Using Multiple RDMA Cameras on a Switch

Introduction

By properly configuring the bandwidth sharing among multiple RDMA cameras, you can avoid frame drops. This document will guide you on how to effectively use multiple 10G RDMA cameras on a 10G switch.

Prerequisites

Software: Arena SDK v1.0.44.11 or newer
Firmware: Contact support@thinklucid.com
10G switch, including 10G upstream to host NIC

RDMA 10GigE Cameras using a Network Switch

Equipment Used

2x ATX051S
2x ATX162S
LUCID PCIE-10GPOE2-LUCID
4x CAB-MR-5M-A
4x M8P-US1
Switches used:
- TP Link TL-SX1008, or
- FS S3950-4T125-R with 4x 10Gtek ASF-10G-T

Setup

Scenario 1: 2.5Gbps per camera

Camera	ATX051S-CC	ATX051S-MC	ATX162S-CC	ATX162S-MC
Device Link Speed	1250000000 Bps	1250000000 Bps	1250000000 Bps	1250000000 Bps
Width	2448	2448	5320	5320
Height	2048	2048	3032	3032
Pixel Format	BayerRG8	Mono8	BayerRG8	Mono8
ADC Bit Depth	12-bit	12-bit	12-bit	12-bit
Packet Size	4144	4144	4144	4144
Packet Delay	80	80	80	80
Device Link Throughput Reserve	10%	10%	10%	10%
Transport Stream Protocol	RDMA	RDMA	RDMA	RDMA
Device Link Throughput Limit Mode	On	On	On	On
Acquisition Frame Rate Enable	True	True	True	True
Acquisition Frame Rate	59.5	59.5	18.5	18.5

Each camera’s bandwidth is limited by configuring the following settings:

Device Link Throughput Limit Mode = On
Acquisition Frame Rate Enable = True
Acquisition Frame Rate value set up to allow ~2.38Gbps per camera

Because the switch connection to the host PC uses one 10GigE connection, these settings ensure that the four cameras can stream to the switch while efficiently sharing available bandwidth with other cameras.

You can calculate the approximate bandwidth in your current settings with the following formula:

= (width) x (height) x (bytes per pixel) x (frame rate)

=  2448   x   2048   x   1               x  59.5
   width     height      8 bits per pixel   frames per second
                       = 1 byte

= 298303488 Bytes per second
= 298303488 / (1 Byte / 8 bits)
= 298303488 / 0.125
= 2386427904 bits per second (2.3 gigabits per second)

Scenario 2: 5Gbps for 1 camera, 1.6Gbps for 3 cameras

Camera	ATX051S-CC	ATX051S-MC	ATX162S-CC	ATX162S-MC
Device Link Speed	1250000000 Bps	1250000000 Bps	1250000000 Bps	1250000000 Bps
Width	2448	2448	5320	5320
Height	2048	2048	3032	3032
Pixel Format	BayerRG8	Mono8	BayerRG8	Mono8
ADC Bit Depth	12-bit	12-bit	12-bit	12-bit
Packet Size	4144	4144	4144	4144
Packet Delay	80	80	80	80
Device Link Throughput Reserve	10%	10%	10%	10%
Transport Stream Protocol	RDMA	RDMA	RDMA	RDMA
Device Link Throughput Limit Mode	On	On	On	On
Acquisition Frame Rate Enable	True	True	True	True
Acquisition Frame Rate	38.5	12.0	39.5	39.5

Remember to divide the bandwidth per camera so that the overall bandwidth delivered to the switch is not over 10G.

Conclusion

Adjusting the total bandwidth for the RDMA-enabled 10GigE cameras to stay within the connection bandwidth between the switch and the host PC allows multiple 10GigE cameras to utilize RDMA data streaming through a switch. This configuration ensures that the cameras stream through the network switch without encountering packet collisions or risking frame drops.