z/VM Virtual Networking Tip - Using SNMP

You can use SNMP to manage virtual switches with z/VM 5.3.0. Follow these steps to prepare your z/VM system.

  1. Define a manager for the virtual switch by adding the "VSWITCH vswitchnm" option to a HOME statement in a z/VM TCP/IP stack.

    Use the NETSTAT HOME or the QUERY VSWITCH command to confirm that the IP address you have selected is successfully established as the virtual switch manager.

  2. If necessary configure SNMPD and SNMPSUBA user IDs for your stack, as described in "Configuring SNMP Servers" in the z/VM TCP/IP Planning and Customization book.

  3. Make sure the sample MIB_EXIT SDATA file is renamed to MIB_EXIT DATA.

  4. Add entries to the SNMPTRAP DEST file to define one or more places to which traps are sent. LINK UP and LINK DOWN traps are sent whenever the status of a guest link or virtual switch network connection (RDEV) changes.

From an SNMP client use the VSWITCH management IP address to display MIB information for the virtual switch. Bridge MIBs supported for virtual switches include:

  • The dot1dBase tree. This describes the bridge (virtual switch) attributes. and includes a dot1dBasePortTable providing information such as the port number and interface index for each port. For a z/VM virtual switch, port numbers 1-8 represent the OSA-E connections to the LAN segment. Port numbers starting at 65 represent guests coupled to the virtual switch.

  • The dot1dTp tree. This includes the dot1dTpFdbTable which shows MAC addresses associated with the virtual switch, and the dot1dTpPortTable which displays the traffic counts (frames in and out, and discards) for each port.

This document is maintained by: 

Montana Lee
z/VM Development
montanalee@ibm.com