Calculating packet loss in Example 2
To calculate packet loss for a bridged PVC in Example 2, perform these tasks.
- Display the values for IN_FRAME_UNICAST on the ingress Ethernet port, and the values for OUT_FRAME, OUT_FRAME, and OUTPKTS on the egress ATM port:
- The ingress Ethernet ARU counter records the number of unicast packets -- IN_FRAME_UNICAST -- sent from the Ethernet port to the ATM port through the switch fabric. To display this number, in the CLI, enter this command:
| show port stats bridging <ethernet port> |
- The egress ATM ARU counter records the number of frames
-- OUT_FRAME -- that are received from the Ethernet port. To display this number, in the CLI, enter this command:
| show port stats bridging <atm port> |
- The egress ACC CPU counter records the number of unicast packets -- OutUcastPkts -- forwarded to the ATM port. To display this number, in the CLI, enter this command:
| show atm elan <elan number> |
- The egress SAR counter records the number of packets -- OUTPKTS -- sent out the ATM port. To display this number, in the CLI, enter this command:
| show port stats atmp <atm port> |
- The number of packets lost is approximately the difference between the IN_FRAME_UNICAST value and the OUT_FRAME value.
- The difference between the OUT_FRAME value and the OutUcastPkts value should be approximately the same as the value of the OutDiscards. To display the value for OutDiscards enter the following command:
show atm elan <elan number> output
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Note:
The values for OutUcastPkts and OUTPKTS are very similar which implies that there is no loss at SAR level.
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