Teledyne LeCroy USBTracer_Trainer - Users Manual - Manual (Page 132)

Chapter 5: Reading a Trace USB Protocol Suite User Manual
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LeCroy Corporation
5.41 Switch to PTP Sessions
A session is a state of persisting communication between a device and a host during
which the connection is continuous and the login and other communication parameters
do not change. A session begins with an OpenSession operation, which establishes the
communications connection and parameters, and ends with a CloseSession operation.
A session contains all object transfers (and their transactions), plus all transactions that
do not belong to object transfers, between an OpenSession operation and a
CloseSession operation. For PTP, all PTP Object Transfers and all PTP Transactions
that occur from the OpenSession operation to the CloseSession operation is a single
PTP Session.
The PTP Session trace viewing level is the highest PTP level.
To view PTP sessions, switch to the PTP Session trace viewing level:
• Click on the toolbar.
OR
• Select View > PTP Session Level.
OR
• Select Setup > Display Options to display the Display Options window, check PTP
Session, and then click OK.
5.42 Switch to SCSI Operations
To view SCSI operations, switch to SCSI Operations viewing level:
• Click on the toolbar.
OR
• Select View > SCSI Operation Level.
OR
• Select Setup > Display Options to display the Display Options window, check
SCSI Operation, and then click OK.
5.42.1 SCSI Metrics
The SCSI Metrics are:
•
Address
• Number Of Transfers: Total number of transfers that compose the SCSI operation
• Response Time: Time to transmit on the USB link, from the beginning of the first
transfer in the SCSI operation to the end of the last transfer in the SCSI operation
• Latency: Time from the transmission of the SCSI command to the first data trans-
mitted for the SCSI IO operation
• Data To Status Time: Time between the end of data transmission for the SCSI
operation and the status transfer
• Payload: Number of payload bytes transferred by the SCSI operation