iSCSI over Data Center Bridging (DCB) interoperability testing verifies the functionality of the DCB protocol when integrated with iSCSI traffic among a set of devices from a variety of vendors. Throughout the testing process, several device topologies are incorporated to observe behavior in a collection of scenarios. Since the technology is still in a relatively early stage, the protocols defining its implementation are subject to change. As a result, this creates a small set of complications that must be addressed in order to successfully carry out the testing procedure.
Conflicting implementations of Data Center Bridging Exchange DCBX contribute to the complications of interoperability testing; while some vendors implement baseline DCBX, others implement IEEE DCBX. Still, others either conglomerate these versions to allow for universal DCBX compatibility, or base the version of DCBX used on the DCBX frames. As such, particular devices may be unable to negotiate with each other due to differing implementations. To circumvent this issue, a DCBX configuration is decided upon and is to be applied to all devices so that the lack of an automated negotiation process does not detract from the ability to carry out interoperability testing.
Many devices are set to only allow local configuration changes, thus preventing negotiation between devices maintaining incongruous configurations. Due to an unwilling state of change for relevant attributes of Data Center Bridging, such configurations must be manually applied to the device. Since testing progresses and configuration changes must be made to reflect the differing bandwidth allocations being used, each change must be applied to all devices set to an unwilling state, adding an additional layer of complexity to the testing procedure.
Interoperability testing provides the opportunity to witness iSCSI over DCB at work from a collection of conformance-compliant vendors. With that opportunity brings the complications of DCBX incompatibility and ineffective automated negotiation. These complications allow for greater insight into the intricacies of individual devices and the Data Center Bridging technology as a whole.
Daniel Shea, Research and Development