H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 10)

2
MTTR = fault detection time + hardware replacement time + system initialization time + link recovery time
+ routing time + forwarding recovery time. A smaller value of each item, a smaller MTTR and a higher
availability.
High availability technologies
Increasing MTBF or decreasing MTTR can enhance the availability of a network. The high availability
technologies described in this section meet the level 3 high availability requirements in the aspect of
decreasing MTTR.
High availability technologies can be classified as fault detection technologies or protection switchover
technologies.
Fault detection technologies
Fault detection technologies enable detection and diagnosis of network faults. NQA is used for
diagnosis and evaluation of network quality. Track works along with other high availability technologies
to detect faults.
Table 2 Fault detection technologies
Technology Introduction Reference
NQA
Network Quality Analyzer (NQA) analyzes network performance,
services and service quality through sending test packets, and
provides you with network performance and service quality
parameters such as jitter, TCP connection delay, FTP connection delay
and file transfer rate.
Network
Management and
Monitoring
Configuration
Guide
Track
The track module is used to implement collaboration between different
modules. The collaboration here involves three parts: the application
modules, the track module, and the detection modules. These modules
collaborate with one another through collaboration entries. That is,
the detection modules trigger the application modules to perform
certain operations through the track module. More specifically, the
detection modules probe the link status, network performance and so
on, and inform the application modules of the detection result through
the track module. Upon aware of the changes of network status, the
application modules deal with the changes to avoid communication
interruption and network performance degradation.
Chapter "Track
configuration"
Protection switchover technologies
Protection switchover technologies aim at recovering network faults. They back up hardware, link, routing,
and service information for switchover in case of network faults to ensure continuity of network services.