USB-over-LAN (Network) MultiSeat Guidelines

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Copyright © 2015 Userful Corporation. All rights reserved.
(Updated 2015.09.28)


To return to the Userful MultiSeat main documentation page, click here.


Introduction

With the release of Userful MultiSeat 5.0, Userful introduced an exciting new multiseat solution: Ethernet zero-client multiseat devices (also known as 'USB-over-LAN' or 'network stations').

Network station multiseat configurations have a number of advantages over either multiseat-via-multiple video cards or USB multiseat devices.

  • More Stations on One Host Computer. The number of stations possible with ethernet zero-client multiseat solutions is not limited by the number of PCI slots on the motherboard (for multiple video cards) or the number of USB 2.0 ports on the host computer (for USB multiseat).
  • Stations Can be Much Farther Away From the Host System. Network stations connect through Cat-5e network cabling and can therefore be located up to 100 meters away from the host station via a single cable. Longer distances can be achieved by using active hardware such as repeaters or switches. In contrast, stations using either additional video cards (which use USB-connected input devices) or USB multiseat devices are limited by the maximum length of USB cables (5 meters ideally,less than 30 meters even with daisy-chaining).
  • Easier Scalability and Flexibility for Deployments. By using switches as part of the network, the stations using one host system can be spread among multiple rooms with a minimum of cabling (only a single network cable from host to each switch). New devices can be added to the network without physical access to the host system, simply by plugging a network device into a switch that is part of the LAN.

Troubleshooting USB-over-LAN MultiSeat Systems

Network multiseat devices are generally easy to setup and use, but troubleshooting can be a challenge. Problems can be loosely grouped into two categories:

  1. Transient Issues
    • Can be difficult to reproduce; that is, they do not occur consistently.
    • May be caused by temporary software glitches or isolated problems with the USB-over-LAN devices themselves.
    • Can often be solved by restarting/resetting the device or system.
  2. Persistent Issues
    • May indicate software bugs or hardware problems (either with hardware itself or how it is connected/configured).
    • Are often easy to reproduce.
    • Could require technical expertise to investigate and rectify the issue.

Correcting Transient Issues

If only one or a few individual stations are not operating properly (station not starting, or station won't assign to host), and there is no problem with firmware or network infrastructure (see below), it could be a transient software/hardware problem. Try the following, in order, to rectify the issue:

  1. Reset/restart the device through the Userful Control Center or by issuing this command in the terminal (device must be unassigned first): userful device reset <MAC.address>.
  2. Power off/power on the device.
  3. Physically reset the device, if a physical reset button is available (HP t200 only)
  4. Reboot the computer.
  5. Reset Userful MultiSeat Configuration and reboot.

Investigating Persistent Issues

If problems are persistent and cannot be resolved by rebooting/resetting/restarting the system or device, following the simple steps below can identify many problems with ethernet zero-client multiseat setups.

  1. Check your network cables.
    • Network cabling should be high-quality Cat-5e.
    • Ensure that all network cables are securely plugged in. Examine the connectors and replace any cables with broken latching tabs as these connections can easily be dislodged.
  2. Check that power supplies and USB cables are secure.
    • USB-over-LAN multiseat devices must be used with a power supply. Ensure that the power supply is firmly plugged into a working electrical outlet, and that the power adapter is firmly plugged into the network device. Most models of USB-over-LAN multiseat devices have lights which indicate that a power supply is connected.
    • If mice or keyboards are not working, check to ensure that they are securely plugged into the ports on the network device. Try swapping out input devices to rule out hardware failures (either a defective mouse, keyboard or USB port).
  3. Check your firmware.
    • USB-over-LAN devices contain a chip that is capable of storing a small amount of data; this includes the hostname of the computer that the device is assigned to as well as the device firmware. It is very important to have the right firmware for a given USB-over-LAN device.
    • To find the correct firmware version that should be used with a given supported device, please refer to the compatible network device list.
    • Firmware can be checked for an individual station through the Userful Control Center by looking at Network station details. Alternatively, firmware for all detected stations can be checked through the terminal by running the following command (with sudo or root): userful device check firmware .
    • Instructions for updating device firmware can be found in How to Manage Network Device Firmware.
  4. Make sure that all network devices (the NIC in the host machine, any switches or routers used) are working at optimal capacity.
    • Networks running at less than sufficient speeds can result in intermittent dropping of USB-over-LAN stations and/or performance issues.
    • For more information on network requirements for USB-over-LAN multiseat systems, please see the network guidelines below.
  5. Check the network configuration for transmission delays and packet loss.
    • Ethernet Zero-Client devices must be within 1 millisecond of the host. You can ping the network device from the host to find out what the delay is. Please note that routers can introduce significant (greater than 0.5 ms) delays and should NOT be positioned in the network between the host and any network device.
    • Network devices are sensitive to packet loss. Ping a network device from the host for 60 seconds to determine the percentage of packets lost. If packets are being lost, it can cause ethernet zero-client instability.

If the steps above do not lead to a solution to the issue, please consider reporting the problem to Userful for investigation.

