Communications service providers are increasingly delivering Ethernet business services for retail, wholesale, and mobile backhaul applications. These services require high availability and guaranteed performance, as specified in service level agreements (SLAs) that are a critical part of the service contracts.
Ethernet operations, administration, and maintenance (OAM) tools have emerged as a simple way for service providers to monitor and manage the Ethernet circuits and ensure that they conform to SLAs. The Calix Management System (CMS) supports a variety of Ethernet OAM functions, including remote activation of OAM test head features as well as several OAM data collection and reporting tools.
CMS currently has MEF service templates to perform Remote ONT Activation of MEF-Ethernet Virtual Connections (EVCs) across the Calix Unified Access Infrastructure. CMS 11.2 will offer integrated tools for remote management of Ethernet OAM standards referenced in MEF-17, including:
- RFC-2544 pre-qualification and out of service testing procedures
- IEEE 802.1ag connectivity fault management (CFM)
- ITU-T Y.1731 performance management
Service Initiation (RFC-2544 Tests):
CMS enables remote Ethernet services test provisioning to characterize new service EVCs to ensure that SLAs can be met. CMS follows the steps below to achieve this:
- CMS provisions MEF-EVCs (E-LINE, E-LAN) over which the service will be delivered.
- CMS enables RFC-2544 testing of the service by remotely initiating RFC-2544 "reflector" with MAC swap at the ONT.
- The ONT acting as a RFC-2544 reflector loop backs frames being sent from a centralized test head.
- The centralized test head collects the reflected frames to compile SLA measurements of the service and characterize how the EVC performs under different frame sizes, bursting, loading of the UNI, etc.
- CMS then disables the ONT "reflector" to allow normal use as the UNI in the service EVC.
- CMS then utilizes "in service" fault and performance utilities including above mentioned Y.1731 and 802.1ag features.
Fault Management (CMS Service Monitoring):
CMS remotely activates, retrieves, and displays fault management (CFM) compliant to 802.1ag. The CMS Ethernet Service Assurance Portal minimizes mean time to report by isolating failures when RDI events are received, injecting loopback and link trace messages between service UNI's. CFM features include:
- Ethernet Loopback of an EVC end to end, specific to a dedicated VLAN path between two ONTs and UNIs at the customer service demark. This is referred to as an Ethernet based ping.
- Ethernet Link-trace to mark every MIP in the EVC path on that VLAN, similar to a Layer3 IP Trace-route command.
- Continuity Checks (CC) with Remote Defect Indicator (RDI), used as an Ethernet based VLAN aware heartbeat, to notify when an EVC path is no longer forwarding data specific to that VLAN-ID.
- Alarming and Events based on RDI and SNMP are integrated into the CMS alarms screen to notify network administrators when an EVC circuit has lost connectivity or failed.
Performance Monitoring:
CMS remotely activates and retrieves Y.1731 PM measurements and data from EVC circuit endpoints, and also displays PM data in the GUI and in CMS reports. Y.1731 PM data includes:
- Frame loss (FL) data counters and as % of CIR on EVCs in time intervals
- Frame Delay (FD) of the time it takes for frames to traverse the circuit and arrive at the remote end of the EVC
- Frame Delay Variation (FDV) measuring the difference in arrival times of frames traversing the EVC – commonly referred to as "jitter"
- Delay variation to assure SLA compliance as while monitoring business services for outages.
SLAs and CMS Service Compliance Reporting
Key to delivery of business services is the service provider's ability to demonstrate SLA compliance to its business customers. CMS provides data collection capabilities that will allow the provider to export and generate compliance reports based on loss, delay, and delay variation parameters defined in their SLAs.
Service level agreements are defined in terms of near end (NE) and Far end (FE) loss ratio, frame delay, and delay variation. CMS generates SLA violation reports based on information gathered by the Calix ONT endpoints. CMS continually monitors the business services for compliance and SLA violations, and generates reports for business customers.
