Intel SIU520 SS7 manual Abstract, Introduction

Building Fault-tolerant SS7 Systems Using the Intel® NetStructure™ SIU520 SS7 Signaling Gateway Application Note

Abstract

In order to achieve five-nines (99.999%) reliability and a high degree of fault tolerance in an SS7 environment using Intel® NetStructure™ SIU520 signaling gateways, an SS7 end point spread over two signaling interface units (SIUs) and multiple application servers can be configured and deployed. Splitting the protocol processing functionality of a signaling point by implementing an SS7 node over two SIUs isolates the hardware processors on the chassis from each other. This separation lets one processor continue if the other fails, allowing the system to remain in service. Distributing application processing of a signaling point on multiple application servers not only increases the total capacity of a system, but also offers a higher level of fault tolerance in the user application space.

Intel NetStructure SS7 products are designed for this dual-processor approach and provide the architecture for splitting a point code over two active SS7 protocol engines. Using this technique, the links in an SS7 link set can be spread between two separate chassis when Intel NetStructure SS7 boards are installed in each.

This document describes the features of the SIU520 SS7 signaling gateway that are available to build SS7 solutions and reach the five-nines requirements of telco-grade service platforms.

Introduction

This application note describes the architecture of the Intel NetStructure SIU520 signaling gateway, reviews the most common potential points of failure of an SS7 system based on this product, and explains methods that can mitigate each of these potential failure points. This document also explains in detail the configuration and run-time operation considerations of a dual-resilient SIU520-based system.

Because of the high expectation of service reliability by the users of public telephone networks, equipment manufacturers and system integrators demand high levels of fault tolerance and availability, often citing the five-nines for availability (requiring a system to be operational for 99.999% of the time).

These systems need to continue to offer service even when partial hardware or software failure has occurred. There are several well-known methods of achieving this type of reaction to partial failure in the signaling component of communications networks, including:

■Multiple signaling paths (SS7 links and link sets) to each end point

■Distribution of these paths through independent inter- faces and cabling

■Distribution of the processing of SS7 terminations at a single signaling point between multiple processing cards in a single SIU

■Physical isolation and duplication of the SS7 interface for a single signaling point on independent protocol engines sharing a single point code

■Splitting the functionality of the application layer between multiple application servers

The first method can be achieved by implementing multi- ple links (64 Kb/s or 56 Kb/s channels) between two adjacent inter-communicating points. (By definition, these links will all be in the same link set.) The last two can be accomplished by using two independent, but co-operat- ing, SIU520s relaying the SS7 signaling to a distributed application layer split over multiple application hosts.

Note: Readers should be familiar with Signaling System 7 (SS7) concepts. They should also be aware that the information contained in this application note is provided as a complement to the Intel NetStructure SIU520 Developer’s Manual; hence, an understanding of the terms defined in the developer’s manual is assumed.

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