The easiest way to do so is to go to Userful Control Center > Help and Support > Troubleshoot a Problem. This opens a page with links to relevant documentation that will be most helpful in solving a problem, including:

If a problem cannot be solved using Userful's documentation, the next step is to report a problem to Userful.

To report a problem, click the "Report a Problem" link near the bottom of the "Troubleshoot a Problem" page. A new page will open with a simple form to be filled out. When completed and submitted, the information provided will be e-mailed -- along with a selection of debugging information pulled from the computer system logs and files -- to Userful Customer Support.

Common Issues

There are some particular scenarios that can cause problems for administrators; they are described below along with how to resolve these issues.

If USB-over-LAN devices are connected to the network but do not show up in the Userful Control Center...

... it could be because they have been assigned to another host computer, or because the system hostname has been changed.

To check this, and unassign them if this is the case, open a terminal with sudo or root access:

  • Enter the command virtualusbc -S. This will give a list of all network devices found on the network. Any devices assigned to a server will have a hostname in the third column. In the example below, the hostname is mycon.
200|testnet1|mycon|1|1|192.168.126.117|255.255.255.0|F8:0F:41:2A:B3:63|4|3|00|022.203
200|testnet1|mycon|1|1|192.168.126.106|255.255.255.0|F8:0F:41:2A:B3:84|4|3|00|022.203
200|testnet1|mycon|1|1|192.168.126.103|255.255.255.0|F8:0F:41:2A:B3:99|4|3|00|022.203 
  • If any of the devices are assigned to a different host system than the one you are trying to use, unassign them with the command virtualusbc -U <IP>, where <IP> is the device IP address, found in the 6th column in the example above.

If network devices are detected by the Userful Control Center but none will assign to the host...

...it may be due to unsupported characters in the hostname.

In Ubuntu-based Systems
  • As root or using sudo, edit the hostname file with the following command: nano /etc/hostname
  • Change the name to remove unsupported characters
  • Save by pressing CTRL + O
  • End by pressing CTRL + X
  • Start the hostname script with this command service hostname start
In Centos-based Systems
  • As root or using sudo, edit the /etc/sysconfig/network file with the following command: nano /etc/sysconfig/network
    • If nano is not installed, either use another text editor such as vi or install nano with the following command: yum install nano
  • Change the hostname to remove unsupported characters
  • Save by pressing CTRL + O
  • End by pressing CTRL + X
  • The change will take effect after a reboot.


Network Guidelines for USB-over-LAN Multiseat

Userful recommends the following network hardware (exact details will depend on the number of stations to be set up and the desired physical configuration).

  1. Good quality network cable for all connections is important. Cable should be Cat-5e.
  2. Ethernet zero-client devices should not be connected to the computer directly, but should connect to a network switch.
  3. More than one switch can be used - and in fact may be desired, depending on the physical configuration of the room or rooms.
  4. A good quality router is needed to act as a DHCP server to give IP addresses to the USB-over-LAN devices, unless using a static IP address for each device.


Network Speed/Capacity

LAN-connection-speed.png

Different parts of an Ethernet Zero-Client MultiSeat LAN have different connection speed minimum requirements. When planning your deployment, please ensure that routers and switches have the required number of gigabit ports, as described below:

  • The required speed of the connection from the router (which is required to provide a DHCP server, and provides a connection to the outside network or internet) to the main switch depends on the speed of the uplink to the internet/outside network.
  • The connection between the host PC and the main switch MUST be gigabit capacity.
  • The connection between two switches must be gigabit capacity.
  • The connection to a single network device can be 10/100 Mbps.


Other Network Considerations

  • Depending on the size and complexity of the installation, you may want to isolate the network station LAN from the existing network infrastructure using a router or a VLAN.
  • Do not place a router between the host PC and any Ethernet devices. The router may introduce small delays that can cause system instability.
  • It is important that the host PC is on the same subnet as the network devices.
  • If there is more than one host PC on a subnet, they must have unique hostnames. This is because ethernet zero-client devices are locked to PCs based on the system name (or "hostname"). Having duplicate host names on one subnet causes erratic behaviour of the network devices.
  • If connecting to the internet through an ADSL modem with a static IP address, a router is still needed (to act as a DHCP server). Two options for connecting through an ASDL modem:
    • Recommended: Connect the modem to the WAN port of the router. Connect a switch to the router; then connect the host PC and stations to the switch.
    • Advanced: Connect the modem, router, host and stations to a managed switch in a star topology. Configure the routing tables in the switch to recognise the modem as the gateway and the router as the DHCP server.
  • Userful recommends deploying no more than 30 stations on a given subnet.

Example Configurations

1 Onboard + 20 Network Stations Using Single 24-port Switch

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1 Onboard + 18 Network Stations Using Three 8-port Switches in Series (Daisy-Chained)

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1 Onboard + 18 Network Stations Using Three 8-port Switches in Parallel (Hub-and-Spokes)

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If the standard configurations shown in the examples above are not suitable for your deployment, please contact Userful or consult with an expert in networking and network deployments when planning the configuration of your system.

In addition, Userful recommends testing your desired network configuration with expected use cases before deployment.