Clearspan® Product Overview R19
Aastra – 2740-007
2014 Clearspan® is a Registered Trademark of Aastra Technologies Ltd.
Page 21 of 93
2.2
Core Redundancy and Fault Tolerance
True system reliability is achieved through a combination of software engineering, server
redundancy, and networking capabilities. Recognizing this, Aastra has gone to great lengths to
address issues at every layer in the system architecture to achieve the highest levels of reliability,
redundancy, and performance.
The Clearspan Core contains no single points of failure. A fully redundant Clearspan system
incorporating all components delivers over 99.999% availability. There are several layers of
redundancy within the Clearspan Core, and they include:
Hardware Redundancy
Software Application Redundancy
Network Redundancy
Software Reliability
Geographic Redundancy
Each of these elements play an important role in the overall architecture and are explained further
in the following sections.
2.2.1
Hardware Redundancy
Within the IBM BladeCenter, hardware components are replicated and have the following features:
Dual processors, redundant memory channels, redundant hard disk drives, and quad
Network Interface Cards (NICs) for each blade server
Redundant power supplies
Redundant Gigabit Ethernet switches
Redundant layer 1 / layer 2 interface modules
Redundant fan assemblies
The high-level block diagram of the BladeCenter is shown in the following figure. Utilizing the
multiple NICs, each blade has several paths for redundancy and fault tolerance.
