OSA-Express network traffic analyzer trace

When data problems occur in a network with OSA adapters, multiple traces are usually required. A sniffer trace might be required to see the data as it was received from or sent to the network, an OSA hardware trace might be required if the problem is suspected in the OSA, and z/OS® Communications Server traces are required to diagnose VTAM® or TCP/IP problems.

To help with problem diagnosis, the OSA-Express® network traffic analyzer (OSAENTA) function provides a way to trace inbound and outbound frames for an OSA-Express2 or later feature in QDIO mode. The OSAENTA trace function is controlled and formatted by z/OS Communications Server, but is collected in the OSA at the network port. You can control the OSAENTA trace function by using either the OSAENTA statement in the TCP/IP profile or the VARY TCPIP,,OSAENTA command. The controls that are provided include the ability to filter what data is collected by parameters such as IP address, TCP/UDP port, or frame type, and to specify how much data is to be collected. They also provide the capability to trace frames that are discarded by the OSA-Express2 or later feature. You can display current settings for the OSAENTA trace function by using the Netstat DEvlinks/-d command.

Because the data is collected at the Ethernet frame level, you can use this function to trace the MAC headers for packets, a capability that is not provided by existing packet traces. It also enables the tracing of other types of packets that existing packet traces do not contain, including the following packets:

There are obvious security considerations for this type of trace. Security control is enabled at the Hardware Management Console (HMC) of the OSA-Express2 or later feature. To trace packets for stacks or images other than the operating system image where you activate the OSAENTA trace interface, you must use the HMC to configure the OSA to enable this tracing.

The OSAENTA trace function communicates with the OSA-Express feature being traced by using a dynamically defined QDIO interface to the OSA-Express feature. The interface is created when the first VARY TCPIP,,OSAENTA command for that OSA is entered, or the first OSAENTA TCP/IP profile statement is processed. The interface is named EZANTAxxxxxxxx, where xxxxxxxx is the port name of the OSA specified on the VARY TCPIP,,OSAENTA command, and must match the PORTNAME parameter on the VTAM TRLE representing the traced OSA-Express feature. This also means that a TRLE must be defined in VTAM for this OSA-Express trace interface, though the same TRLE used for MPCIPA devices and interfaces is used for this dynamically defined trace interface. The EZANTAxxxxxxxx interface is used exclusively for receiving trace records from that OSA-Express feature. It is started, stopped, and deleted with the ON, OFF, and DEL parameters of the VARY TCPIP,,OSAENTA command.

When the OSAENTA trace is enabled, the received trace records are collected by Component Trace (CTRACE) using the SYSTCPOT component. The traced records can then be formatted using the IPCS CTRACE command, specifying the component name SYSTCPOT. For information about retrieving the OSA-Express network traffic analyzer data in real time, see z/OS Communications Server: IP Programmer's Guide and Reference.

The OSAENTA trace can have a negative impact on performance if sufficient trace filters are not specified before you enable the trace. OSAENTA can reduce the amount of traffic that the OSA-Express feature can process and the amount of traffic that can be accelerated through that OSA-Express feature. Also, host processing to collect the OSAENTA trace records can increase host CPU consumption. Specify sufficient filters to limit the amount of traffic that is traced to only what is necessary for problem diagnosis.

For more information about the OSAENTA statement, see z/OS Communications Server: IP Configuration Reference. For more information about the VARY TCPIP,,OSAENTA command, see z/OS Communications Server: IP System Administrator's Commands. For more information about formatting an OSAENTA trace, see z/OS Communications Server: IP Diagnosis Guide. For the level of OSA-Express2 or later feature that supports OSAENTA, see the 2094DEVICE Preventive Service Planning (PSP) bucket and the 2096DEVICE Preventive Service Planning (PSP) bucket.

Parent topic: Considerations for networking hardware attachment