While WebRTC is a protocol designed to do one thing, and that is to provide highly secure, low-ping multimedia connections, one of its best qualities is its flexibility. Even if you're up for the rather articulate task of creating a video conferencing application, options are open to you.
You can switch to P2P, deploy a media server backend (there are quite a few of those), or mix and match these approaches as you see fit. You can select the features you want and find multiple ways to implement them. Finally, you can choose between a solid backend or a scalable media server grid built according to one of many templates.
With all that freedom at your fingertips, choosing the best option can be – and will be – difficult. Let's shed some light on the MCU vs. SFU for you.
Let's imagine it's Christmas. Or any other bulk gift occasion of your choice. You have a bunch of friends scattered all over town, but everyone is too busy to throw a gift exchange party. So you and your best friends agree that when they pass each other, they all get their gifts.
If you want to exchange something with your colleagues, whether it's a Christmas gift or a live video, the obvious way is definitely peer-to-peer.Each of your friends comes knocking on your door and gets your box, and then you all visit back. Clear and simple.
For a WebRTC chat, this means that all interlocutors are directly connected to each other, with the host serving only as a meeting point (or address book in our Christmas example).
This pattern works great while:
- Your group is quite small
- everyone is physically able to reach each other
Each gift in our example requires some time and effort to complete: you must at least drive to a location (or wait for someone to come to you), open the door, hand over the box, and say Merry Christmas.
- If there are 4 members in a group, each of you will need time to handle 6 gifts - 3 to give, 3 to receive.
- If there are 5 people, 8 gifts per person must be obtained.
- Once your party has grown to 6 members, your Christmas to-do list will now contain 10 gifts.
At one point there will be too many balls in the air: the amount of gifts received and sent will be too large to handle comfortably.
The same goes for video calls: each P2P transmission must be encrypted and sent or decrypted and viewedReal time- each operation requires a fraction of system performance, network bandwidth and battery capacity. This fraction might make sense for higher quality video: if a 2-on-2 or even 5-on-5 conference works decently on a relatively newer device, then a 10 on 10 point-to-point -FullHD call would consume or consume 50 Mbps of bandwidth and would tax even a mid to high level CPU.
Now for physical range. Imagine that one of your friends recently moved into a luxury condo. They are free to come and go - so they will come to your door to receive your gifts, but your chances of making it to their home to receive your gift are slim.
Regarding WebRTC, we are talking about corporate networks with NATs and/or VPNs. You can reach most hosts from within the network while being virtually inaccessible from the outside. Either way, your colleagues may not be able to see you, or vice versa, or both.
And last but not least - when everyone decides to stack the gifts for a fancy Instagram photo, everyone needs to come up with the stack of boxes and the photo: the gifts are at the recipient's house.
WebRTC: Peer-to-peer means no server-side recording (or other call-once features). No way.
Google Meet and secure mobile video calling apps without server-side features like video recording.
Here come media servers to save the day.
Back to imaginary Christmas. Your circle of friends is huge, so you imagine you'll spend all of Christmas waiting for someone or driving somewhere. To save you time, pay your local coffee shop to serve as a gift distribution hub.
From now on, everyone in your party must come to one place to leave or receive gifts - the cafeteria.
This is how WebRTC media servers work. They accept multimedia streams from callers and deliver them to everyone in a conference room.
Some time ago, WebRTC media servers came in two types: SFU (Selective Forwarding Unit) and MCU (Multipoint Conferencing \\ Multipoint Control Unit). To date, most commercial and open source solutions offer both SFU and MCU features, so both terms now describe features and usage patterns rather than product types.
Who are them?
What is SFU?
SFU sends separate video streams from everyone to everyone.
The café bartender keeps track of all gifts that arrive locally and calls recipients when something new awaits. As soon as you get that call, you go to the store, drink a pair of cotton pants, grab your box and go home.
The bad news is the bartender keeps calling you asking for one gift after another. So if there are three new gifts, then you have to do the path three times in a row. If it's twenty... you probably get it. Alternatively, you can visit the site from time to time and look for newcomers yourself.
