ZyXEL Communications IES-5005 - Manual (Page 54)

IES-5000/5005/6000 Support Notes
53
802.1ag CFM
What is CFM?
IEEE 802.1ag Connectivity Fault Management (CFM) allows service providers to manage
each customer service instance individually. A customer service instance, or Ethernet Virtual
Connection (EVC),is the service that is sold to a customer and is designated by the
Service-VLAN tag. Hence,802.1ag operates on a per-Service-VLAN (or per-EVC) basis. It
enables the service provider to know if an EVC has failed, if so, provides the tool to enable
rapid isolation of the failure.
This function would be absolutely critical in the following scenarios:
1. A SNMP trap indicates a fault has occurred in the network. How does the service
provider know exactly which customers are affected, particularly if there are complex
failover mechanisms in place?
2. An instance has failed. How does the service provider discover this?
3. A link or devices in an instance fails. How do the other devices find out so they can
reroute around the failure.
4. An instance was just installed. How does the service provider confirm that it is
operational?
802.1ag providers the tools to do all of the above easily and quickly, thus reducing operating
costs, increasing availability.
Operator A
Provider
Customer
Customer
Provider
Operator Operator Operator
Operator B Operator C
Customer CFM
Provider CFM
Operator CFM
• Customer detects failure: diagnose and isolate the failure, report to providers
• Provide detects failure: diagnose and isolate the failure, report to operators
• Operator detects failure: diagnose and find out root causes
• MS: Management System
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