When in AV (Audio Visual) we are often met by three-letter acronyms. And sometimes it’s just numbers. In this article it’s the numbers 8, 0 and 2. We are met by them together with other numbers and letters almost daily, some examples are 802.11, 802.3, 802.1. Then let’s add some letters to… 802.1q, 802.3bt, 802.11n or even more numbers. 802.15.4. But what do they all have in common? And what sets them apart?
In this article I will start exploring these abbreviations and go through some of them. What they do and when to use them. Some of them will even merit their own article because of the amount of relevant information that exists about these designations.
Disclaimer
I don’t claim this is a complete guide to all necessary standards within the 802 group in any way, but it is some of the standards I am asked about or that are contained in courses I teach. Therefore, I felt it is a good starting point for explaining some of them for people working in AV.
Some of the below standards are also not explained as thoroughly as needed, but I hope to be able to draft some separate articles about them in the future where I can focus more on some of the relevant details for the AV professional.
IEEE 802
IEEE is the abbreviation for “Institute of Electrical and Electronics Engineers” (https://www.ieee.org/), a global organization working with, among other things, standardization of networking. IEEE 802 only works within the lowest two layers of the OSI model, the Physical and DataLink layers. Layers three to seven are being handled in other standards.
In February of 1980, a new Standards Committee had its first meeting. The “IEEE 802 LAN/MAN Standards Committee” and since the next available number for standards was 802, that became the assigned number. There is no connection between 1980 and month 2 in the naming even though it is an interesting coincidence and sometimes heard as the reason for that particular number.
In this article I will start to go through some of the so far 24 different groups within the 802 committee, these are 802.1, 802.3, 802.11 and 802.15 and some but definitely not all sub standards within these committees. The focus will be on the ones applicable in AV.
IEEE 802.1 – Higher Layer LAN Protocols
The 802.1 Working Group within the IEEE 802 Standard Committee work with maintenance, security, and time sensitive networking. Their web page can be found here: https://1.ieee802.org/
IEEE 802.1q
The IEEE 802.1q standard is more commonly referred to as VLAN (Virtual Local Area Network). This is a way to use a physical infrastructure to logically separate the infrastructure into smaller more manageable or for other reasons segmented parts.
The reasons to do this can be many. For example, to separate a vast network with thousands of devices into smaller parts to minimize overhead traffic like broadcast. Or it can be to create different networks for guests, office computers, servers for internal or external use or any other number of ways to make the network more easily defined.
When we separate the network into VLANs, what we do is we add a number (a tag) to the ethernet frame representing a particular network within our own environment. Valid numbers are 1 to 4094 and are stripped away again when the traffic leaves our network. That means the tagging isn’t valid outside of our own network and we can segment the network with any of the defined numbers we want.
Usually the first number, 1, is used as a default network but the use of the default network is always up to the network architect or administrator.
An ordinary port to a common endpoint like a computer or a DSP is usually configured as an access port in the switch. The access port gets a VLAN number assigned to it, but the connected computer or DSP isn’t aware of this. The purpose is only to route the traffic on that port through the correct logical part of the network within the physical hardware. So, as soon as the access port needs to send the data on through a trunk port, a port that simultaneously can hold multiple VLANs in the same cable, the VLAN tag is added.
So, the other most common type of VLAN port is the trunk port. The trunk port can have more then one VLAN tag assigned to it and thereby send traffic from different VLANs between, for example network switches or to a WLAN access point handling multiple different networks.
A trunk port can also have a value set for “untagged” traffic. That is, if the packet sent on the port does not have a VLAN tag defined, this is where it will end up. For example, a server can have VLAN 2, 5 and 127 defined and if traffic is sent with any of those numbers in the VLAN tag field, the traffic will be routed to the corresponding networks. However, if the server sends an untagged packet, it will then be assigned the default value for untagged traffic on that port.
Different ports in the switch can be set differently.
There are ways to handle more than 4094 VLANs but we don’t encounter them in the AV world. These larger networks used in for example MANs (Metropolitan Area Networks, city-wide networks that can connect for example all houses in a city to a common fiber infrastructure) can use a method called QinQ defined in IEEE 802.1ad. Simply explained, we but 4094 VLAN tags in each of the standard 4094 VLANs we already had defined)
IEEE 802.1x
This is the standard concerned with network security and is sometimes called dot1x pronounced dot-one-x. It is the standard defining a way to “authorize” particular devices on the network in the switch before they are allowed to communicate with anything else. This can be really useful in a network for several reasons. One is of course for security purposes. That is, when a device is connected, it can negotiate about access and if it is allowed to get access to the network based on for example a certificate, it is let in to a specific network decided by a server handling the negotiation. If it isn’t in the system as an approved device, it can either be sent out on a guest network with internet access only or the port can be shut down automatically since no device should be connected to that particular port in that switch. This can also in some type of installations trigger an alarm or since it can be seen as an intrusion attempt.