As your gift spree prospers, so does the quality of the coffee: as more people join in, the bartender puts more time and effort into handing out gifts instead of caffeine. Remember: a gift - a call from the store.
The media server, acting as a selective forwarding unit, allows call participants to send their video streams only once - to the server itself. call.
With SFU, each client uses almost 2x less bandwidth, CPU and battery power than a point-to-point call:
- for a call with 4 users: 1 stream out, 3 in (instead of 3 in, 3 out for p2p)
- for a call with 5 users: 1 output stream, 4 input streams (would be 4 and 4 in p2p)
- for a call with 10 users: 1 out, 9 in (9 in, 9 out – p2p)
The downside kicks in when the user-per-call rate approaches 20. "Selective" in SFU represents the fact that this device doesn't rebroadcast media - it delivers media on demand. And since WebRTC is always a P2P protocol, each concurrent stream is a separate connection, even if a server is involved. So for a 10-user videoconference, a server must maintain 10 incoming (“receive video”) and 90 outgoing connections, each requiring processing power, bandwidth, and ultimately money. But…
SFU scalability
When the cafe owner is upset with the intensity of the gift exchange, you can take the next step and pay a few more stores in the neighborhood to participate.
Depending on the occupancy of a particular store, some of the gift givers or recipients may be diverted to another less crowded store. The grid can grow almost indefinitely, as each store can forward a package to its recipient or to an alternate collection point.
Forwarding rules are fully flexible. For example, Johnson's Coffee has gifts for your friends named A through F, and Smartducks is dedicated to packages for downtown residents, while Randy's Cappuccino is spreading its Merry Christmas to everyone who sent their first gift since last Thursday.
The Stream - A connection approach provided by the SFU standard has the function of overcoming almost all of its drawbacks. The feature is software development for scalability.
Just as you forward a user's stream to another participant, you can also forward it to another server. With this in mind, the backend WebRTC architecture can scale to grow or shrink based on the number of users, conferences and traffic intensity.
For example, if many clients request a specific flow from a host, you can create a new one, clone the flow there, and distribute it from a new unoccupied location.
Or, if you expect fast entry into a large conference (for example, about 20-30 streaming users and hundreds of view-only subscribers), you can allocate two separate media server groups, one to handle incoming streams. and the other deliver it to subscribers. In this case, peak loads on the screen side will not affect video recording, and vice versa.
Examples of application of the SFU
Skype and almost all other mobile messengers with video conferencing and video call recording features use the SFU standard in the backend.
Receiving videos from other users as separate streams provides adaptive UX features, allows per-stream quality adjustment, and improves overall call stability in a volatile cellular network environment.
MCU combines all streams into 1 and sends only 1 stream to each participant.
Giving is making friends, isn't it? Now almost everyone in town is his friend and participates in this gift exchange. The coffee shop hosting the exchange has a great idea: why not put all the gifts for a certain person in a giant box with that person's name on it? There's also some Christmas magic at play right now: as soon as there are new presents for everyone, they'll automatically appear in their respective boxes.
Still, it looks like making Christmas magic is harder than making coffee: they might even have to hire more people to enchant the gift boxes. And even with additional assistants on call, there's no chance you'll rearrange the order of the contents in the boxes so your significant other sees your gift first - they all get the same pattern.
Well, some of the MCU-related features actually call for puns on an acronym shared with the Marvel Cinematic Universe. Something wonderful is definitely at stake. Media servers in an MCU role only need to maintain 20 connections for a 10-user conference instead of the 100 connections for an SFU - one write, one output per user. From where? It merges all the videos and audios that a user needs to receive into a single stream and delivers it to a specific client. Here's how Zoom conferencing works: With the MCU, even a low-end computer can handle a live call with 100 users.
However, magic obviously comes at a price. Gathering multiple video and audio streams together in real time is *much* more of a performance hog than any routing pattern. Even more so if you somehow need to exclude your own voice and image from the merged grid they get - for each of the users.
Another downside, albeit a minor one, is that a composite grid is the same for everyone receiving the video - regardless of screen resolution, aspect ratio or anything else. If different mobile and desktop layouts are required, you will need to splice the video twice.
