Network Definitions

10/100/1000BASE-T

Common data-rate transmission speeds expressed as megabits per second (Mbps or Mb/s) used in Ethernet-based networks. 100 Mbps has been the most common for a number of years, although 1000 Mbps is becoming much more common, and is also frequently expressed as 1 Gbps (Gigabit per second). 1 Mbps is equal to ~125 kilobytes per second (KB/s) bandwidth, so while approximately 125 megabytes per second (MB/s) is theoretically possible on a 1000 Mbps connection, observed bandwidth on any connection may be slightly less due to processing overhead and other capabilities of the networking hardware.

2.5/5/10GBASE-T

Common data-rate transmission speeds expressed as gigabit per second (Gbps or Gb/s) used in Ethernet-based networks. Currently they're not as common in the consumer market

2.4GHz

The frequency band in the radio spectrum used by many Wi-Fi devices. Shared with Bluetooth, Zigbee, and many other wireless technologies. Has a potentially longer range than 5GHz Wi-Fi and greater compatibility with older devices, but has lower potential bandwidth.

5.0GHz

A newer frequency band used by Wi-Fi devices. Has a higher bandwidth than 2.4GHz and is less likely to interfere with other common wireless technologies, but has a potentially shorter range. Many modern routers and access points can broadcast both 2.4GHz and 5.0GHz Wi-Fi using two different SSIDs, and internally bridge the two networks.

Access Control Entry

See Access Control List. An Access Control Entry (ACE) is an individual line or condition in an ACL. For example, an ACE condition may block port 5568, which is used by sACN lighting-level packets. That would be one line/condition in the ACL and is considered an ACE.

Access Control List

An Access Control List (ACL) is a feature in network switch hardware. This feature allows the switch to block or allow network traffic based on specific conditions. The conditions are input by a technician using the network switch's Console Port or web user interface. This ACL is applied on a port-by-port basis (physical network ports on the hardware). Think of an ACL as a traffic monitor that inspects every network packet entering or exiting a network port. The packet(s) will either be blocked or permitted based on the conditions in the ACL. Depending on the capabilities of the network switch, the ACL may be applied to incoming traffic, outgoing traffic, or both. The most common ACL used in ETC networks is to block sACN lighting levels. 

In this example, two different areas of a building each have a lighting controller that both use sACN universe 1. Both areas of the building exist on the same lighting network but are on different lighting switches. It is then desirable to block sACN traffic between the network switches so that area A doesn't accidentally control area B.

For more information on how to configure ACLs in Cisco network switches, see this article.

Anycast

Used to describe the transmission of data over a network. Read the Multicast definition first to better understand the concept of Anycast. First, there are no ETC products that support Anycast at this time. Anycast is when a network device (receiver for multicast network traffic) sources its multicast network traffic from the closest logical source on the network when multiple sources are present. A good analogy would be to think of Internet video streaming services. If the streaming service has let's say 5 locations around the country that all host a video that you want to watch, Anycast would tell the network switches (network infrastructure) that your receiver (home PC or smart TV or phone) would stream the video from the closest logical host (source). The video would be streamed over multicast (only those who ask to get that information will get it). Once again, this is not supported by ETC hardware. In a lighting network, if more than one source of sACN exists, the receivers, DMX gateways for example, would want to receive all sACN sources and decide for itself which one "wins" using HTP (Highest Takes Precedence) and sACN Priority values. Hence, lighting receivers want to listen to all multicast sources.

arp -a

This is a Command Prompt command. The purpose of arp -a is to return or print a list of IP Addresses and MAC Addresses that this computer has communicated with. This is an excellent way to gather a list of MAC Addresses for the ETC networked hardware on a site. The easiest way for your computer to interact with networked hardware is to run Concert or other product specific software such as LightDesigner or EchoAccess. The simplest way is to simply ping an IP Address and arp -a will return the MAC Address. In the screenshot below, the PC has an IP Address of 10.101.19.20 and launched LightDesigner. The returned list shows a PCCS at 10.101.10.10 and the remaining are all PACPs.

