Static random access memory (SRAM) database or flash memory database is used to provide backup for the program and data files of application software, so the exact program and data can be recovered from the backup database after CPU power failure or software reset.
n Power failure resuming protection and break-point resuming protection during software loading
The basic input/output system (BIOS) of the board is write-protected, that is, no modification is allowed. The program and data files of application software, which can be loaded on-line, are configured with check function to avoid data transmission error. After the software loading is interrupted, BIOS waits for resuming execution instead of starting the program or data files already loaded.
n Software upgrade protection
Two copies of NE software are stored in the system control & communication board so that a new software version can be loaded without affecting the current software running. The old version software will be replaced by the new version once the latter is confirmed as correct. This replacement does not affect the configuration information already set or NE equipment service. The old software version will continue to function if software upgrade fails.
3. Software Fault-Tolerance
n The software design of the OptiX OSN 9500 features: capability maturity model (CMM) for regulating management & development process, the idea of software engineering, extensive software quality assurance activities, the top-down program design and the object-oriented design. With these up-to-date software development, management and design technique, the quality and reliability of software are guaranteed.
n With the software integration idea, the layered modular design endows the software system high reliability and makes it convenient in maintenance and extension.
n The CPU has powerful load-balance and overload processing capability by adopting advanced method of driving and grooming traffic.
n Loopback alarm is provided, and the ongoing DCC communication is not influenced by the loopback.
4. Data Security
n The security is improved by adopting database module to perform unified management on the data.
n Both the database and database files have their own data check function.
n The database files are provided with hierarchical protection according to the importance of the data, so the error in the lower-level database will not affect the higher-level database.
n The database has one backup in SRAM and two backups (fdb0 and fdb1) in flash memory. The two sets of databases in flash memory provide protection to each other and backup protection to the database in SRAM.
3.3.2 Network Protection
The OptiX OSN 9500 features outstanding self-healing network protection and can provide multiple protection schemes at SDH layer against optical fiber cut, optical board damage or node failure. These protection schemes include MSP and SNCP, and so on. The protection switching time is less than 50 ms.
The ITU-T-Recommendation compliant or other international standards compliant self-healing protection schemes include:
n 1+1 or 1:N (N £ 14) linear MSP protection
n Self-healing ring protection (two-fiber bidirectional MS shared protection ring, two-fiber unidirectional MS dedicated protection ring, four-fiber bidirectional MS shared protection ring)
n Interconnection service protection in DNI and SNI mode
n SNCP
n Fiber-shared virtual path protection
n Mesh protection
What introduced below are the protection schemes provided by the OptiX OSN 9500.
1. Linear MSP Protection
The OptiX OSN 9500 supports both 1+1 and 1: N linear MSP with the switching time less than 50 ms, satisfying the requirement of the ITU-T Recommendation.
2. Self-Healing Ring Protection
The self-healing ring is also called ring network. The OptiX OSN 9500 can be used to form a MSP ring.
n Two-fiber unidirectional MSP rings
They are also called MS dedicated protection rings, composed of two pieces of optical fibers. One of the fibers (S) forms the working ring for service signal transmission, while the other (P) forms a dedicated protection ring in the opposite transmission direction.
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