Virtual LAN (VLAN) | Holoscan Sensor Bridge Documentation

Holoscan Sensor Bridge (HSB) IP supports IEEE 802.1Q VLAN tagging. VLAN tagging can be used to prioritize network traffic by Priority Code Point (PCP) field and logically separate traffic using Virtual IDs (VID).

IEEE 802.1Q VLAN tagging can be used with Time Sensitive Networking (TSN) capable switch to deterministically shape the network traffic. TSN requires both IEEE 802.1Q VLAN tagging and IEEE 802.1AS gPTP synchronization. To configure the Host and HSB to gPTP profile and VLAN subinterface, refer to TSN IMX274 example.

Data-plane VLAN behavior

Each data-plane sensor virtual port can be configured to be VLAN tagged or untagged and with its own PCP and VID values. 3-bit PCP field is used to shape the dataplane traffic, for example, all camera sensors can be set to a certain PCP value and IMU sensors to a different PCP value to group the sensor types.

Refer to TSN Configuration Sequence to configure the sensor data-plane with a VLAN tag.

Control-plane VLAN behavior

Control-plane VLAN behavior varies for different types.

For example, BOOTP packets are always untagged so the host can always enumerate the HSB on the network.

For ARP, PING, ECB packets, Host is the initiator and HSB is the responder so the HSB adapts to the packet it received. If the host sends untagged ECB packet, the HSB will respond with untagged ECB packet, if the Host sends tagged ARP packet, the HSB will respond with the same VLAN tag.

Description of each control-plane packet and its VLAN behavior is listed below.

Traffic	VLAN on wire
ARP, PING, ECB	Adaptive If the host sends a VLAN-tagged frame, the HSB stores that tag and responds with the same 802.1Q tag. If the host sends untagged traffic, responses are untagged. No VLAN ID / PCP / enable register programming is required for control plane.
Control events	Register programmed as part of the TSN configuration sequence.
PTP	Untagged only gPTP/PTP frames are always sent and received without an 802.1Q tag.
BOOTP (enumeration)	Untagged TX The HSB transmits untagged BOOTP enumeration. Host enumeration listens on the parent interface or configured BOOTP bind device accordingly.