BACnet

BACnet (Building Automation and Control Networks) is a protocol created in 1995 as ASHRAE-135, used to control/monitor multiple systems within a facility, including HVAC, fire/life safety systems, access control, energy utility/buliding integration, wireless communications, and lighting systems. BACnet supports multiple physical data link technologies.

BACnet/IP 

One of the data link technologies utilized by BACnet, and the only one supported by ETC products, including the Paradigm Central Control Server (P-CCS), Echo BACnet Interface (EBI), Mosaic Show Controller (MSC), and EchoFlex CAN2GO BACnet Gateway.

BBMD

BACnet Broadcast Management Device. Receives BACnet broadcast messages on one IP subnet, and forwards then to another subnet. Used as a special type of router to bridge BACnet messages across two networks.

Broadcast

Used to describe the transmission of data over a network. Broadcast is when network information from the source (transmitter) is sent to all devices on the network. Think of this like a flyer in the mail that gets sent to every home. This forces all devices to receive the broadcast information and do one of two things; either act on it (do an action) or ignore it (throw it in the invisible trash can). Broadcast storms often refer to instances when all the data on the network is being broadcast and forcing devices to spend all their time throwing away messages rather than doing their normal computing tasks. In the mail example with the flyers, its like spending all of your time throwing away flyers you are not interested in. This can result in slower response from devices or even device reboots.

Category Cables (Ethernet)

Over time, Ethernet-based networks have used different Category cables, expressed as "Cat#". Each variant has characteristics that (typically) allow for higher frequency transmission and bandwidth speeds over specific lengths of cable. Since 2001, Cat5e has been the most common, while Cat6 and Cat6a have become more frequent, as they are backwards compatible with Cat5/5e. A chart of some relevant information is found below:

Command Line Interface

CLI for short. A type of interface, often used to configure a device such as a network switch, in which commands are input via text. Examples include Command Prompt or PowerShell on Windows, Terminal on macOS, Bash on many Linux distributions, and the command line in Eos. A command line interface often contains the same or more options for configuration of a device than a graphical user interface (GUI) such as a webUI for a network switch. CLI commands use specific syntax and it is recommended to refer to a manual when first learning to use it.

Command Prompt

A command line interface available on Windows computers. The commands mentioned in this article reference those on a Windows PC. Commands for other operating systems (or other CLIs such as PowerShell) will vary.

The Command Prompt allows the user to enter commands written in specific syntax in order to return information about your computer or the network the computer is connected to. Command Prompt examples such as arp -a and ping are also defined in this article. To access the Command Prompt, press the Windows button and go to Run (Windows button + R shortcut). Next type in cmd and press Enter. This will launch a new window with a black background and a blinking cursor.

Console Port

A port used to configure a network switch. A typical managed network switch will have multiple methods by which to configure its settings. The most common is a web user interface, accessed by entering the switch's IP address into a Web browser. Managed switches may also offer a specific physical port on the switch hardware for switch configuration. On Cisco SG350 network switches, for example, the console port is an RJ45 port on the rear of the hardware. This port does not carry Ethernet communication, rather, it uses RS232 over an RJ45 to D-SUB 9 serial connector to establish a CLI between a computer and the network switch for configuration.

Core Switch

A switch used in a large Ethernet network to connect many switches to the same physical network.

DHCP

Dynamic Host Configuration Protocol. Used to distribute IPV4 addresses to devices on a network. DHCP requires that a server is present on the network and that a device is set up to configure its IP address automatically. When a device (known as a DHCP Client) needs an IP address, it can request one from the DHCP server, which will then lease an address to the client. The lease will expire after a period of time configured by the network administrator. Since a limited number of addresses can be used on a local network at a time, a network which expects many clients will likely have a shorter DHCP lease period. For example, in coffee shops, when connecting to wifi, the coffee shop will assign your device an IP address and will likely expire within 24 hours. At a home or office, the same process may include a lease that is good for a longer period of time like a month or a year.

