Compaq ServerNet ServerNet II Installation Manual page 171

ServerNet II Diagnostics Resources H-5
Local Host Computer
Your Application
Upper
Online
Level
Diagnostics
Protocol
Software
SANMAN
Remote
ServerNet
SPAD
Node
Network
Adapter
Card
Acknowledged Write ServerNet interrupt
packet contains request
Acknowledged Write ServerNet interrupt
packet contains response
Figure H-5. Echo Test
A more detailed view of the echo test is shown in Figure H-5. The Diagnostics on the local host
calls the IOCTL_SANMAN_ECHO function. The System Area Network Manager (SANMan)
formats a ServerNet II interrupt packet and sends it to the SPAD driver, resulting in an
Acknowledged Write (Interrupt) ServerNet II Packet being sent to the appropriate address in the
remote node. This packet contains the Echo request and data. The target node accepts and
processes the request. If all is well, the target node returns the same data with an Acknowledged
Write (Interrupt) ServerNet II Packet.
Echo Test with Target Nodes
Only ServerNet II SAN nodes can be the targets of echo tests. Computer nodes can be the
targets also.
NOTE: Switch nodes cannot be targeted with the echo test; use the routing test to target Switch nodes.
When an echo test target is a computer, the target node's SANMan is responsible for processing
and responding to the request. The SPAD driver is involved between SANMan and the SAN as
shown in Figure H-6.