Written by Terry Doner. November 23, 2020

THIS ARTICLE IS IN DRAFT

Introduction

Things are changing in the work of church production technology. Almost everything has a computer in it these days. And almost everything can be network connected. This demands a whole new skill set of the tech team; often already stretched.

The additional of well designed network infrastructure to your operations can help a lot. A poorly design one can be a major source of frustration and problems.

What are some examples of useful examples of network technology?

1. Being able to sit anywhere in your auditorium and adjust your audio mix on an iPad

2. Running sound check from the stage without having to keep running back to the booth

3. Running your video feed from the video mixer to the nursery without having to run dedicated cables the entire way

4. Running your lighting DMX controls over the network

5. Stream your service to the internet

Network Basics

A computer network is a mechanism for two or more computers to communicate with each other. These days there is one common core of technologies that are useful in church production environments that we will focus on.

[Follow the description in the diagram below, and more details of each in the sections below.]

To start with everybody want access to the internet for email, web browsing, etc. This is a service providing by an ISP (Internet Service Provider). They need to create a connection to your facility. This uses one of several connection types: cable, DSL, fiber, microwave, cellular and satellite.

The ISP will need at least one device at your facility, usually a modem. The modem acts as a translator between the communication protocols used by the ISP and the computers in your facility.

A router manages the flow of communication between two networks. An 'internet' is a collection of networks. So we can consider all of the 'internet' to be one network, and your church being (at least) another network.

Think of a switch as a device similar to a train track switch (not a light switch), the flow of information across your network is like a train and the various wires are like the tracks. So the switch manages the path the our information takes between devices.

Our computers and other devices is the end of the line for the story, but some devices, like laptops and tablets might see one more step, and that is a wifi network. This is enabled by a wireless access point, or WAP.

The boxes in the diagram might not match the boxes on your shelf. It is common that several functions are combined in a single package, especially in home networks. Your ISP may give (or rent) you a box that combines the functions of a modem, router, switch and WAP in a single box.

A Sample Design

ISP

ISP, or Internet Service Provider, provides the connection to your facility. This uses one of several connection types: cable, DSL, fiber, microwave, cellular and satellite.

These connection types have varying performance characteristics. The key numbers are

• Upload bandwidth

• Download bandwidth, and

• Ping time

The bandwidth metrics are normally in Mbps (Mega bits per second), the ping time is typically in milliseconds. A metric in MBps is Mega Bytes per second. 1 MBps = 8 Mbps.

Modem

The ISP's connection at your facility will usually end at a modem. The modem acts as a translator between the communication protocols used by the ISP and the computers in your facility.

Router

A router manages the flow of communication between two networks. An 'internet' is a collection of networks. So we can consider all of the 'internet' to be one network, and your church being (at least) another network.

Firewall

... <To be written>

Switch

Think of a switch as a device similar to a train track switch (not a light switch), the flow of information across your network is like a train and the various wires are like the tracks. So the switch manages the path the our information takes between devices.

If you plan on:

• having more than a handful of devices on your network,

• or you plan on making your network available to the public,

• or you plan on deploying NDI or audio over internet (eg Dante),

you should be using managed switches.

Wireless Access Point

Our computers and other devices is the end of the line for the story, but some devices, like laptops and tablets might see one more step, and that is a wifi network. This is enabled by a wireless access point, or WAP.

Addressing

Internet devices typically have three identifies or "names".

The first of these names is called a MAC address (Media Access Control) and has nothing to do with Apple computers! It is an address that is set by the device manufacturer and the look like 00:0a:95:9d:68:16 . The ones set by the manufacturer are called "Universally Administered Addresses", but it is possible to set your own and these are called "Locally Administered Addresses". You won't typically need to worry about the Locally Administered ones. If a computer has two different interfaces, say a wired ethernet port and a wireless port, they will each have their own MAC address.

The second type of name is the IP address; they typically look like this 192.168.1.85 or 10.0.0.43 these are determined by your network configuration. This happens in one of three ways:

1. Statically assgined addresses: these are directly assigned in the configruation interface of each device.

2. Dyanmically assigned addresses: these are assgined by a dhcp server according to rules determined by your administrator (which could be default). Dynamic addresses can change value over time.

3. Reserved addresses: reserved addresses a blend of the first two. They are managed by the dhcp server via a mapping table. This table has the IP address to be used for each MAC address.

Sometimes you need to know the the address of a machine into order to establish a connection between two of them. If this is needed then the reserved address is a reasonable approach in a fixed installation (not mobile). Static addresses become difficult to manage in larger neworks.

One very important rule about IP addresses is that they must be unique within your network.

The third type of name looks more like a name than the other two which were numbers. You will be very familiar with them, examples like www.google.com or www.youtube.com. There is another kind of server called a dns server - this manages the realtionship between these names and the IP addresses.

If you use a dns name, like in a web browser, the first thing it must do is ask the dns server for the IP address which corresponds to that name. This IP address is used to place on the "envelope" of the data messages that will be sent. The IP address is used by the routers and switches to get the messages to the correct switch and then finally the last switch will need to translate the IP address to the MAC address to deliver the message to the correct device.

Network Design Principles

1. Setup your networks so that the general public does not have access to the internal devices

2. Use dhcp reserved addressing instead of static addresses, unless you can't or have a good reason to not. If you choose to use static address, you need to maintain a list of each device, its MAC address and assigned IP address.

3. When running cable, keep it neat and tidy. Don't take the shortest path if it will cut across a pathway (for example in the attic).

4. For your main runs, consider running a spare cable as a backup. If there is every a problem with the main run, or you suspect a problem, you can easily swap to a backup.

5. For PoE (Power over Ethernet) solutions, know your power draw per port (and what each port can supply), as well as the total power your switch can deliver.

6. Label your cables at each end.

7. Be neat, every time, otherwise you will end up with a nightmare rats nest. Which of these would you rather have?

Security Practises

1. Keep a registry of all your passwords in a secure place. A second person should be able to access this registry as well.

2. User accounts should only be given the least privilege as needed for normal operations

3. Assign passwords to all devices and disable default accounts after creating and testing your own. I create three accounts on most devices: a primary admin account, a backup admin account and as many used accounts as are needed.

4. My church has a person who runs the IT infrastructure and we work together on all of this. He has his own admin account that he has for access.

Other Topics For Future Reversions ;)

Subnets

Core and access layer

VLANs

segregation

wifi

For Further Reference

• https://www.thebroadcastbridge.com/content/entry/888/the-anatomy-of-the-ip-network-part-1

• https://www.thebroadcastbridge.com/content/entry/894/the-anatomy-of-the-ip-network-part-2

• https://www.thebroadcastbridge.com/content/entry/895/the-anatomy-of-the-ip-network-part-3

• An Introduction To Audio Networking

• This is a comprehensive and up-to-date book which goes into much deeper detail. "Introduction to Show Networking", by John Huntington, https://play.google.com/store/books/details?id=f2YLEAAAQBAJ

Bobblehead Fred on networks, specifically for lighting

Audinate has published a series of videos about Dante and networks, this is the first one.