In lighting systems, depending on the venue the network infrastructure, static IP addresses are preferred for permanently installed networked devices while the addresses for temporary devices such as DMX gateways or mobile devices running console applications are more frequently dynamic.

There can only be one DHCP server on a network but there can be many clients. If more than one server exists, unexpected results may occur. Note that the server should also be configured to lease IP addresses that are in the same IP subnet that is in-use by other devices on the network, otherwise network communication will not be possible.

ETC devices that can be DHCP servers include:  Eos Family Consoles, Cobalt Family Consoles, High-End Systems Hog Family Consoles, Conductor.

DNS

Domain Name Service. All IP communication happens between unique IP addresses, but these are not easy to remember, and an IP address may change without a user's knowledge. When a client (such as a Web browser) wants to connect to a server (such as the ETC website), it asks a DNS server to translate a human-readable domain (such as etcconnect.com) to an IP address that it can then communicate with.

While dedicated lighting networks often do not have a DNS server, many devices require a DNS server to be defined before they will allow network traffic of any kind. There are many public DNS server addresses that can be used as a placeholder in these cases.

EtherChannel

A feature in Cisco switches which allows multiple physical network ports between two switches to be treated as a single logical link, sharing their bandwidth. For example, 2 ports at 1Gbps could be linked together using EtherChannel to create a single link with 2Gbps total bandwidth.

Generically, this type of feature is called Link Aggregation.

Fiber Optic Cable

A type of Ethernet cable which sends pulses of light down fibers of glass for communication, as opposed to the electric voltages through copper used by traditional low voltage wiring. Has significantly higher potential bandwidth than copper cable, and can have significantly longer runs than Category cable, but is more expensive, more delicate, and requires specialized tools to install and maintain.

Fiber (Short Haul)

A fiber run generally under 10Km in length. Used in local networks. The light in a short-haul fiber run can be generated using low powered lasers or LED emitters.

Fiber (Long Haul)

A fiber run over 10Km in length to create large-scale communications infrastructure. Requires specialized cable, signal amplifiers and repeaters, and extremely precise lasers to propagate the signal.

Flow Control

Various methods to slow down the flow of data on a given communications link, so that a device that can send a lot of data does not overwhelm a device which cannot support that quantity of data.

GBIC

Gigabit Interface Converter. A piece of hardware which allows different types of cable, such as copper Category cable or multimode / single mode fiber, to connect to a single switch interface. Superseded by the SFP form factor.

HTTP

Hypertext Transfer Protocol. Primarily used by web browsers to access pages on the Internet, this protocol is a method for a client to make requests of a server and for that server to respond to those requests. In ETC products, this is most often used to access device web interfaces, but can also be used by technologies like the Mosaic API.

HTTPS

Hypertext Transfer Protocol(Secure). A revision of HTTP which implements encryption for added security, preventing devices from intercepting traffic between the client and server.

Hops

In a mesh-topology network, the number of times a particular signal is re-sent by a device. To prevent overcongestion, the number of hops a given signal can make in a mesh network is often limited with a TTL value. 

IGMP

Internet Group Management Protocol. This protocol is used to establish groups of multicast subscriptions on a network to reduce the bandwidth needs of multicast traffic.

IP

Internet Protocol. This protocol defines how messages are structured and sent between devices on a TCP/IP network.

Jumbo Frames

Ethernet messages, called frames, are limited by the Ethernet standard to 1500 bytes. A Jumbo Frame is one which exceeds that limit, and must be supported by the device on both sides of an Ethernet connection to be transmitted.

LAG

Link Aggregation Group. The group of physical ports used to create a single logical port via a Link Aggregation method such as Cisco's EtherChannel.

LAN

Local Area Network. A logical network made up of directly connected devices. Can be connected to other networks (a Wide Area Network or WAN) using a gateway.

