I covered Multus in a previous blog – https://www.vamsitalkstech.com/5g/why-5g-implementations-will-need-a-meta-cni-aka-multus/. However, given that this comes up a lot in customer conversations, I thought it would be best to clarify the popular telco-grade plugins and their overall role.
Multus, SR-IOV, and DPDK are three different technologies that are commonly used in the field of networking and virtualization. While they all have some similarities, there are some significant differences between them:
Multus
Multus is a Kubernetes CNI (Container Network Interface) plugin that enables the creation of multiple network interfaces in a single pod. This means a pod can have multiple network interfaces, each with its IP address and routing table. This is useful in scenarios where a pod needs to communicate with different networks or have different network policies for different traffic flows. Multus is a “meta-CNI” that provides the ability to create multi-homed Kubernetes pods. By default, Kubernetes only lets you connect one interface to each pod. However, Multus lets you connect multiple interfaces to the same pod. This is important for telco networking where all sorts of complex scenarios occur.
SR-IOV
SR-IOV (Single Root I/O Virtualization) is a technology that enables the (virtual) division of a single physical network interface card (NIC) card into multiple virtual functions (VFs). Each of these virtual NICs has its own MAC address and network identity. So, each VF is then assigned to an individual virtual machine (VM) and looks (and behaves) as a separate physical NIC to the VM. This enables the VM to have direct and independent access to the hardware resources of the physical NIC (as it doesn’t have to go through the host hypervisor), thus improving network performance and reducing CPU overhead.
DPDK
So DPDK (Data Plane Development Kit) is a set of drivers and libraries that allow for fast packet processing in network applications. DPDK works in the host space, so users must install the necessary libraries and turn on interfaces using “dpdk-bind.” When used together, Multus enabled DPDK-enabled interfaces on the host to be utilized within Kubernetes pods by exposing the interfaces to the pods via a plugin called “host-device”. This moves the interfaces from the host space to the container, making it possible to connect multiple network interfaces to a single pod.
Using Multus and DPDK together, you can create pods with multiple network interfaces, some of which are backed by DPDK. This lets you take advantage of the speed benefits of DPDK and the flexibility of Multus, which lets you connect multiple interfaces to a single pod.
Conclusion
In summary, while all three technologies are related to networking and virtualization, they have different use cases and capabilities. Multus enables the creation of multiple network interfaces within a pod, SR-IOV enables direct access to hardware resources for VMs, and DPDK provides high-performance packet processing.
Featured Image by Benjamin Wiens from Pixabay