Chapter 3
Configuration Procedures for the Cisco 627
Interpret Statistics
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Cisco 600 Series Installation and Operation Guide
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Signal-to-Noise (SNR) Margin—Amount of increased received signal noise
(in decibels) relative to the signal noise power level the unit is designed to
tolerate without disconnecting from the network. The SNR Margin range is
-64.0 to +63 dB in 1 dB increments. SNR Margin is calculated every
10 seconds. The previous value is moved to the Previous SNR Margin field.
•
Previous SNR Margin—Last SNR Margin measurement, which occurs
approximately every 10 seconds.
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Operation, Administration, Maintenance (OAM) Loopback Cells—The Cisco
627 supports the Operation, Administration, and Maintenance (OAM) F5
loopback cell to verify end-to-end ATM network connectivity. The OAM-F5
loopback cell is generated by a network-side system. The cell is injected into
a specific virtual circuit along with the normal user traffic flow. The cell is
carried unmodified by each intermediate ATM switching node until it arrives
at the circuit's other endpoint such as the Cisco 627. The receiving endpoint
modifies the cell payload to indicate that the cell has been looped back and
transmits this new cell back into the ATM circuit. It is relayed by each
intermediate node until it arrives at the original transmitting endpoint. The
receipt of this cell indicates a valid end-to-end connection between the two
endpoints over the intervening ATM network.