In your home, the various network-connected devices in your home, such as your computer, phone, and smart fridge make up a LAN. The WAN they may connect to is the Internet, via the router or modem which acts as the gateway. If the WAN connection is disrupted, the devices on the LAN can still communicate with each other, so your phone can still see what is in your fridge, but your fridge cannot send an order for milk to the grocery store over the Internet.

MAC Address

A Media Access Control address is a unique numerical identifier for every physical network interface. It is represented as six octets in hexadecimal delineated by colons. Unlike IP addresses, MAC addresses do not change.

Managed Switch

Used to describe a network switch that is capable of having its settings or configuration altered using a web interface or Command Line Interface. Unmanaged switches will not have such an interface from which to alter its properties. Managed switches typically allow users to edit common features such as VLAN assignments on each port, Spanning Tree options for each port, and IGMP options for the switch. It is often advantageous to use a managed switch in a lighting network as opposed to an Unmanaged switch so that these properties can be altered to suit the needs of the devices living on the network. However a managed switch that is improperly configured can have undesired consequences for the devices on the network. It is important to understand what the network requirements are for devices living on a managed switch. For ETC provided network switches, visit this link for configuration guides. As always, feel free to contact ETC Applications Engineering for any questions about managed switch settings for ETC lighting networks.

MFA

Multi-Factor Authentication refers to any method which proves a user's identity using more than one piece of information, or "factor." A traditional user name and password has only one factor, the password, to prove that a user is who they say they are. An MFA login system may use a password as well as, for example, some proof that a user has an approved mobile device to make it more difficult to falsify the user's identity.

Multicast

One of several methods of transmitting data on a network.

Multicast traffic is sent to multiple devices on a network, but not to every device. For example, sACN is often sent by lighting controllers via multicast. If a controller sends data on Universe 1, only DMX Gateways programmed to output Universe 1 will receive those levels. DMX Gateways outputting Universe 2 would not receive those levels (unless it is a multiple-port gateway outputting both universes). 

In a TCP/IP network, multicast traffic does not require the source and destination devices to be in the same IP subnet.

On a managed switch, IGMP determines which ports receive multicast traffic, reducing the bandwidth used on any given network link. On an unmanaged switch, multicast traffic is broadcast to all ports, but receiving devices determine whether to act on it.

Any given type of multicast traffic, such as sACN, may have more than one source on a network. It is valid for two controllers, such as a lighting console and an architectural controller, to transmit data to a single DMX Gateway. A typical ETC network will have multiple simultaneous sources of multicast traffic.

Network Diameter

In computer networking, a network's diameter is the longest distance (as in the number of hops, not the distance in space) between two nodes.

Network Storm / Broadcast Storm

A condition in which excessive broadcast traffic on a network overwhelms network hardware. Often caused by a network loop: 2 ports on a switch connected to each other, each infinitely rebroadcasting the same packets they are sending and receiving. Network storms can be mitigated either by careful infrastructure planning or by technologies such as Spanning Tree Protocol.

Network Topology

Topology refers to the physical layout of computer networks of any kind. There are several topologies with their own applications, advantages, and disadvantages. For the purposes of this article, the word "node" generally means a network switch, but these topologies can be used to describe any form of networked communication, from DMX, to wireless systems, to analog telephone networks.

NIC

Network Interface Controller is the physical hardware that connects a device to a network through either a wired Ethernet cable, or wirelessly to a router or WAP (Wireless Access Point). Most modern devices have the NIC directly hardwired onto a motherboard or expansion card (PCI or PCI-E), but are also commonly found as external adapters via USB or Thunderbolt.

NTP

Network Time Protocol. A standard for synchronizing time between multiple computers on an IP network.

Octet

8 bits of data. Often referred to as a byte, but because "byte" did not always exclusively refer to 8 bits, "octet" is used when describing network addresses for the sake of specificity.

