Configuring SR Linux for P4Runtime

To configure SR Linux for P4Runtime, you perform the following configuration tasks:

Configure a TLS profile to secure communication with P4Runtime clients. See the SR Linux Configuration Basics Guide for information about configuring TLS profiles.
Configure interface identifiers. To allow P4Runtime clients to reference specific interfaces in PacketIn and PacketOut messages, you configure per-interface identifiers consisting of a port ID and device ID. See Identifying interfaces to P4Runtime.
Configure settings for the P4Runtime server, including idle timeout, session limits, and connection rate limiting. See Configuring P4Runtime server settings.
Configure UNIX-socket specific settings for the P4Runtime server. See Configuring the P4Runtime server for UNIX sockets.
Configure service authorization for the p4rt interface type. See "Service Authorization" in the SR Linux Configuration Basics Guide.

Identifying interfaces to P4Runtime

The PacketIn and PacketOut messages within the P4Runtime StreamChannel RPC require that the interface a packet is received on or transmitted out of be uniquely identified. To do this, you configure a unique per-interface identifier, which is a tuple consisting of the following:

A chassis-unique port identifier (known as the interface_id). This identifier can be manually configured, or if it is not, the system ifIndex for the interface is used by default.
A chassis-unique device identifier that indicates the specific line card and ASIC with which the port is associated (known as the device_id)

For example, to identify interface ethernet 1/1 to P4Runtime, you can configure the interface_id for the ethernet 1/1 port, and configure a device_id identifying the line card and ASIC associated with the ethernet 1/1 port.

The P4Runtime client uses a lookup table consisting of the device_id,interface_id tuple → interface-name (as specified by the device) to translate where packets are to be sent to, or populate where a packet was received.

Configuring a port identifier for P4Runtime

The interface_id part of the device_id,interface_id tuple uniquely identifies a port in the SR Linux chassis to a P4Runtime client. You can configure the value for interface_id. If you do not configure a value for interface_id, the port's ifIndex value is used by default.

--{ candidate shared default }--[  ]--
# info interface ethernet-1/1 p4rt
    interface ethernet-1/1 {
        p4rt {
            id 2002
        }
    }

Configuring a device identifier for P4RT

The device_id identifies a specific line card and ASIC in the chassis. P4Runtime uses the combination of the device_id and interface_id to identify the specific interface that a packet was received on (in PacketIn messages). Note that for identifying the interface that a packet is to be sent via (in PacketOut messages), only the interface_id is used.

There is no default device_id for a line card / ASIC; you must configure the device_id value to be used by P4Runtime.

--{ candidate shared default }--[  ]--
# info platform linecard 1 forwarding-complex 0
    platform {
        linecard 1 {
            forwarding-complex 0 {
                p4rt {
                    id 10001
                }
            }
        }
    }

Configuring P4Runtime server settings

You can configure settings for the specified P4Runtime server. These settings apply to the specified network-instance where the P4Runtime server is enabled, and to UNIX sockets if enabled. You can configure the following:

Whether to administratively enable the P4Runtime server
Limit the number of connection attempts per minute by P4Runtime clients
Limit the number of P4Runtime RPC connections that can be active at one time
Idle-timeout in seconds for P4Runtime clients
The network instance on which to administratively enable the P4Runtime server
The gRPC service to enable; in this case, p4rt
The port the P4Runtime server listens to for the network-instance. By default, this is TCP port 57400.
IP addresses the P4Runtime server listens on within the network-instance
TLS profile to secure communication between P4 Runtime clients and SR Linux for the network-instance
Whether username/password authentication is used for each P4Runtime RPC request
gRPC trace options ([common | grpc | request | response])
The YANG models to use when the origin field is not present in requests (default: native)

--{ candidate shared default }--[  ]--
# info system grpc-server mgmt-test
    system {
        grpc-server mgmt-test {
            admin-state enable
            timeout 14400
            rate-limit 120
            session-limit 40
            metadata-authentication true
            tls-profile tls-profile-1
            network-instance mgmt
            port 9559
            services [
                p4rt
            ]
            source-address [
                192.168.0.1
            ]
        }
    }

Configuring the P4Runtime server for UNIX sockets

You can configure whether to administratively enable the P4Runtime server for UNIX sockets.

The following example configures settings for the P4Runtime server for UNIX sockets:

--{ candidate shared default }--[  ]--
# info system grpc-server mgmt-test
    system {
        grpc-server mgmt-test {
            admin-state enable
            metadata-authentication true
            tls-profile test-tls
            unix-socket {
                admin-state enable
            }
        }
    }

Configuring a chassis ID for the SR Linux device

P4Runtime controllers sometimes model the chassis as a set of IDs, with the chassis having an ID, and each forwarding class having its own ID.

If necessary, you can assign a chassis ID to the SR Linux device. The chassis ID is not used by SR Linux for any purpose; it is intended for use by other controllers that may require a chassis ID on the device.

The following example configures a chassis ID for the SR Linux device:

--{ candidate shared default }--[  ]--
# info platform chassis id
    platform {
        chassis {
            id 2403019611
        }
    }

Disconnecting P4Runtime clients

You can use a tools command to manually disconnect P4Runtime clients from the server.

To do this, get the identifier for the P4Runtime client from the info from state system grpc-server <name> command, then enter the following command to disconnect the client:

-{ running }--[  ]--
# tools system grpc-server mgmt-test client 4053 disconnect