required availability. Link redundancy in IP networks is supported using the Stream Control Transmission Protocol (SCTP [12, 10]); redundancy of network device components is supported by the SGP/ASP (signaling gateway process/application server process) concept. However, this concept has some limitations: no support of dynamic addition and removal of Pool User Po ol E le m en t P E2 Pool Element PE1 ASAP Protocol ENRP Protocol Application Protocol