OSC

Open Sound Control. A protocol that defines the structure of messages that can be sent between multimedia devices. Often used to send commands between different types of entertainment control software, which may have no native interoperability, such as between Qlab and Eos, or to allow a user to create a bespoke interface to a piece of software. That interface could be as simple as a custom set of encoders on a tablet, or as complex as a system that detects the position of bodies in a space to dynamically adjust the lighting around them.

PIM

coming soon (Protocol Independent Multicast)

Ping

A command, implemented in the CLIs of most operating systems, which sends one or more IP "echo packets" to a given device and reports the reply. Any device that supports IP must reply to an echo packet, so a ping command can be used to verify basic, bidirectional, unicast connectivity between any two devices.

A ping command is typically structured ping {ip address}(e.g. ping 10.101.100.101),  and depending on the CLI in use, may be modified for different behaviors to fit different troubleshooting needs. For example, the Windows Command Prompt ping command will, by default, send four packets and report whether they were successfully replied to or if any errors occurred.

Note that because Ping is a unicast communication method, when troubleshooting a device on a local area network such as an isolated lighting network, the sending device and the replying device must be on the same IP subnet. 

Ping -t

In the Windows Command Prompt, the -t flag tells the utility to repeatedly send packets and report their replies until the user stops the command. This is useful for determining whether there are intermittent issues, such as a switch port or a flaky cable going in and out. A -t ping command is formatted:

ping 10.101.100.101 -t

Private / Public IP Address

Every physical NIC on a given IP network has its own IP address. When a LAN is exposed to the Internet, these devices should not have their IP addresses--called Private IP addresses--exposed. The router between the LAN and the Internet will assign IP addresses to each device that do not match their physical NIC's IP. These are called Public IP addresses.

PoE

Power over Ethernet. A blanket term that refers to many standards for delivering power over an Ethernet line. This eliminates the need to run an additional power line to a device when connected to a device that can supply PoE.

The original PoE standard IEEE 802.3af-2003 allows for up to 15.4W delivered over a single Ethernet line. 

PoE+

Defined in the standard IEEE 802.3at-2009. Allows for up to 25.5W of power on a line. A PoE+ port will negotiate with the device at the other end of the cable to determine how much power it needs. Therefore, a device that can be powered via standard PoE will work on a PoE+ port, but a PoE+ device will not work on a standard PoE port.

Proxy ARP

coming soon

QoS

Quality of Service. In computer networking, QoS refers to various methods of prioritizing data based on its application. For example, a router implementing QoS may prioritize streaming data, such as live video requiring high bandwidth and low latency, over less urgent data, such as standard Web traffic.

RJ11

A Registered Jack is a connection standard used in telecommunications that defines the physical connector and wiring configuration to connect two devices. RJ11, used for telephone connections, has a 6-position, 2-conductor connector. Colloquially, "RJ11" may refer to a 6-position connector populated with up to 6 conductors.

RJ45

"RJ45" refers to a connector with 8 positions and 8 conductors, also known as an 8P8C connector. These connectors are commonly terminated to category cable for Ethernet communications. Ethernet wiring using these connectors is defined by the ANSI/TIA-568 standard.

sACN

Streaming Architecture for Control Networks (a subset of the full ACN protocol) is a method for transmitting DMX levels over an IP network. (Note that sACN is distinct from and incompatible with DMX over CatV.) First approved by the Entertainment Services and Technology Association (ESTA) in 2009, it is currently defined by the ANSI E1.31-2018 standard.

sACN is transmitted by a source, such as a lighting console or architectural processor, over a TCP/IP network. Each packet contains the data for one universe of levels, or 512 addresses. The packets also contain additional information about which universe they belong to, their source, and their Priority.

An sACN receiver will interpret those packets and, based on its configuration, act on the data. A gateway or node will convert the data to DMX512 data to control other devices. Some devices, such as dimming racks and relay panels, complex multiparameter moving head fixtures, and media servers, are controlled directly via sACN on a network.

sACN is transmitted via UDP. Therefore, just like DMX512, a transmitting device has no inherent awareness of the device it's sending to, or whether the data is being received as expected.

sACN may be transmitted directly to a given IP address via unicast, but is typically sent via multicast. sACN universes range from 1 to 63,999. Each universe, when sent as multicast, is sent to its own multicast address, ranging from 239.255.0.1 to 239.255.249.255.