For WebRTC video calls, the MCU standard has significantly less scaling potential compared to SFU: compositing video with delays of less than one second does not allow for spontaneous load rebalancing for a given conference. However, you can automatically create additional server instances for new calls in a virtualized environment or allocate an additional SFU unit to redistribute composite video for even greater efficiency.
Zoom and many of its massive videoconferencing alternatives run from MCU-like backends. Otherwise, WebRTC video calls for 25+ participants would only be available for high-end devices.
~1-4 users per call - P2P
Benefits:
- lower idle costs
- easier scale
- menor TTM (time to market)
- possibly the safest
Disadvantages:
- for calls with more than 5 users - quality may deteriorate on weaker devices
- Higher bandwidth usage (can be critical for mobile users)
- no server-side recording, video analytics or other advanced features
Forms:
- private \ group calls
- Video support and sales
5-20 users per call - SFU
Benefits:
- easily scalable with concurrent numerical growth
- maintain user experience flexibility while providing server-side features
- may have node redundancy by design: hence the most failsafe
Disadvantages:
- Lots of traffic and intensive performance on the client side
- May still require MCU-like compositing service to record calls
Use cases:
- E-learning: workshops and virtual classes
- Corporate communication: meeting and press rooms
20+ users per call – MCU \ MCU + SFU
Benefits:
- Lower load on client-side devices
- able to serve the widest audience
- easily writable (server side / client side)
Disadvantages:
- higher idle and operating costs
- The capacity of a call is limited to the performance of a specific server
- less customizable layout
Use cases:
- Broadcast of big events
- social network
- online media
P2P, MCU and SFU are part of WebRTC. For more information about WebRTC, visit our blog:
How to minimize latency for bulk streams to less than 1 second?
WebRTC no Android.
WebRTC security in plain language for business people.
Do you have another question that isn't covered here? Please feel free to contact us usingthis shape, and our professionals will be happy to help you with anything.
FAQs
What is P2P vs SFU vs MCU? ›
MCUs differ from Peer-to-Peer (P2P) connections, in which each party sends and receives media directly to and from the other party. They are also different from Selective Forwarding Units (SFUs), which receive media from each party and then decide which streams should be forwarded to other parties.
What is SFU in video conferencing? ›SFU (Selective Forwarding Unit) is a video conferencing architecture which features the following data transmission processes between the server and the endpoints: 1. The server receives incoming video streams from all endpoints.
What are the advantages of SFU? ›The main advantage of the SFU architecture is the ability to work with asymmetric bandwidth, or higher downlink bandwidth than uplink bandwidth. Because of this, it it suitable for asymmetric uplink/downlink networks, e.g., ADSL, Mobile, and Cable.
What is an SFU? ›SFU stands for Selective Forwarding Unit. Also known in the specifications as SFM (Selective Forwarding Middlebox). At times, the term is used to describe a type of video routing device, while at other times it will be used to indicate the support of routing technology and not a specific device.
Does zoom use MCU or SFU? ›Beyond MCU
Zoom has chosen a unique technology called the Multimedia Router. Essentially, it is a distributed version of SFU, where Zoom takes one uplink from each client and multiple downlinks to each client.
Also a significant difference between the MCU and the MEU is the format of solo outings of their heroes. While the MCU films are grouped into phases, with each hero having one film in each phase, the MEU films will also include solo outings in its Marvel Anthology line.
What are the 2 main types of video conferencing systems? ›- Telepresence Video Conferencing System: Multiple screens or monitors are used to make everyone feel like they're joining the meeting in person.
- Desktop Video Conferencing System: All the video conferencing hardware and software is built-in to a computer or laptop.
Multipoint Control Unit (MCU) is a video transcoding server that manages multiple SIP/H 323 endpoints simultaneously, coordinates data processing between them, and forwards media streams during a video communication session. MCUs can be either hardware or software deployed in a virtual environment.
