Wavetek ANT-20, Operating Manual

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ANT-20/ANT-20E Broadband Analyzer/Generator
Introduction I-5
3 Test applications
3.1 ATM performance analysis
The basic version of the tester supports analysis of the ATM layer “Quality of Service”.
Measurements are performed in conformance with ITU-T Recommendation O.191,
“SPECIFICATIONS OF MEASURING EQUIPMENT; Equipment to Assess ATM Layer Cell
Transfer Performance”.
This standard describes the currently most reliable ATM measurement method. It basically
defines test cell formats and evaluation algorithms such as a 4-byte sequence number, the
timestamp and a CRC16 check per cell.
By these definitions, test results in accordance to O.191 were registered, which can be
compared directly.
The following quality parameters are reliably and unambiguously determined from the test cell
data using the measurement algorithm:
•
Error-related network performance parameters
– CER, Cell Error Ratio
– CLR, Cell Loss Ratio
– SECBR, Severely Errored Cell Block Ratio
– CMR, Cell Misinsertion Rate
•
Availability-related network performance parameters
– LPAC, Loss of Performance Assessment Capability
•
Delay-related network performance parameters
– CTD, Cell Transfer Delay
– CDV, Cell Delay Variation
Using this measurement method, particularly precise long term measurements are possible
which allow evidence of the constant high quality of a connection to be obtained.
3.2 Traffic management tests
Various test functions assist you in testing the ATM traffic management functions or to optimize
their settings.
In particular, the tester supports the following:
•
Definition and agreement of the ATM traffic contract for ATM circuits
•
Checking the contract guarantees: Cell rates, cell losses, cell delay
•
Tests using the “leaky bucket” algorithm (GCRA, generic cell rate algorithm)
•
Simulations with traffic shaping
•
Compliance and conformance simulations with ATM circuits and ATM sources
•
Tests in connection with connection admission control
•
Tests of UPC (usage parameter control) functions
•
Analysis of cell loss priority control
•
Tagging tests
•
Explicit forward congestion analysis
In preparation:
•
AAL-5 frame discard testing