Network Basics for Userful

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Copyright © 2018 Userful Corporation. All rights reserved.
(Updated 2018.10.19)

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Introduction

Userful Video Wall is different from almost any other Video Wall and Digital Signage platform on the market, in terms of how content is delivered to the displays. The closest conventional term that can be applied to our Server/Receiver model is Video over IP. However Video over IP is typically used to describe network streaming protocols, one-way traffic that can handle a certain amount of disruption and slowdown. This is not the case with Userful.

A Userful receiver operates with two distinct components. One is the device itself, the other is a software driver in the server. The two combine to take video, USB, and audio data, translate it into network packets, and send it out via the network. The receiver's chip decodes and utilizes the data. The server receives traffic, decodes the information, and sends the various video, USB, and audio signals to their respective parts of the system.

As far as the operating system is concerned, each receiver is a USB device with a display adapter on it. This creates some important operating conditions for Userful receivers.

A properly configured network that follows all below conditions is *absolutely essential* to the successful operation of Userful, in any use case

Networking Basics

Networking knowledge can be uncommon in the A/V industry. This guide is intended to deliver a primer on the basics of what you need to know to deploy Userful. If you or a member of your technical staff have CompTIA Network+ certification or equivalent experience, this guide can be skipped.

  • It is highly recommended that a member of your staff or a contracted professional have CompTIA Network+ certification, or equivalent knowledge and experience, when installing Userful systems.*

In the interests of keeping this guide readable, some terms are oversimplified. This guide should not be considered a definitive resource for networking, or a replacement for CompTIA Network+ certification.


Hardware

Network hardware, for the purposes of Userful, consists of a few elements.

Network Interfaces

A basic network card that can be installed in any PC
A basic network interface built into a PC
A basic network switch with multiple ports

Network Interfaces are the ports in the back of just about every computer, server and switch made. They have many traits, but the important part we are going to focus on is connection speed.

Interfaces can transmit and receive data at several speeds, normally measured in megabits per second (Mbps). This speed is almost always denoted as a multiple of 10, and interfaces capable of higher speeds become more affordable and common over time.

Most interfaces in computers these days are rated at “10/100/1000” speed, meaning they can operate at fixed rates of 10, 100, or 1,000 Mbps. This is often referred to as “Gigabit”, or 1 Gbps. Increasingly common are 10Gbps connections, which offer 10 times the bandwidth.

The rate an interface picks is dependent on two factors:

  1. The maximum speed of the interface on either end of the cable
  2. The rating of the cable.

The maximum speed of the interface is automatically set using Autonegotiation to the best possible speed available to all parts.

Userful-certified and supplied systems come with two network interfaces for best stability. One is intended to connect to your existing network and the Internet. The other (either a 1Gbps or 10Gbps) is to be used to talk to the receivers. This is the recommended configuration for all production Userful systems.


Network Cables

A basic Ethernet cable

Network Cables, typically referred to as Ethernet cables, are the links between network interfaces. They are most commonly blue in color, though other colors are frequently used, and do not definitively denote different types or capabilities of cable. Their connector end looks like a large telephone plug and clicks in exactly like one.

Again, there are many traits to Ethernet cabling. The primary one we will focus on is its rating. All network cables are rated to a certain standard of Ethernet capability, using categories.

There are extensive Wikipedia articles that go into exact detail on Ethernet ratings and such, again we will focus on the two necessary specifications. Both are readily available and inexpensive.

1: To connect a conventional Zero Client Receiver to Userful, you must use Category-5e often abbreviated as “Cat 5e”) cabling or better. This is also the minimum required cabling for Power over Ethernet (PoE) devices.

2: To connect Ethernet 10Gbps links, Category-6a (Cat-6a) cabling or better is required. More frequently available are SFP or fiber-optic ports. These are complex and beyond the scope of this guide.

A network cable can be run in individual lengths of up to 100 meters/330 feet between interfaces. The interface can be a network switch or repeater, though using more than one of these between the Userful host and a Receiver is not recommended.


Network Switch

A larger network switch capable of connecting multiple devices. This particular model has 48 ports and 4 uplink ports to the left - two Ethernet (bottom) and two SFP fiber-optic connections (top). This switch is also capable of distributing Power over Ethernet (PoE) denoted by the segments outlined in red.