What is SFU zoom? ›SFU Zoom is available to all faculty, staff and students for real-time online teaching, meeting and learning. You can log in SFU Zoom using your Computing ID and passwords. Learn more about SFU Zoom features.
What is the advantage and disadvantage of using a thick fuse wire? ›The resistance is inversely proportional to the cross-section of the wires used, so thick wires mean low resistances. So, even if high current flows through the fuse, it will not melt thus causing damage to electrical devices during faults. This is the disadvantage of using thick fuse wires.
What program is SFU known for? ›
- Computer Science.
- Engineering.
- Health.
- Social Science and Humanities.
| Letter Grade | Numerical Equivalent | Definition |
|---|---|---|
| B+ B B- | 3.33 3.00 2.67 | good performance |
| C+ C | 2.33 2.00 | satisfactory performance |
| C- D | 1.67 1.00 | marginal performance |
| F | 0.00 | fail (unsatisfactory performance) |
The 13 weeks during which classes are held. SFU's three terms begin in September (Fall term), January (Spring term), and May (Summer term). Intersession is eight weeks in May and June, and Summer Session is six weeks in July and August. Each term has its own enrollment and exam period.
How do I get SFU? ›Most experts think that flu viruses spread mainly by droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby (usually within about 6 feet away) or possibly be inhaled into the lungs.
How does SFU internal transfer work? ›If you are currently an SFU student and interested in transferring to any of the BPK Programs (all majors, minors, certificates), then you will need to apply for an internal transfer. Admission via this route is competitive, and is based on your GPA in select courses completed in your first semesters at SFU.
What are the advantages of using software based MCU? ›Advantages of the MCU architecture
Does not require wide bandwidth for the client. Bitrate does not depend on the number of participants, but on the amount of the data sent and received. The client connects to the media server, not directly to other participants. Server-side recording is available.
The desktop app is available for Windows and macOS, while the mobile app is available for Android and iOS. The desktop app offers the best experience. All the apps let you join a meeting without signing in, but also let you sign in using a Zoom account, Google, Facebook, or SSO.
How do you explain MCU to someone? ›The Marvel Cinematic Universe is a collection of movies and television series that tell a singular narrative related to Marvel characters, settings and stories. The MCU is a product from Disney and Marvel that brings us heroes from Black Panther and Doctor Strange to Spider-Man and Iron Man.
What is the overview of MCU? ›The Marvel Cinematic Universe (MCU) is an American media franchise and shared universe centered on a series of superhero films produced by Marvel Studios. The films are based on characters that appear in American comic books published by Marvel Comics.
How does the MCU work? ›The answer is simple: It's controlling the hardware that implements the device's operation. The MCU receives inputs from buttons, switches, sensors, and similar components; and controls the peripheral circuitry—such as motors and displays—in accordance with a preset program that tells it what to do and how to respond.
How do I choose a video conferencing system? ›
- Remember the Resolution. The quality of video that we can achieve in our conferencing environments is increasing all the time. ...
- Look for Value-Adding Features. ...
- Check Advanced Capabilities. ...
- Consider Security and Privacy. ...
- Ensure Ease of Use and Adoption.
- Zoom.
- Microsoft Teams.
- Skype.
- Webex Meetings.
- BlueJeans Meetings.
- GoTo Meeting.
- Google Workspace.
- Webex App.
- Zoom: Best Overall Video Conferencing Solution.
- Google Meet: Best One-Stop Shop Video Conferencing Software.
- TeamViewer Meeting: Best for Collaborative Meetings.
- Zoho Meeting: Best for Growing Team.
- CyberLink U Meeting: Best for Image-Conscious Professionals.
A multipoint control unit (MCU) is a type of video conferencing hardware that bridges terminals involved into a multi-point conference system. MCU makes it possible for a multipoint audio/video conference to be controlled and moderated from a single location.
Why is it called the MCU? ›Later during the press promotions of Iron Man 2, Feige changed words and referred to the franchise as Marvel Cinematic Universe for the first time. It was a time when Iron Man 2 was awaiting its 2010 release and Marvel Studios had already been acquired as a whole by Disney.
