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Virtual routing and forwarding

About virtual routing and forwarding

You can use virtual routing and forwarding (VRF) to provide multi-tenancy functionality. For example, where each tenant has its own unique routing tables and requires different default gateways.

VRF reduces the number of permissions needed by cloud-native network function (CNF), and provides increased visibility of the network topology of secondary networks. VRF devices combined with IP address rules provide the ability to create virtual routing and forwarding domains.

Processes can bind a socket to the VRF device. Packets through the binded socket use the routing table associated with the VRF device. An important feature of VRF is that it impacts only OSI model layer 3 traffic and above so L2 tools, such as LLDP, are not affected. This allows higher priority IP address rules such as policy-based routing to take precedence over the VRF device rules directing specific traffic.

Benefits of secondary networks for pods for telecommunications operators

You can connect network functions to different customers' infrastructure by using the same IP address with the Container Network Interface (CNI) virtual routing and forwarding (VRF) plugin. Using the CNI VRF plugin keeps different customers isolated.

In telecommunications use cases, each CNF can potentially be connected to many different networks sharing the same address space. These secondary networks can potentially conflict with the cluster’s main network CIDR.

With the CNI VRF plugin, IP addresses are overlapped with the OKD IP address space. The CNI VRF plugin also reduces the number of permissions needed by CNF and increases the visibility of the network topologies of secondary networks.