SNTP

Simple Network Time Protocol. A simplified version of NTP. Fully compatible with NTP, but lacks certain features, so it is theoretically less accurate but less demanding on the system on which it runs.

Spanning Tree Protocol (STP)

This is a mechanism in network switches that helps to prevent the retransmission of data in a closed Ring / Loop Topology. In this scenario, we will examine a simple system with 3 network switches connected to one another to for a Ring/Loop. Without Spanning Tree, data would flow endlessly around the circle and be re-transmitted indefinitely. Such behavior, also referred to as a Network Storm / Broadcast Storm can easily take down a network (network switches and edge devices such as consoles, controllers, and gateways). 

What Spanning Tree does is to block or close off one of the segments so the network is no longer a closed loop. The way it does this is by having one switch be the Root Bridge or center / leader of the switches and all other switches determine how far away they are from the center (Root Bridge), this distance is referred to as Path Cost. Whichever "network segment" has the highest path cost gets blocked and breaks the endless circle. The lowest cost path is the easiest path for traffic so those are left open.

Note:  For Cisco switches, individual ports on the network switches that connect to other network switches should have Edge Port disabled. All other ports that host nodes (gateways, controllers, edge devices) should have Edge Port enabled. See Edge Port definition for more details.

STP

Shielded Twisted Pair. A Twisted Pair cable uses two conductors twisted around each other to reduce electromagnetic interference from external sources, thereby increasing the potential bandwidth or reliability of the signal passed through those conductors. An STP cable adds a conductive material around the conductors, which helps absorb additional interference. To be effective, the shield must be connected to ground.

DMX cable, such as Belden 9729, is an STP-type cable. Pin 1 connects the shield to ground, while pins 2 and 3 carry the signal.

Twisted Pair cables without a shield are called Unshielded Twisted Pair, or UTP.

Storm Control

A setting on network switches that watches the quantity of packets traversing a physical network port (interface). If the quantity of packets per second exceeds a specified amount, the interface will dis-allow (block) packets until the quantity of packets decreases below the threshold. At that time, the interface allows traffic to resume (forwarding state). The quantity of packets per second and the hold interval are usually editable settings depending on the switch make and model. Storm Control, again depending on switch make/model, can be applied to unicast, multicast, and broadcast traffic (or combinations of).

Token Ring

Token Ring, developed by IBM, was a competitor to Ethernet. Before network switches, computer networking systems needed to manage data collisions: when more than one device tries to use the same physical hardware at the same time. When Ethernet detects a collision in an unswitched system, it waits for the collision condition to clear and then attempts to retransmit the data. This slows down the network, and the more complex a network is, the slower it gets.

Token Ring circumvented this problem by having each device on the network, connected in a ring topology, share a virtual token that allows a device to send a message only when it has claimed the token. This prevents network collisions at the cost of system complexity. 

TTL

Time To Live. Generically, TTL refers to the number of times a given signal can be repeated. This reduces traffic on any mesh network and can prevent a signal from being endlessly repeated.

An IP packet has a TTL value that determines how many times it may be passed from one router to another. Each time a router retransmits the packet, its TTL value decreases by one. If a router receives an IP packet with a TTL of 0, it will not be retransmitted, even if it has not yet reached its destination.

TCP

Transmisson Control Protocol. Along with UDP, one of the main data transmission protocols in the TCP/IP suite of protocols.

TCP is connection-based: two devices make a connection and then transmit data between each other. It is also "reliable," meaning the data transmitted over TCP must be verified and acknowledged by the device receiving it. If the data isn't acknowledged, the transmitting device resends it.

