OpenVMS Cluster Systems - OpenVMS Systems - HP

Troubleshooting the NISCA Protocol
F.8 Using a LAN Protocol Analysis Program
F.8.2 Multiple LAN Segments
To troubleshoot multiple LAN segments, LAN analyzers must be able to capture
the multicast packets and dynamically enable the trigger function of the LAN
analyzer, as follows:
Step Action
1 Start capturing the data according to the rules specific to your LAN analyzer. Compaq
recommends that only one LAN analyzer transmit a distributed enable multicast packet
on the LAN. The packet must be transmitted according to the media access-control rules.
2 Wait for the distributed enable multicast packet. When the packet is received, enable the
distributed combination trigger function. Prior to receiving the distributed enable packet,
all LAN analyzers must be able to ignore the trigger condition. This feature is required
in order to set up multiple LAN analyzers capable of capturing the same event. Note that
the LAN analyzer transmitting the distributed enable should not wait to receive it.
3 Wait for an explicit (user-defined) trigger event or a distributed trigger packet. When the
LAN analyzer receives either of these triggers, the LAN analyzer should stop the data
capture.
Prior to receiving either trigger, the LAN analyzer should continue to capture the
requested data. This feature is required in order to allow multiple LAN analyzers to
capture the same event.
4 Once triggered, the LAN analyzer completes the distributed trigger function to stop the
other LAN analyzers from capturing data related to the event that has already occurred.
The HP 4972A LAN Protocol Analyzer, available from the Hewlett-Packard
Company, is one example of a network failure analysis tool that provides the
required functions described in this section.
Reference: Section F.10 provides examples that use the HP 4972A LAN Protocol
Analyzer.
F.9 Data Isolation Techniques
The following sections describe the types of data you should isolate when you use
a LAN analysis tool to capture OpenVMS Cluster data between nodes and LAN
adapters.
F.9.1 All OpenVMS Cluster Traffic
To isolate all OpenVMS Cluster traffic on a specific LAN segment, capture all the
packets whose LAN header contains the protocol type 60–07.
Reference: See also Section F.7.2 for a description of the LAN headers.
F.9.2 Specific OpenVMS Cluster Traffic
To isolate OpenVMS Cluster traffic for a specific cluster on a specific LAN
segment, capture packets in which:
• The LAN header contains the the protocol type 60–07.
• The DX header contains the cluster group number specific to that OpenVMS
Cluster.
Reference: See Sections F.7.2 and F.7.5 for descriptions of the LAN and DX
headers.
F–26 Troubleshooting the NISCA Protocol