Metrodata ATM CBR DSU, User Manual

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ANALYSING PERFORMANCE
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6 . 7. 2 AAL1 displays
In Metrodata products AAL1 statistics are accessed via the PERFORMANCE DATA screen
when the CBR interface has been selected. The menu item ATM LAYER STATS gives
access to the AAL1 statistics. The path is:
MAIN SET-UP /PERFORMANCE DATA /[select CBR interface] /ATM LAYER STATS
Figure 6.23 AAL1 stats selection
The display section entitled Seg Cells refers to CBR traffic which has been segmented by
the AAL1 process, and the display section Reass Cells shows data for ATM cells which have
been re-assembled into CBR traffic streams. The parameter definitions are given below.
Figure 6.24 AAL1 Display parameters
PERFORMANCE DATA
Interface E1
Display mode Updated summary
Summary style G.821
Phys layer stats <display>
Error type LCV Errors
ATM layer stats <display>
Clear all data
HIGHLIGHTED letter - select item
<escape> - exit menu
Display Description
Valid Amount of time in seconds in which the statistics are valid
LOSEQ Secs Loss of AAL1 sequence alignment in seconds duration
Seg Cells
Number of AAL1 cells segmented
B/W usage Bandwidth usage as a percentage of full loading
Reass Cells Number of AAL1 cells received for reassembly
Good Cells Number of good AAL1 cells passed to reassembly buffer
Corr Cells Number of AAL1 cells corrected using sequence byte CRC and
passed to reassembly buffer
Padded Cells Number of AAL1 cells padded (Padding is 47 bytes of all 1’s)
Error rate
Corrected AAL1 cell or padded AAL1 cell error rate