Backup and Fallback Operation

System Backup Features

Critical system components can be backed up to provide continuity in users voice services, data services, and other applications within a given radio network. The features requested from the following backup options can be included in the system solution.

1. Network Hardware Backup:

Ethernet switch, router, microwave radio link devices, network adapters in servers, and lines between these devices can be backed up. On this software, backup feature is provided by using required network communication and backup protocol.

 

 2. Radio Switching Unit Backup:

Radio Switching Software (Soft Switch) is a standard application running on Microsoft Windows and Linux. The Radio Switching Unit has two types of backup.


Local Backup Mode

In this mode, a second hardware is added to the first hardware of the Radio Switching Unit to provide physical and software redundancy. In normal operation, the soft switch software runs on the first hardware, while the software on the second hardware is pending. A separate backup service continuously controls the operation of the soft switch software. When the backup service encounters any problem in the soft switch software running on the first hardware, it activates soft switch software pending on the second hardware. In this case, all radios start working on the second hardware. In this way, both hardware backup and software backup are made.

 

Interprovincial Backup Mode

In this mode, the two soft switch softwares connected to each other via LAN / WAN connection can back up each other. Backup is performed automatically with user manual control. The inter-provincial backup mode is activated when on-board Radio Switching Unit is disabled in natural disasters such as earthquakes, fires, etc. If the redundant Radio Switching Unit is able to access the remaining repeater devices via the required IP connection, it will establish a connection with these repeater devices, allowing the remaining radio stations to continue their voice and data services. The inter-provincial backup status continues until the main Radio Switching Unit enters the circuit.

 

3. Application Server Hardware Backup:

With regards to data security, database and application servers need to work on separate physical and virtual machines. System reliability can be improved by adding a second server and DISK unit in order to prevent data loss and to ensure continuity of system services. Different virtualization techniques (such as VMware, Hyper-V) can be used during the backup.

4. Back-up of radio communication resources:

Repeater radio and channels can be backed up according to frequency and base station installation conditions except backup of network hardware and servers in the system. 

Fallback Operation Feature

Radio Communication System consists of subsystems, each covering a specific geographical area. A subsystem consists of multiple sites providing radio access in certain coverage areas. Wide area voice communication can be achieved with radio communication protocols over the radio system infrastructure with repeater devices in different sites. When there is a problem with the connection of a site to the centre or to other sites, the radios within the scope of relevant site can make in-cell audio conversations by receiving direct service over the repeater radio and control unit in the site (cell). Other voice and data services may be supported in fall back mode depending on the features of the radio terminals.