NonStop S-Series Server Description Manual (G06.24+)

Principles of System Operation
HP NonStop S-Series Server Description Manual—520331-003
2-9
Packet Transmission and Reception
The BTE and AVT both have direct-memory access (DMA) engines and perform their
read and write operations without processor intervention, using buffer addresses that,
by prior agreement, have been allocated individually to particular ServerNet devices.
Figure 2-4. BTE Handles Local Requests; AVT Handles Incoming Requests
Locally Initiated Transaction Handling
Remotely Initiated Transaction Handling
Processor
BTE AVT
Processor
BTE AVT
Remote
ServerNet
Device
A
D
AD
Read Request
Read Response
Write Request
Write Response
Pulls
Data
Pushes
Data
Processor
BTE AVT
Processor
BTE AVT
A
D
D
Read Request
Read Response
Write Request
Write Response
READ
WRITE
READ
WRITE
A
Pulls
Data
Pushes
Data
Remote
ServerNet
Device
Remote
ServerNet
Device
Remote
ServerNet
Device
VST333.vsd