[EFM] Loop back and BERT test functionality for service providers
Matt,
The loop back BERT tests are very similar in function to the conformance
tests that are done with Ethernet devices per the requirements of the
standard. The big difference is that they are done in the field, ad hoc by
field test personnel and automated systems. I has occurred to me that the
conformance test pattern for GbE could be used for this.
Coming out of the Raleigh meeting, there was supposed to be a group of
people that were getting together at San Diego to discuss the functionality
that was required by service providers for which they used a loop back
test, and BERT testing. That did not happen. So that this discussion does
not get bogged down again at the next meeting, here is the material that
Bob Barrett and I put together on the topics. I believe that I have
already sent it to you once, but I could be mistaken.
Loop Back and BERT Test Functions
A Loop Back Test is a conformance test to verify the ability of a
communications infrastructure and facility to meet certain performance and
operational management capability requirements in order for a service
provider to meet the contractual requirements of service level
agreements. During the loop back test, the customer revenue data stream is
disabled and replaced with a loop back test pattern. Often the default
loop back test pattern is a worst case error free BERT pattern. Loop back
tests are run as part of a remote operations support function to prevent
the need for sending people to perform the test and measurement functions
at the customer site. Minimal levels of loop back testing is also
available to service provider customer to allow them to do their
own service conformance verification.
The loop back test performs the following functions:
1. Verifies the full bandwidth capability of the service
infrastructure and facility in both directions,
2. Verifies that the operational management command and control
functions operate properly under worst case load conditions of the revenue
data stream in both directions,
3. Verifies that the performance monitoring functions operate properly
in both
directions,
4. Verifies the data reliability performance of the infrastructure and
service facility,
5. Verifies that any fault reporting functions operate properly in
both directions,
6. Verifies that any other facility configuration and service
management functions operate properly under worst case load conditions of
the revenue data stream in both directions,
7. Verifies that any service management and support functions operate
properly in both directions regardless of revenue data stream load,
8. Verifies the performance of the infrastructure and/or service
facility as part of a customer problem resolution process,
9. Verifies that an infrastructure and/or service facility are fully
operational after having been properly repaired.
The Bit Error Rate Test (BERT) test, as used by service provider field
operations, performs the following functions as part of a conformance loop
back test:
1. The data reliability performance measurements of the infrastructure
and service facility under worst case revenue data stream load by measuring
the bit error rate under worst case pattern and load conditions,
2. Tests the performance monitoring capability of the infrastructure
and service
facility by introducing errors into the revenue data stream using a test
pattern with and without deliberate bit errors in the test pattern, without
changing the error check function indicator,
3. Verifies that some of the operational management command and
control functions operate properly by forcing the near end and far end
interfaces into and out of different BERT test functions while introducing
errors into the revenue data stream test pattern.
Thank you,
Roy Bynum