Interfaces and OSA use cases

The Interfaces and OSA workspaces were created to facilitate investigation of the following issues.

These use cases address the navigation paths shown in Figure 1.
Figure 1. Interfaces and OSA navigation paths
Interfaces and OSA navigation paths

Congested OSA interface

A systems programmer needs to identify quickly whether one OSA is processing a significantly greater amount of traffic than the other OSA on the same LPAR. Traffic should be evenly distributed between the two OSA ports. The systems programmer does the following:

  1. He navigates to the Enterprise OSA Interfaces Overview workspace.
  2. He views the OSA Interface Status subpanel to ensure that the Interface Status is Active.
  3. He reviews the values in the OSA Interface Statistics subpanel for the Transmit Packet Rate and Receive Packet Rate and determines that one OSA is transmitting and receiving significantly more traffic than the other OSA.
  4. He issues a D TCPIP OMP RTTABLE command to display the main OMPROUTE table and determines the first hop switches are congested for the non-productive OSA adapters.
  5. He contacts networking support.

Inbound traffic not flowing

A systems programmer needs to determine if an OSA is down, an OSA has a throughput issue, or there is a problem with a physical switch. Two OSA ports provide network connectivity to each LPAR. The systems programmer has no visibility to the network, and the network administrators have no visibility to the mainframe. ICMP is not turned on by default due to firewall issues. To do this, the system programmer stops traffic going through one of the two default OSA adapters and then forces traffic through the other to determine if one of them is down or has a throughput issue. The systems programmer does the following:

  1. She navigates to the Enterprise Interfaces Overview workspace.
  2. She views the Interface Status subpanel to ensure that the Interface Status value is Active.
  3. She views the Interface Errors subpanel and ensures that there are no packets in error or Inbound Packets Discarded.
  4. She views the Interface Statistics subpanel and identifies an interface with a low Bytes Received and Receive Packet Rate and suspects that the OSA for this interface is experiencing throughput issues.
  5. She stops traffic flowing to this OSA and forces traffic through a different OSA and then reverses the procedure.
  6. She confirms that one OSA is experiencing throughput issues and contacts networking support.

Low OSA channel path utilization

A systems programmer needs to determine at-a-glance if channel path utilization is evenly distributed across all channel paths or if one channel path has less utilization than the others. The systems programmer does the following:

  1. He navigates to the Enterprise OSA-Express Channels Overview workspace.
  2. He sorts on the Processor Utilization per Hour attribute and determines that channel path utilization is not evenly distributed across all channel numbers (Channel Number is defined as the CHPID corresponding to this device).
  3. By viewing the System ID, he determines that the channel paths with low utilization reside on a different central electronic complex (CEC).
  4. He moves the TN3270 servers from one CEC to another CEC to increase the channel path utilization of the less-used OSA channels.