Another way to use 802.1x is to have all ports work with this negotiation, making it really easy to let anyone connect to almost any port and through the negotiation tell the switch port to become the corporate office network for their internal laptops, an AV VLAN for a pre-configured DSP or a guest VLAN port for an unknown device. This means an employee can connect anywhere and don’t have to think about if this is a network where he or she will be able to reach the ERP or the company servers. In the same way, an AV professional can connect a listed device in the closest network port and get the AV VLAN. If someone else unplugs that device and connects their own device, the VLAN can change.
Often, in these networks, network administrators also decide only one device at a time is allowed to connect and if two devices connect at the same time, the port is disabled. Why? Because what network should they open up? If we put a simpler switch into the corporate switch and then first connect an approved device, and then in the next port we connect something malicious, how can we then stop the malicious device from gaining network access in a sensitive network?
802.1x can also be used in wireless networks, making it easy to authenticate users and computers without have to share a common key for the network. We can use either username and password, for example the same as we use for the computers and our e-mail and VPN access. Or we can authenticate using a certificate loaded onto all corporate computers. That certificate and the negotiation with the servers in the network can then decide on which network this device should end up. For example, in the office computer VLAN or in a specific network for warehouse computers or anything else.
The world’s largest network like this is probably the university network called eduroam. In this network any person associated with their “home university” can go to any other university (or other institution connected) in the world connected to the network of networks and gain guest access to the internet. This works by username and password where the student or professor uses their credentials from their home university and log in. The system will then ask the home university if they trust this person and if they do, they are let in to the network.
IEEE 802.3 – Ethernet
So, the 802.3 standard concerns itself with wired ethernet. That is, when you use a network cable with an RJ45 connector. The most common place to find relevant references to the 802.3 standard in AV is when we talk about PoE.
PoE is short for Power over Ethernet and it’s a set of standards that can be quite tricky to understand what you actually need and what will happen if negotiation fails. I won’t delve into this in this article but will give a short overview of the different standards we may encounter. There are three common ones.
IEEE 802.3af
This is the first PoE standard. It gives us 15.4W per port from the switch. That’s not what the powered device actually needs but it’s what the switch needs to be able to output on a port. But as we all know, when we transport power in a cable, we have some losses turning into heat and in a worst-case scenario we only have 12.95W left to power the actual device after transporting in cables up to 100 meters.
In the IEEE 802.3 standard this is also called Type 1 PoE.
Within the Type 1 PoE standard there are also classes defined (they aren’t only implemented in Type 1 though) so a Type 1 PoE device can request power from the switch to power a device needing up to for example 4W (Class 1), 7W (Class 2) or 15.4W (Class 3). There is also a Class 0 used if the power negotiation fails or if no class is requested. The switch will then simply output 15.4W.
IEEE 802.3at
The next PoE type that is defined is the Type 2, also named 802.3at or more commonly and simply – PoE+.
For PoE+, the switch will output up to 30.0W and the device will be able to be powered by up to 25.50W. The class is Class 4 and it can use LLDP (Link Local Discovery Protocol) to make requests for the amount of power needed. Thereby, not needing lots of classes pre-defined
IEEE 802.3bt
The third and (currently) last PoE standard is the IEEE 802.3bt, also called PoE++ (or 4PPoE for 4 Pair PoE, that is, all pairs in an ethernet cable). However, it’s divided into two. We have the Type 3, defined for up to 60W from the switch and 51W for the device being powered. But there is also the Type 4 that can deliver 90W from the switch to 71.3W to the powered device. However, as of today, very few devices actually need this. But it’s there.
Sometimes we see something called UPoE too. But that is not a defined standard but a proprietary way to deliver up to 60W of power that Cisco came up with before the standards had been set. Sometimes however, some people use the terms PoE++ and UPoE as the same thing.
IEEE 802.3az
IEEE 802.3az, or commonly EEE, Energy Efficient Ethernet is something we in AV have been taught to disable since it does more harm than good with its power savings. Sometimes it’s also called Green Ethernet. Unfortunately, we often rely on the PTP clock in AVoIP in AV installations and since the purpose of EEE is to send larger bursts of the small packets, but we really need the small packets to arrive in order and with equal distance in time, EEE is not something we encourage. They can sometimes also lower the power output from PoE, which is not something we usually want.
