H3C Technologies H3C S10500 Series Switches - Manual (Page 11)

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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 2 and level 3 high availability requirements by
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. CFD, DLDP, and Ethernet
OAM are data link layer fault detection technologies. 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
CFD
Connectivity Fault Detection (CFD), which conforms to IEEE
802.1ag Connectivity Fault Management (CFM), is an end-to-end
per-VLAN link layer Operations, Administration and Maintenance
(OAM) mechanism used for link connectivity detection, fault
verification, and fault location.
CFD configuration in
the High Availability
Configuration Guide
DLDP
The Device link detection protocol (DLDP) deals with unidirectional
links that may occur in a network. Upon detecting a unidirectional
link, DLDP, as configured, can shut down the related port
automatically or prompt users to take actions to avoid network
problems.
DLDP configuration in
the High Availability
Configuration Guide
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.
Ethernet OAM
configuration in the
High Availability
Configuration Guide
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.
BFD configuration in
the High Availability
Configuration Guide
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.
NQA configuration
in the Network
Management and
Monitoring
Configuration Guide
Monitor Link
Monitor link is a port collaboration function. It is usually used in
conjunction with Layer 2 topology protocols. The idea is to monitor
the states of uplink ports and adapt the up/down state of downlink
ports to the up/down state of uplink ports, triggering link switchover
on the downstream device in time.
Monitor link
configuration in the
High Availability
Configuration Guide