UDP

User Datagram Protocol.  Along with TCP, one of the main data transmission protocols in the TCP/IP suite of protocols.

UDP is not connection-based. A transmitting device will send UDP data to a destination on the network without verifying that the destination exists or is ready to receive data. The data is not acknowledged, so the transmitting device does not resend it if it is not received. 

Unicast

Used to describe the transmission of data over a network. Unicast is when two devices communicate with each other directly. Example, a lighting system has two controllers (either consoles or architectural controllers). In order from them to communicate with one another and synchronize information, they will send unicast messages directly to one another on the network. This is also commonly used with third party devices that wish to speak to ETC devices over the network. They will exchange unicast or UDP messages back and forth to perform a simple function like activating a cue or preset.

Unmanaged Switch

This is in reference to network switch hardware. An unmanaged switch does not allow for any of its properties, settings, or configuration to be edited. The most common example of an unmanaged switch is a 5-port or 8-port switch commonly found at local brick and mortar stores marketed for residential applications. A scenario in which this is advantageous may be for a small single switch network. If multiple switches are in use, Managed switches are always preferred. An unmanaged switch should not be used in a large network or a network with multiple switches as there is no way to edit common settings such as VLANs, Spanning Tree, or IGMP. 

Unregistered Multicast

"If no one asks for it, everyone gets it". If a multicast source like a console is sending out sACN lighting levels or other multicast information and there are no receivers or DMX Gateways asking for that universe, then that universe gets treated like broadcast and those lighting levels get sent to all ports. In small systems this is not an issue. On larger systems, that amount of broadcast can result in undesirable behavior. Example, network products have to discard all packets they receive that don't pertain to them, so a dimmer or relay cabinet has to spent more time discarding packets for universes that it doesn't care about then actually listening to the one or two universes it has patched to itself. Visible side effects of a "broadcast storm" may include sluggish or "laggy" response to level changes and even processor reboots. Using the post office analogy, a broadcast storm is like a mailer or leaflet that just gets sent to everyone, and everyone has to take time to receive the mailer and decide whether to read it (for the coupons) or throw it in the trash/shredder. 

Ideally an IGMP Querier will exist on a network that handles the multicast traffic and eliminates this. Unregistered multicast is traditionally set to Forwarding by default meaning that all unregistered multicast gets forwarded to all ports as described above. It is possible to configure network switch ports to instead Filter unregistered multicast. In a filtered environment, if the network port didn't ask for it, it doesn't get it. Cisco switches are able to configure Filter/Forwarding settings on a port by port basis.

Forwarding Example                                                                                                            Filtering Example

UTP

Unshielded Twisted Pair. See STP. A twisted pair cable without a shield.

VLAN

Virtual Local Area Network. A collection of ports on one or more managed switches that is treated as a standalone network. This allows groups of devices to have isolated network traffic without requiring multiple switches.

Wake on LAN

A device that supports Wake on LAN (WoL) may be woken from a low-power state via a particular Ethernet message (sometimes called a Magic Packet). This allows networked devices to save power by remotely powering on and shutting down.

WAN

Wide Area Network. See LAN.

Wildcard Mask

This is in reference to Wildcard Masks used in Access Control Lists. Most equate a Wildcard Mask as an inverted Subnet Mask whereas 255.x.y.z means that IPv4 traffic matching the first octet (for example 10.x.y.z) will be allowed/read by the receiving device. In a Wildcard Mask 0.255.255.255 means that the first octet (0) is the match/allowed and anything not 0 is ignored. This is somewhat true but there is more to it than that.

Real world example. sACN traffic. An Access Control List with an entry as follows:  Destination IP = 239.255.0.0 and Wildcard Mask of 0.0.255.255 means that any destination IPs of 239.255.0.0 through 239.255.255.255 will be watched. The first two octets are matched and the last two It's up to the programmer to choose whether to permit or deny those packets.

For a more detailed list of Wildcard Ranges related to sACN and Access Control Lists, see this article.