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JCNR Interfaces Overview

SUMMARY This topic provides information on the network communication interfaces provided by the JCNR-Controller. Fabric interfaces are aggregated interfaces that receive traffic from multiple interfaces. Interfaces to which different workloads are connected are called workload interfaces.

Read this topic to understand the network communication interfaces provided by the JCNR-Controller. We cover interface names, what they connect to, how they communicate and the services they provide.

Juniper Cloud-Native Router Interface Types

Juniper Cloud-Native Router supports two types of interfaces:

  • Fabric interfaces—Aggregated interfaces that receive traffic from multiple interfaces. Fabric interfaces are always physical interfaces. They can either be a physical function (PF) or a virtual function (VF). The throughput requirement for these interfaces is higher, hence multiple hardware queues are allocated to them. Each hardware queue is allocated with a dedicated CPU core . The interfaces are configured for the cloud-native router using the appropriate values.yaml file in the deployer helmcharts. You can view the interface mapping using the dpdkinfo -c command (View the Troubleshoot using the vRouter CLI topic for more details). You also have fabric workload interfaces that have low throughput requirement. Only one hardware queue is allocated to the interface, thereby saving precious CPU resources. These interfaces can be configured using the appropriate values.yaml file in the deployer helmcharts.

  • Workload interfaces—Interfaces to which different workloads are connected. They can either be software-based or hardware-based interfaces. Software-based interfaces (pod interfaces) are either high-performance interfaces using the Data Plane Development Kit (DPDK) poll mode driver (PMD) or a low-performance interfaces using the kernel driver. Typically the DPDK interfaces are used for data traffic such as the GPRS Tunneling Protocol for user data (GTP-U) traffic and the kernel-based interfaces are used for control plane data traffic such as TCP. The kernel pod interfaces are typically for the operations, administration and maintenance (OAM) traffic or are used by non-DPDK pods. The kernel pod interfaces are configured as a veth-pair, with one end of the interface in the pod and the other end in the Linux kernel on the host. The DPDK native pod interfaces (virtio interfaces) are plumbed as vhost-user interfaces to the DPDK vRouter by the CNI. JCNR also supports bonded interfaces via the link bonding PMD. These interfaces can be configured using the appropriate values.yaml file in the deployer helmcharts.

    JCNR supports different types of VLAN interfaces including trunk, access and sub-interfaces across fabric and workload interfaces.

JCNR Interface Details

The different JCNR interfaces are provided in detail below:

Agent Interface

The vRouter has only one agent interface. The agent interface enables communication between the vRouter-agent and the vRouter containers. On the vRouter CLI when you issue the vif --list command, the agent interface looks like this:

L3 Fabric Interface (DPDK)

A layer-3 fabric interface bound to the DPDK.

L3 fabric interface in cRPD can be reviewed on the cRPD shell using the junos show interfaces command:

The corresponding physical and tap interfaces can be seen on the vRouter using the vif --list command on the vRouter shell.

L3 Bond Interface (DPDK)

A layer 3 bond interface bound to DPDK.

L3 Pod VLAN Sub-Interface (DPDK)

Starting in Juniper Cloud-Native Router Release 23.2, the cloud-native router supports the use of VLAN sub-interfaces in L3 mode, bound to DPDK.

Corresponding interface state in cRPD:

L3 Pod Kernel Interface

These are non-DPDK L3 pod interfaces. Interface state in the cRPD:

L2 Fabric Interface (DPDK, Physical Trunk)

DPDK L2 fabric interfaces, which are associated with the physical network interface card (NIC) on the host server, accept traffic from multiple VLANs. The trunk interfaces accept only tagged packets. Any untagged packets are dropped. These interfaces can accept a VLAN filter to allow only specific VLAN packets. A trunk interface can be a part of multiple bridge-domains (BD). A bridge domain is a set of logical ports that share the same flooding or broadcast characteristics. Like a VLAN, a bridge domain spans one or more ports of multiple devices.

The cRPD interface configuration using the show configuration command looks like this (the output is trimmed for brevity):

On the vRouter CLI when you issue the vif --list command, the DPDK VF fabric interface looks like this:

DPDK L2 Bond Interface (Active-Standby, Trunk)

Layer-2 Bond interfaces accept traffic from multiple VLANs. A bond interface runs in the active or standby mode (mode 0). You define the bond interface in the helm chart configuration as follows:

The cRPD interface configuration using the show configuration command looks like this (the output is trimmed for brevity):

On the vRouter CLI when you issue the vif --list command, the bond interface looks like this:

DPDK L2 Pod Interface (Virtio Trunk)

The trunk interfaces accept only tagged packets. Any untagged packets are dropped. These interfaces can accept a VLAN filter to allow only specific VLAN packets. A trunk interface can be a part of multiple bridge-domains (BD). A bridge domain is a set of logical ports that share the same flooding or broadcast characteristics. Like a VLAN, a bridge domain spans one or more ports of multiple devices. Virtio interfaces are associated with pod interfaces that use virtio on the DPDK data plane.

The cRPD interface configuration using the show configuration command looks like this (the output is trimmed for brevity):

On the vRouter CLI when you issue the vif --list command, the virtio with DPDK data plane interface looks like this:

L2 Pod Kernel Interface (Access)

The access interfaces accept both tagged and untagged packets. Untagged packets are tagged with the access VLAN or access BD. Any tagged packets other than the ones with access VLAN are dropped. The access interfaces is a part of a single bridge-domain. It does not have any parent interface.

The cRPD interface configuration using the show configuration command looks like this (the output is trimmed for brevity):

On the vRouter CLI when you issue the vif --list command, the veth pair interface looks like this:

L2 Pod VLAN Sub-interface (DPDK)

You can configure a user pod with a Layer 2 VLAN sub-interface and attach it to the JCNR instance. VLAN sub-interfaces are like logical interfaces on a physical switch or router. They access only tagged packets that match the configured VLAN tag. A sub-interface has a parent interface. A parent interface can have multiple sub-interfaces, each with a VLAN ID. When you run the cloud-native router, you must associate each sub-interface with a specific VLAN.

The cRPD interface configuration viewed using the show configuration command is as shown below (the output is trimmed for brevity).

For L2:

On the vRouter, a VLAN sub-interface configuration is as shown below:

Related Documentation