ODROID-H2/H3 Net Card

The ODROID Net card brings 4 additional 2.5 GbE Ethernet ports for an incredible low price. It is compatible with the H2, H2 rev. B, H2+, H3 and, H3+. Using a H2+/H3/H3+ you end up with a total of 6 x 2.5 GbE Ethernet ports. With the H2 and H2 rev. B you get 2 x 1 GbE and 4 x 2.5 GbE Ethernet ports.

The ODROID H2/H2+/H3/H3+ with the ODROID H2/H3 Net card brings new capabilities and applications. Examples (non-exhaustive list):

• Implementing a DIY router or gateway for up to 5 (H2/H2 rev. B) clients at 2.5 GbE speed on each port.
• Setup a DIY server, e.g. a NAS, for up to 6 (H2+/H3/H3+) clients at 2.5 GbE speed on each port.
• Brings 2.5 GbE Ethernet connectivity to the H2 and H2 rev. B boards making them able to talk at full speed (usually 2.35 Gbits/sec) with H2+/H3/H3+ boards.

• Schematics
• AutoCAD top
• AutoCAD bottom

While the M.2 slot is primarily intended to be used with a NVMe PCIe x4 SSD it can alternatively be used to plug in a PCIe card like graphics cards, IO cards, network cards, etc. Our users use a M.2 to PCIe cable adapter to do so. You can buy these cables from 3rd party vendors or Hard Kernel products distributors (e.g. https://ameridroid.com/collections/new/products/m-2-to-pcie-adapter-straight).

The H2/H3 Net Card connects to the H2/H2+/H3/H3+ board using the M.2 slot to leverage the PCIe x4 lanes. The H2/H3 Net Card expects the M.2 slot to provide 4 bifurcated x1 lanes. However, the default M.2 slot configuration provides 1 non-bifurcated x4 lane by default.

The M.2/PCIe slot lanes bifurcation is configured in the ESF BIOS itself.

Flashing the H2/H2+/H3/H3+ BIOS with the bifurcated version and installing the H2/H3 Net card changes the PCIe buses configuration. Consequently you need to reconfigure your Ethernet ports accordingly.

On Linux for instance:

• With the non-bifurcated M.2 BIOS and without the H2/H3 Net card the two onboard Ethernet ports show up as enp2s0 and enp3s0.
• With the bifurcated M.2 BIOS and the H2/H3 Net card plugged in, the card 4 Ethernet ports show up as enp1s0, enp2s0, enp3s0 and enp4s0 and the two onboard NICs show up as enp5s0 and enp6s0.

To measure the network throughput with iperf3 we prepared six H2+ boards. One H2+ has a H2+ Net card (thus 6 x 2.5 GbE ports) the five others have 2 x 2.5 GbE ports. One port on each of the five H2+ is connected to a port on the H2+ with the H2+ Net card. Each IP connection is defined on a separate sub-net so that the internal routing (Windows and Linux) will use each connection independently from the others.

The five H2+ ran iperf3 as servers receiving data (iperf3 -s …). The H2+ with the H2+ Net card ran iperf3 as client sending data (iperf -c …).

Sending mode (iperf -c …) corresponds to a real world usage where 5 “clients” are reading data from the H2+ with the H2+ Net card, e.g. 5 clients copying file(s) from the same NAS.

Receiving mode (iperf -c … -R) corresponds to a real usage situation where 5 “clients” are sending data to the H2+ with the H2+ Net card, e.g. 5 clients copying file(s) to the same NAS.

The difference with real usage situations is that iperf3 does nothing with the data on the receiver side, no disk IO involved for instance: iperf3 only measures network throughput at the Internet Protocol (IP) level.

See photos shown below.

The inxi output shown below correctly reports the 6 x 2.5 GbE ports on the H2+ with the H2+ Net card, the ports being driven by the Realtek r8125 v9.003.05 driver.

In other words, the H2+ with the H2 Net card includes:

• an Intel Celeron J4115 (Odroid-H2+),
• the Hardkernel Odroid-H2 1.22 BIOS (M.2 slot configured as 4 bifurcated x1 lanes ),
• a Ubuntu 20.04.1 + 5.4.0-56 Kernel (running on a 64GB eMMC module),
• two Samsung DDR4 2400MHz 16GB in dual channel,
• two built-in 2.5GbE and four additional 2.5GbE from the Net card. Total six 2.5 GbE NICs configured with the Realtek r8125 9.003.05 driver to get the best performance in multi-sessions.

Once the five other H2+ run iperf3 -s …, making them able to receive data, we can run multiple sessions on the H2+ with the H2+ Net card as displayed in the screenshot shown below. Note that the sessions running in parallel are all cruising at 2.35 Gbits/sec :)

Let us now look at the results measuring 1, 2, 3, 4 and 5 parallel sessions. We measured the network throughput (Mbps) and CPU usage (%) on the H2+ with the H2 Net card.

The measurements were made with 1 session alone for about 30 seconds, then started a 2nd session while the 1st session continued, then started a 3rd session while the two previous sessions continued and so on up to running 5 parallel sessions. As a result the network throughput (red line) has a staircase look and the CPU usage (blue line) follows the same pattern with a jagged line.

In Sending mode the testing consumes up to 45% of the H2+ with the H2 Net card CPU resources with five 2.5 GbE iperf3 sessions, about 9% per session. All of the sessions show a solid 2.35 Gbits/sec network throughput.

In Receiving mode the testing consumes up to 75% of the H2+ with the H2 Net card CPU resources with five 2.5 GbE iperf3 sessions, about 15% per session. All of the sessions show a solid 2.35 Gbits/sec network throughput.

