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Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001
Chapter6 Card and Service Configuration Service Resource Module
Bit Error Rate Testing Through an MGX-SRM-3T3
The MGX 8230 shelf can perform a bit error rate test (BERT) on an active line or port. This type of
testing disrupts service because a BERT session requires the tested path to be in loopback mode. In
addition, the pattern test repla ces user-data in the path with the test pattern. The applicable lin e t ypes
and variations for a DS1 are:
•A T1 or E1 line
•Fractional portions of a T1 line that add up to a DS1
•A single 56 Kbps or 64 Kbps DS0
•A DS0 bundle consistin g of N x 64 Kbps DS 0s
With a set of MGX-SRM-3T3/ C cards in the system, you ca n in it iate a BERT session on an
MGX-FRSM-2CT3 or any eight-port service module. (In contrast, the MGX-FRSM-2T3E3,
MGX-CESM-T3, and MGX-CESM -E3 do not use the MGX-SRM-3T3/C for BERT. See the sections for
these service modules in t hi s ch ap te r for applicable BERT.)
The MGX 8230 bus structure supports one BERT session per upper or lower bay, so the shelf can run a
maximum of two sessions at once. When you specify the target slot through the CiscoView application
or the CLI, the system deter m i ne s if a B E RT configu ration already exists in that bay. Af ter t he s y stem
determines that no BERT con figuration exists in the app licable bay, the display present s a menu for the
BERT parameters.
The CLI commands (whose functions correspond to CiscoView selections) are:
•cnfbert to configure and start a tes t
•modbert to inject errors into the B E RT bit s t re am
•dspbert to display the parameters and results of the current test
•delbert to end the current test
Note When a BERT session begins, all connectio ns on a li ne or p o rt g o in to al ar m a nd return to normal
when the test ends. Co n s e q ue nt ly, the test may result in o th e r t yp e s of traffic (such as AIS).
During configuration, the p ar amete r d isp lay or men u i tems depe nd f i rst on the c ard t ype and w he ther the
test medium is a physical line or a logical port. Subsequent choices are t est type, test patterns, loopback
type, and so on. See the Cisco MGX 8230 Wide Area Edge Switch Command Reference for details on
cnfbert and the other BERT commands . Th e con cat enat ion o f m enu t o me nu i s ext e nsive, so this section
contains tables of menu selections based on the card types and the test type.
The test type can be pa ttern, loopback, or DDS seek. The choice of test type leads to fu rthe r m en u
displays. Following the tables of menu choices, the remaining sections define the parameters in these
menu choices.
•For AX-FRSM-8T1, AX-CESM-8T1, and MGX-FRSM-2CT3, see Table 6- 5 pattern tests and
Table 6 -6 for loopback tests.
•For AX-FRSM-8E1 and AX-CESM-8E1, see Table 6- 7 for pattern tests and Table 6- 8 for loopback
tests.
•For MGX-AUSM-8T1 , se e Ta ble 6-9 for pattern tests and Ta ble 6-1 0 for loopback tests.
•For MGX-AUSM-8E1 , se e Ta ble 6-1 1 for pattern and Table 6- 12 loopback tests.