Alcatel-Lucent 7750 SR - Ethernet Connectivity Fault Management (ETH-CFM)

Services
7750 SR OS Services Guide Page 99
Ethernet Connectivity Fault Management (ETH-CFM)
Ethernet Connectivity Fault Management (ETH-CFM) is defined in two similar standards: IEEE
802.1ag and ITU-T Y.1731. They both specify protocols, procedures, and managed objects to
support transport fault management, including discovery and verification of the path, detection
and isolation of a connectivity fault for each Ethernet service instance. CFM functionalities are
supported on SR and ESS platforms.
IEEE 802.1ag can detect:
• Loss of connectivity
• Unidirectional loss
• Loops
• Merging of services
CFM uses Ethernet frames and can be distinguished by its ether-type and special Ethernet
multicast addresses. CFM frames are only processed by IEEE MAC bridges. With CFM,
interoperability can be achieved between different vendor equipment in the service provider
network up to and including customer premises bridges. The following table lists CFM-related
acronyms used in this section.
Acronym Callout
CCM Continuity check message
CFM Connectivity fault management
LBM Loopback message
LBR Loopback reply
LTM Linktrace message
LTR Linktrace reply
ME Maintenance entity
MA Maintenance association
MA-ID Maintenance association identifier
MD Maintenance domain
MEP Maintenance association end point
MEP-ID Maintenance association end point identifier
MHF MIP half function
MIP Maintenance domain intermediate point