Clearspan® Product Overview R19
Aastra – 2740-007
2014 Clearspan® is a Registered Trademark of Aastra Technologies Ltd.
Page 22 of 93
Figure 11. Typical High-level BladeCenter Architecture.
Each discreet server has dual power supplies, quad NIC interfaces and RAID disk drives.
2.2.2
Software Application Redundancy
System reliability is the result of more than just hardware compliance. Clearspan provides a total
system solution for redundancy that addresses potential points of failure in
both
the Clearspan
servers
and
the enterprise
’s IP network. This architecture, as described in the following section, is
designed to ensure that service is maintained in the event of a network and/or server failure.
2.2.2.1
Application Servers Redundancy
Application Servers are deployed in primary/secondary cluster mode. Under normal operation, the
primary Application Server handles all traffic. When there is a server or network failure, users are
automatically rolled over to the secondary Application Server on the next call (either originating or
terminating) that involves a subscriber. This ensures continuous access to normal calling for users.
The primary and secondary Application Servers are synchronized using the following mechanisms:
Cluster Data Replication: The Application Server TimesTen database is replicated
between the primary and secondary servers using TimesTen replication capabilities.
Subscriber data-sharing ensures proper behavior upon rollover of an access device to the
secondary Application Server.
Cluster File Synchronization: Announcements, voice mail greetings, web branding, and
other file-based configuration are synchronized using RSYNC, which is an open-source
utility commonly used to mirror Internet web sites.
2.2.2.2
Media Server Pools Redundancy
Media Server redundancy is accomplished through N+1 pooling. All Media Servers are
independent. A failure of a Media Server results in the Application Server timing out on attempts to
reach that server, and then routes to the next available Media Server.