A H2+ with the H2 Net card gladly handles more than 11 Gbits/sec total. Due to this rough upper limit, it’s only when running SIX parallel sessions that the throughput declines under 2.35 Gbits/sec per session.

A H2+ can therefore provide excellent support for parallel clients with enough remaining CPU resources to proceed with computation and disk IO.

In other words, the H2 Net card brings significant added value to a H2/H2+-based NAS or Router/Gateway solution where parallel clients can enjoy the full 2.5 GbE speed independently from each other. Especially to H2 and H2 rev. B which don’t have onboard 2.5 GbE connectivity in the first place!

All with a very low cost network card :)

Samba is available on all the major Linux distributions and supports the SMB/CIFS protocol (used on Windows for file sharing) as well as Active Directory. Samba is the major protocol for Linux-based networked file servers also known as NAS (Network Attached Storage). Using Samba on Linux is a very low-cost way to share files between Windows, Linux and Mac OS clients. Linux + Samba is the tool of choice for creating DIY NAS appliances at home in SOHO environment, start-ups and small businesses.

To measure the performance of the H2 Net card with Samba we setup the following sub-net:

• One H2+ with Net Card running Linux,
• Another H2+ running Windows 10,
• A laptop also running Windows 10.

The two machines running Windows 10 are the clients. Because motherboards with an onboard 2.5 GbE NIC are still a small percentage of the market (expensive top tier motherboards), we decided to run our testing with USB 3 Gen 1 2.5 GbE USB adapters sporting a Realtek RTL RTL8156B chipset on both clients. These USB adapters can be used on any motherboard or SBC with at least one USB 3 Gen 1 port.

See photo of the connected test machines shown below.

The inxi output shown below correctly reports the 6 x 2.5 GbE ports on the H2+ with the H2+ Net card, the ports being driven by the Realtek r8125 v9.003.05 driver.

The H2+ with the H2 Net card, which is in our testing the Linux/Samba-based NAS, includes:

• an Intel Celeron J4115,
• the Hardkernel Odroid-H2 1.22 BIOS (M.2 slot configured as 4 bifurcated x1 lanes),
• a Ubuntu 20.04.1 + 5.4.0-56 Kernel running on a 64GB eMMC module,
• two Seagate Barracuda 2TB HDD for data storage,
• two Samsung DDR4 2400MHz 16GB in dual channel,
• two built-in 2.5GbE and four additional 2.5GbE from the H2 Net card. Total six 2.5 GbE NICs configured with the Realtek r8125 9.003.05 driver to get the best performance in multi-sessions.

The first Windows 10 client (Odroid-H2+) includes:

• an Intel Celeron J4115,
• the Hardkernel Odroid-H2 1.22 BIOS (M.2 slot configured as 1 x4 lanes, not important for this test),
• Windows 10 20H2 running on a 128GB eMMC module,
• Two Samsung DDR4 2400MHz 16GB RAM
• An RTL8156B-based 2.5 GbE USB 3 Gen 1 adapter (with Realtek driver)

The second Windows 10 client (laptop) includes:

• an Intel Core i7-7500U
• Windows 10 1909 running on an internal 128GB SSD
• Onboard DDR4 4GB RAM + Samsung DDR4 2400MHz 16GB RAM
• An RTL8156B-based 2.5 GbE USB 3 Gen 1 adapter (with Realtek driver)

We set static IP addresses on the 2.5 GbE NICs using two different sub-nets on the clients:

• First Windows 10 client USB adapter: 192.168.3.100/24
• Second Windows 10 client USB adapter: 192.168.4.100/24

We accordingly set static IP addresses on the server NICs as shown below:

• Server NIC connected to first Windows 10 client: 192.168.3.40/24
• Server NIC connected to second Windows 10 client: 192.168.4.40/24

Because we use two different sub-nets with network mask 24, the server Linux kernel routing table is correctly automatically set:

• Anything transmitted between the server and the first Windows 10 client will go through the 192.168.3.0/24 sub-net
• Anything transmitted between the server and the second Windows 10 client will go through the 192.168.4.0/24 sub-net

A similar automatic routing is performed by the Windows kernel on each client.

In other words, simultaneous communication between the server and the two clients will happen on the respective NICs and provide 2.35 Gbits/sec for each client as we have seen with the iperf3 performance test (see previous section) no matter what the other client is doing.

On the server side, we edit the Samba configuration as shown below:

odroid@ODROID-H2Plus:~$ testparm
...
 
[H2P-HDD1]
        create mask = 0755
        path = /mnt/hdd1
        read only = No
        valid users = odroid
 
 
[H2P-HDD2]
        create mask = 0755
        path = /mnt/hdd2
        read only = No
        valid users = odroid

Windows 10 includes a driver to handle most of the Realtek network chipset. However this built-in driver may not contain the right code and settings for the new RTL8156B chipset. As a result you may witness inconsistent speed or behavior as it appears in the screenshot shown below where the sending speed using iperf3 is an expected 2.33 Gbits/sec while the receiving speed is a pretty sad 170 Gbits/sec.

In the iperf3 test, this only shows up to 200 Mbps in download bandwidth.

To fix this issue (as well as others), we downloaded the driver from the Realtek website: https://www.realtek.com/en/component/zoo/category/network-interface-controllers-10-100-1000m-gigabit-ethernet-usb-3-0-software

Once the driver has been installed, iperf3 shows 2.3x Gbits/sec in both sending and receiving modes, which is what is to be expected.

The H2 Net card brings significant added value to a H2/H2+-based NAS solution where simultaneous clients can enjoy the full 2.5 GbE speed independently from each other, especially to H2 and H2 rev. B which don’t have onboard 2.5 GbE connectivity in the first place!