Bandwidth Guarantees for Telecom Services using SR-IOV and Containers
Fri, 12 Mar 2021 16:29:21 -0000|
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With the emergence of Container-native Virtualization (CNV) or the ability to run and manage virtual machines alongside container workloads, Single Root I/O Virtualization (SR-IOV) takes on an important role in the Communications Industry. Most telecom services require guarantees of capacity e.g. number of simultaneous TCP connections, or concurrent voice calls, or other similar metrics. Each telecom service capacity requirement can be translated into the amount of upload/download data that must be handled, and the maximum amount of time that can pass before a service is deemed non-operational. These bounds of data and time must be met end-to-end, as a telecom service is delivered. The SR-IOV technology plays a crucial role on meeting these requirements.
With SR-IOV being available to workloads and VMs, Telecom customers can divide the bandwidth provided by the physical PCIe device (NICs) into virtual functions or virtual NICs. This allows the virtual NICs with dedicated bandwidth to be assigned to individual workloads or VMs ensuring SLA agreements can be fulfilled.
In the illustration above, say we have a 100GB NIC device that is shared amongst workloads and VMs on a single hardware server. The bandwidth on a single interface is typically shared amongst the workloads and VMs as shown for interface 1. If one workload or VM is extremely bandwidth hungry it could consume a large portion of the bandwidth, say 50%, leaving the other workloads or VMs to share the remaining 50% of the bandwidth which could impact the SLAs agreements under contract the Telco customer.
To ensure this doesn’t happen the specification for SR-IOV allows the PCIe NIC to be sliced up into virtual NICs or VFs as shown with interface 2 above. Slicing the NIC interface into VFs, one can specify the bandwidth per VF. For example, 30GB bandwidth could be specified for VF1 and VF2 for the workloads while VF3–5 could be allocated the remaining bandwidth divided evenly or perhaps only give 5GB each leaving 15GB for future VMS or workloads. By specifying the bandwidth at the VF level, Telco companies can guarantee bandwidths for workloads or VMs thus meeting the SLA agreement with their customers.
While this high-level description of the mechanics illustrates how you enabled the two aspects: SR-IOV for workloads and SR-IOV for VMs, Dell Technology has a white paper, SR-IOL Enablement for Container Pods in OpenShift 4.3 Ready Stack, which provides the step-by-step details for enabling this technology.