There are several official statements from manufacturers stating this to, like Audinate about Dante here: https://www.getdante.com/support/faq/can-i-use-eee-energy-efficient-ethernet-or-green-ethernet-in-my-dante-network/
And Crestron: https://community.crestron.com/s/article/id-5764
IEEE 802.11 – WLAN
IEEE 802.11. Probably the standard that everyone can relate to today. Wireless networking. So, let’s do a quick tour through the alphabet without going too deep here. This article is not meant to explain Wi-Fi, it is after all meant to describe different 802 standards used in AV.
The first standard didn’t have a letter so let’s call it 0 (zero). Then came 802.11b (11Mbit/s). Then came…
802.11a
802.11g
802.11n
802.11ac
802.11ax
802.11be
802.11bn
So as anyone can see, this fast became a mess, but it wasn’t until 802.11ax we actually got a more structured name for these standards, the marketing suddenly said Wi-Fi 6 instead of 802.11ax. That meant 802.11be became Wi-Fi 7 and the next standard will we 802.11bn, Wi-Fi 8.
So, the key will be
Wi-Fi 1 – 802.11b
Wi-Fi 2 – 802.11a
Wi-Fi 3 – 802.11g
Wi-Fi 4 – 802.11n
Wi-Fi 5 – 802.11ac
Wi-Fi 6 – 802.11ax
Wi-Fi 7 – 802.11be
Wi-Fi 8 – 802.11bn
With every new iteration, the speed increased from 11Mbit/s around the year 2000 to today’s Wi-Fi 7 and 30Gbit/s. Of course, this is nothing we have seen yet but it’s there, in the standard: https://standards.ieee.org/ieee/802.11be/7516/
Besides higher total throughput we also get new features and more efficient transmissions utilizing different techniques to optimize transmission and minimize for example the need for re-transmissions while using higher frequencies allowing more data per time unit simply (it’s not simple though) through the number of waves per second (frequency).
IEEE 802.15 – Wireless Specialty Networks (WSN)
I wasn’t sure to actually include this one here but after a lot of thought decided to add this chapter about 802.15 and briefly mention parts of it that are being utilized in AV.
IEEE 802.15.1 – WPAN / Bluetooth
WPAN or Wireless Personal Area Network. A small network we carry around in our pockets through our mobile phones and the accessories we use. Bluetooth has been around for a while now and the usage has increased and finally after a couple of years found its way into the conference room. Not always that successful I might add, but it is there.
We have had our small speaker/microphone pods for a couple of decades now, but they are more portable devices and the usage in the conference room was more that someone put it there more or less permanently. But since we have gotten more permanently installed devices from different manufacturers.
For example, the AVIO adapter with Dante from Audinate. Nice product, but when used in a conference room, there is a flaw. You have to press the button on the side to pair it with your device instead of just giving us an API command to trigger for pairing, that way making it possible to hide it in the ceiling or in a (non-metal) cabinet.
And others have released their products that help us get Bluetooth into our conference rooms for connecting our phone-calls, play music or just as a beacon to signal presence of a particular handheld device or to discover an Apple TV unit.
These devices and many more make it possible for us to connect, discover and extend the uses of our conference rooms. Maybe not something needed in all rooms but in the right one or just to be able to stream some music in a home or the kitchen at a company.
IEEE 802.15.4 – Low-Rate wireless PAN
Probably the least known 802 standard in this article. IEEE 802.15.4. It’s here because it’s a standard that many companies built their platform on. Like IKEA Trådfri, Philips Hue and Crestron InfiNET.
This is a clever little protocol for devices that are short range but that through mesh networking can be extended quite far. Usually, they are proprietary implementations of the protocols used but, in some cases, they can talk between manufacturers’ devices.
For every non battery powered device, we usually extend the range of the network while the devices operating on battery power try to conserve battery by sending out as little as possible as seldom as possible. Sometime this can extend the battery life to months or even years depending on the product.
It is working in the 2.4GHz band just like some Wi-Fi networks and lots of other devices since it’s free to use. However, we can often choose frequency bands above the Wi-Fi networks. For example, here in Sweden, we usually use band 11 as the highest frequency band in Wi-Fi but can use band 15 with ZigBee.
What about PTP?
There is another standard that is crucial for modern AV networks, The PTP (Precision Time Protocol) standard. But PTP is not part work by the 802 committee (since it is an OSI layer 7 protocol) and therefore not covered in this article.
PTP is covered in IEEE 1588-2002 for PTPv1 and IEEE 1588-2008 for PTPv2. There is also a PTPv2.1, IEEE 1588-2019.
For more information about the IEEE 1588 standard, see https://www.nist.gov/el/intelligent-systems-division-73500/ieee-1588