A switch is a device with many network interfaces that intelligently routes traffic coming from one interface to the device it needs to go to. Think of it as a rail yard junction. In a way, they function almost as the “distribution center” for Userful’s receivers. The network interface in the Userful server connects to one port on a switch. The rest connect to Receivers, and the switch directs traffic.

It’s important to note that switches are just one type of several kinds of device that are common in networks. For our purposes, it is important that the device being used is a switch, and not a router, gateway, hub, or firewall.

There are several kinds of switch. They range in price, availability, and complexity from $30 off the shelf at Best Buy to well over $10,000 through agreements with major organizations. Generally they have between 4 and 52 interfaces. How many you need depends on the size of video wall you are creating, in terms of the number of displays it must connect. Keep in mind that you should always add 2 to this number, one port to connect to the Userful server, and another to connect another PC or to your network, if necessary.

It’s not necessary to spend $10,000 on a switch, nor is it recommended to spend only $30. There are many options available from reputable names such as HP, Linksys, Netgear and Cisco, among others, that retail for under $200 USD for a model with up to 24 ports. You can certainly use more expensive models as well if you require features such as Power over Ethernet (PoE, the ability to deliver a limited electrical current over the network to a device) or the ability to remotely manage and control this switch (a trained professional is necessary for this, Userful does not support network equipment).

Any switch, Userful server, and set of zero clients will form a very basic Local Area Network, or LAN. These more complicated switches are also capable of being set up so that different ports perform different functions or to be only aware of a few of their neighbors. This can be called a Virtual Local Area Network, or VLAN. If you need to set up one of these for Userful, see your staff network technician. If you don’t have this resource available, it’s best to just use one entire switch for Userful.

Every interface on a switch must be capable of at least 1000Mbps/1Gbps to function properly, if this switch is to control up to 12 individual displays, or 24 video wall displays. If you need to control more, a switch with 10Gbps uplink ports is necessary to handle the traffic going to and from the server.


Software and Protocols

We’ve been over the hardware elements involved in setting up Userful. Now we need to dive into what’s going on inside all those wires and switches, so we understand why and how everything gets set up the way it does!

IP Addresses

A very basic network with IP addresses.
Setting a static IP address with Userful Control Center.

Every device on the end-point a network (servers, computers, phones, zero client receivers) needs to have an IP Address. This address is used to communicate with the device in much the same way every phone, fax machine, and automated voice routing service has a phone number.

When you sign up for a phone line, you’re given a single phone number. This is important, because if your phone number changes every few days or weeks, your job is much more difficult, if not impossible, to do.

Your phone number is also unique. Maybe your entire company shares one phone number, but you have a unique extension at your desk. This is also important as if you shared a phone number or extension with one or more others, your job suddenly becomes very much more difficult, or impossible if you both rely on your phones all day!


IP Addresses work in the same way. Computers are very good at keeping track of changing addresses, so setting a permanent, or Static IP Address is not critical in most cases. If an address changes, all the other devices it needs to talk to have their “address books” updated instantly.

Userful receivers each need to be given an IP address. When a receiver is fresh out of the box, it looks for a service to assign it one of these addresses. This is called DHCP, short for Dynamic Host Configuration Protocol. If your network has this, it will give the receiver an address. If it does not, the receiver will give itself an address after trying for about 30 seconds or so. But the address it gives itself will be invalid for your network, so Userful won’t be able to talk to it properly.

The Userful server can be set up to act as a DHCP server quite easily. This gives each receiver its address they can use to communicate to the server.

However, these addresses like to change. Typically an IP address is “leased” from the server in this manner. When this lease expires it must be renewed. Most of the time, the same address will be given to the device, but sometimes a new address is given. If this happens to a Userful receiver, the connection will temporarily drop while it assigns itself the new address, and then reconnects to the server. This process typically takes up to 10-15 seconds to complete, which is not very nice in any use case!

To prevent this, we should give each receiver a Static IP address, one that does not change until someone tells it to. This will improve the overall long-term stability of a Userful system and is strongly recommended.


Common Problem Points

Userful receivers are very sensitive to network conditions. If connections do not meet specifications, performance issues and system crashes absolutely will occur. There are two very common terms to be familiar with when planning and deploying a Userful system.

Saturation

A common problem is saturation, which can occur if there is too much traffic passing through a switch or single interface. This causes “traffic jams” in the system, and traffic starts becoming lost and dropped, also causing packet loss. It’s important to ensure that a 1Gbps interface is not talking to more than 20 individual receivers at once, if you need to do more, a 10Gbps set of equipment (interface, cable, and switch) is required.

