OpenVMS Cluster Systems - OpenVMS Systems - HP

Troubleshooting the NISCA Protocol
F.13 Programs That Capture Retransmission Errors
F.13.2 Partner Program
F.13.3 Scribe Program
Block 1: Enable_the_other_analyzers
Send message Distrib_Enable
and then
Go to block 2
Block 2: Wait_for_the_event
When frame matches LAVc_TR_ReXMT then go to block 3
Block 3: Send the distributed trigger
Mark frame
and then
Send message Distrib_Trigger
The partner program waits for the distributed enable; then it captures all of
the LAN traffic and terminates as a result of either a retransmission or the
distributed trigger. Upon termination, this program transmits the distributed
trigger to make sure that other LAN analyzers also capture the data at about
the same time as when the retransmitted packet was detected on this segment
or another segment. After the data capture completes, the data from multiple
LAN segments can be reviewed to locate the initial copy of the data that was
retransmitted. The partner program is shown in the following example:
Store: frames matching LAVc_all
or Distrib_Enable
or Distrib_Trigger
ending with Distrib_Trigger
Log file: not used
Block 1: Wait_for_distributed_enable
When frame matches Distrib_Enable then go to block 2
Block 2: Wait_for_the_event
When frame matches LAVc_TR_ReXMT then go to block 3
Block 3: Send the distributed trigger
Mark frame
and then
Send message Distrib_Trigger
The scribe program waits for the distributed enable and then captures all of
the LAN traffic and terminates as a result of the distributed trigger. The scribe
program allows a network manager to capture data at about the same time as
when the retransmitted packet was detected on another segment. After the data
capture has completed, the data from multiple LAN segments can be reviewed to
locate the initial copy of the data that was retransmitted. The scribe program is
shown in the following example:
F–34 Troubleshooting the NISCA Protocol