Ethernet OAM

Operations, Administration & Maintenance (OAM) refers to protocols and mechanisms that help operator to achieve the so-called FCAPS functionalities.

FCAPS is the key concept used to define the overall functionality of an enterprise management system and the acronym stands for Fault, Configuration, Accounting, Performance, and Security.

In particular Ethernet operations, administration and maintenance (EOAM) refers to protocols on Ethernet networks that provide features like fault indication, performance monitoring, security management, diagnostic functions, configuration and service provisioning.

Different standards have been developed based on the concept of EOAM, such as:

For sake of clarity it is important to say that the IEEE 802.1ag and the ITU-T Y.1731 are identical in the connectivity management part.

What ITU provides in addition to that is performance management through the mean of performance messages.

In one of the activities carried on in GEANT3, Ethernet OAM functions were tested over a dedicated testbed established by five NRENs (JANET, NORDUnet, PSNC, SURFnet and CESNET) and one University (Essex Univerity).

The main idea behind it was gaining some initial experience in monitoring and troubleshooting wide-area point-to-point Ethernet connections using the Ethernet OAM functions.

The equipment used in the testbed was from different vendors, including Ciena, Extreme Networks, Cisco, and Brocade. Where the equipment didn't supported the required set of Ethernet OAM functions, small OAM agents on loan from vendors

(Overture and Accedian Networks) were installed in the trial sites. The links between sites were of different types: all of them had an Ethernet User Network Interface (UNI) at both ends, but in between different combinations of Multi-Protocol Label

Switching (MPLS), OTN, and tunnelling through IP were used.

The trial objectives were:

command lines to invoke state and performance data periodically, which is not ideal.
The main finding from the trial is that the Ethernet OAM functions embedded in the carrier-grade Ethernet equipment can be used for effective monitoring and visualizing of the health and performance of wide-area Ethernet services.

Some problems were experienced when measuring the One-way delay and the Jitter.
The document with all results and details can be found here.

Many vendors have implemented EOAM features in their devices in order to provide powerful troubleshooting tools like layer 2 traceroute.

References

--AlessandraScicchitano - last change 07 Jun 2012