3Com CoreBuilder 9000, Руководство пользователя

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Traffic Statistics 373
The call is transferred by the following steps:
1 The edge device translates the Ethernet frames into ATM cells and
forwards them to the ATM output port.
2 The ATM output port writes the VPI/VCI values for the external link for
the VC on the cell header and transmits the cells on the line that connects
the port to the switch. Cells for simultaneous calls are multiplexed on the
line.
3 The cells that are received by the switch are identified by VPI/VCI and sent
through the virtual channel internal link to the appropriate output port.
4 The output port overwrites the VPI/VCI values in the cell header with ones
for the next external link and transmits the cell over the line to the edge
device.
5 The edge device identifies the VPI/VCI values, translates the cells back into
frames, and sends them out the appropriate Ethernet port.
Traffic Statistics
The CoreBuilder
®
9000 ATM Enterprise Switch provides the following
types of flow statistics:
Physical Statistics
ATM Statistics
AAL5 Statistics
AAL5 Control Statistics
Signaling Statistics
Physical Statistics Physical statistics include counts of SONET BIP errors, SONET FEBE errors,
and SONET state statistics. For details and examples, see “Physical Layer
Statistics” on page 205.
ATM Statistics ATM port statistics include counts of total cells, unrecognized cells, and
cells with hec errors. ATM-Layer VPI/VCI Statistics include a cell count for
a VPI/VCI of those cells with CLP set and those with CLP clear. For details
and examples, see “ATM-Layer Statistics” on page 209.
AAL5 Control
Statistics
A cumulative total of AAL5 PDUs presented according to maximum PDU
size, number of PDUs bytes, errored PDUs, and PDUs discarded due to full
queues.
Signaling Statistics A cumulative total of transmitted and received signaling messages
according to type of message.