H3C Technologies H3C SR8800 - Manual (Page 11)

2
High availability technologies
As previously mentioned, increasing MTBF or decreasing MTTR can enhance the availability of a
network.
High availability technologies can be classified into fault detection technologies and protection
switchover technologies.
Fault detection technologies
Fault detection technologies enable detection and diagnosis of network faults. Ethernet OAM is a data
link layer fault detection technology. BFD is a generic fault detection technology that can be used at any
layer. NQA is used for diagnosis and evaluation of network quality. Monitor Link and track work along
with other high availability technologies to detect faults through a collaboration mechanism.
Table 2 Fault detection technologies
Technology Introduction Reference
Ethernet OAM
As a tool monitoring Layer 2 link status, Ethernet OAM is mainly used
to address common link-related issues on the “last mile.” You can
monitor the status of the point-to-point link between two directly
connected devices by enabling Ethernet OAM on them.
Chapter
“Configuring
Ethernet OAM”
BFD
Bidirectional forwarding detection (BFD) provides a single mechanism
to quickly detect and monitor the connectivity of links or IP forwarding
in networks. To improve network performance, devices must quickly
detect communication failures to restore communication through
backup paths as soon as possible.
Chapter
“Configuring BFD”
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
Monitor Link
Monitor Link works together with Layer 2 topology protocols to adapt
the up/down state of a downlink port to the state of an uplink port. This
feature enables fast link switchover on a downstream device in
response to the uplink state change on its upstream device.
Chapter
“Configuring
Monitor Link”
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 accordingly to avoid
communication interruption and network performance degradation.
Chapter
“Configuring
track”