High Availability Technologies; Fault Detection Technologies - HP A5830 series Configuration Manual

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 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
CFD
DLDP
Ethernet OAM
BFD
NQA
Monitor Link
Introduction
CFD, which conforms to IEEE 802.1ag CFM, is an end-to-end per-
VLAN link layer OAM mechanism used for link connectivity
detection, fault verification, and fault location.
The 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.
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.
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.
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.
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.
8
Reference
CFD configuration in
High Availability
Configuration Guide
DLDP configuration in
High Availability
Configuration Guide
Ethernet OAM
configuration in High
Availability
Configuration Guide
BFD configuration in
High Availability
Configuration Guide
NQA configuration
in Network
Management and
Monitoring
Configuration Guide
Monitor link
configuration in High
Availability
Configuration Guide