There still exists, especially in older buildings, a good deal of network switches and cabling that was designed for 100Mbps operation, one-tenth the minimum speed required by Userful. Userful will report to you if one or more of its devices is connected to a 100Mbps connection. Extreme instability and system crashes will occur if Userful is forced to use 100Mbps connections.

Latency

Latency describes the amount of time it takes for information to travel from one point to another. Low latency means good responsiveness. Bad latency means accessing information or services takes longer, and if it’s bad enough, the initial request may expire and fail.

Traditional computer systems can handle a great deal of latency. If a website or printer takes several seconds to respond, it’s not a problem, though annoying. Most of the time, latency is measured in milliseconds, where 500 milliseconds is half a second, and considered decent latency for a large office or university campus. Devices in the same building on a large network may come closer to 10 or 20 milliseconds, at most.

Userful receivers have much lower tolerance for latency and must be able to rely on dependable latency between themselves and their server of 0.5 milliseconds or less. That is one-half of one millisecond, to be perfectly clear.

This is easily attainable with even a basic $200 switch acting as a “hub” for a Userful server and all its receivers, and the above specified cabling is enough to ensure this specification. Where things start getting unstable is if additional equipment or repeaters are used, or if a switch is replaced with a more complex device like a firewall or router.

Packet Loss

The second important point is the quality of the connection, losses in which will result in a condition called packet loss, where some of the information gets “lost” on its way to the receiver or server.

This most commonly happens if a network is saturated with traffic, or if some physical element of the network is damaged or broken - a loose connector, damaged cable through cutting or kinking, or failing switches or interfaces.

Many computer systems are tolerant to packet loss. If information is not received, or recieved incompletely, the device at one end simply requests it again. However a Userful receiver operates exclusively in real time, so corruption in its datastream will have similar consequences to poor latency - you will see playback degradation, stuttering and sync problems, and frequent system crashes.


Local Area Network (LAN)

An example of a simple LAN.

A Local Area Network or LAN describes the collection of cabling, switches, servers and computers in your office that make up your network. The definition of “Local” normally applies so long as the network is all contained within the same physical premises - a single office or office building or campus under the control of a single organization.

Userful can work on your LAN, but just connecting everything through a random port available in the wall is not recommended. Userful receivers generate a very large amount of network traffic each, and they can quickly overwhelm the computers, printers and other devices attached to that same LAN. At the same time, those devices are generating their own traffic, adding to the storm, which will cause Userful to malfunction as well. In worst-case scenarios, if Userful and its receivers have to share ranges of IP addresses with wireless devices, you have a recipe for complete disaster.


Steps for a Successful Userful Deployment

An example of a recommended Userful network setup.

There are a number of best-practices to follow to ensure your Userful system remains stable and working well past the installation date.

First, and most important, Userful receivers should follow the pictured layout for optimal performance.

This places Userful on your network, accessible to users and administrators, and also able to do things like receive network streams and Web content, and also connect to the Internet so the system can receive software updates and easy support from Userful.

This also creates a protected, isolated environment for the recievers to operate in, independently of the rest of your network. Userful receivers do not communicate with anything other than a Userful server, so there is no need to be able to directly connect to them from outside Userful.

This will effectively isolate Userful from intrusion attempts while still allowing it to connect to the internet to receive updates and support.


Network Requirements

The following is a list of minimum requirements for Userful in order to function correctly, in any use case.

  • Having two network interfaces installed in the Userful server is strongly recommended.
    • To address up to 12 independent displays, or 24 displays in a video wall, an independent 1Gbps connection between the server and each receiver is a requirement.
    • To communicate with more than 12/24 displays, a 10Gbps connection to a switch is a requirement.
  • Due to the high volume of traffic potentially interfering with other systems, a separate, completely segregated network or LAN is strongly recommended.
  • Latency between the Userful server and receiver cannot exceed 0.5ms - this is one-half of one millisecond, not 5 or 50 or 500 milliseconds.
  • Packet loss between the server and receiver cannot exceed 0.01%.


Next Steps

If you've finished this page and have a good understanding of its content, you can now move on to the Setup Guide, or see the Hardware Setup Guide that was included in your Userful shipment to configure your hardware.

External Links and Resources