What is the main MCU? ›In the fictional Marvel Comics multiverse, Earth-616 is the primary continuity in which most Marvel Comics titles take place.
What is the difference between Zoom com and zoom us? ›The fact Zoomus.com is owned by a legit business wasn't Zoom's only stroke of luck. If you type Zoom.com in your web browser, the URL redirects you to Zoom's website at Zoom.us.
How do I log into SFU Zoom? ›Go to https://sfu.zoom.us/ and sign in with your SFU Computing ID and password.
Why do I have to pay for Zoom? ›Zoom's free license gets you into the video conferencing game, but a paid Zoom One account gives you a front-row seat to productivity, efficiency, and employee success with greater control and enhanced functionality.
Why do you think it is better to use thicker wire? ›The thin wire will conduct electricity, but there is more electrical resistance. The thicker wire is like the four lane highway. There's a lot less electrical resistance, and as a result, that light bulb burns brighter because more electricity can reach it.
What are the two most important requirements of a fuse wire? ›
Essential requirements for a fuse wire must have high resistance and low melting point.
What are the advantages and disadvantages of using a fuse and circuit breaker? ›Fuses can require larger wiring to compensate for inrush current. A circuit breaker can provide ground fault protection, a fuse cannot. Fuses “age” and degrade over time which can cause nuisance tripping. Single phasing on three-phase loads does not happen with a three-pole circuit breaker.
Is SFU difficult to get into? ›Most SFU programs require you to have completed a few specific high school courses. They also require you to achieve a minimum grade point average (GPA). This minimum GPA is typically around 70% to 80%. However, we recommend aiming for a GPA in the 90% range to be a competitive candidate.
What is 60% at SFU? ›| Letter grade | SIAT recommended % grade | Definition |
|---|---|---|
| C+ | 65-69.5 | Satisfactory performance |
| C | 60-64.5 | |
| C- | 55-59.5 | |
| D | 50-54.5 |
...
To convert your GPA to a 4.0 scale:
If you are not in good standing or have a GPA or less than 2.0 (60%), you will not be admitted. Admission is competitive. Admission averages have ranged from 2.50 GPA to 3.50 GPA depending on the program - for details see admission averages. An admission average is calculated on all transferable courses attempted.
How long is a program at SFU? ›Simon Fraser University offers three full terms or semesters within the twelve month calendar year. The calendar year is divided into three academic terms of 16 weeks each. Each term has its own enrolment and final examinations.
What does units mean SFU? ›A student studying for a bachelor's degree or certificate. Unit. The credit you will receive toward completing your degree. Each SFU program requires a certain number of units. Courses indicate the number of units they are worth, for example English 104-3 gives you 3 units toward your degree.
What is full-time SFU? ›Full-time Status
Undergraduate students who are enrolled in at least 60% of a full-time course load, and in a student loan eligible program, are considered to be studying full-time. At SFU, this means a minimum of 9 units per term (15 units is considered a 100% courseload).
The application portal opened for the Fall 2023 intake on October 17, 2022 at midnight (PST). The application deadline is Sunday, January 29, 2023 at 11:59 PM (PST).
How do I check my SFU application? ›
After you've applied — and goSFU (applicant.sfu.ca)
Application status updates will appear on your Student Center (goSFU): Spring term (January): Admission offers are made from September to November.
Ready to start your graduate student experience at Simon Fraser University? There is no general admission at the graduate level at SFU, as admission is specific to each program. You may apply to as many programs as you wish within an application period.
Should I negotiate internal transfer offer? ›Accept The Offer And Do Salary Negotiation
Typically if it's the same job title, you don't get a raise for internal transfer and you don't need to sign a new offer. However if you change job titles during the internal transfer, they will ask you to sign a new offer, then the offer package is negotiable.
A transfer will not necessarily result in a higher salary, although it can if the transfer is really a promotion, or if the other workers doing the same job make more money than the transferring employee.
When should I ask for an internal transfer? ›Do you believe that there is a better job scope for you in a different department? Is there a different internal position that will allow you to evolve and grow? If you answered yes to any of the above, then it's time to request for an internal job transfer.
What does MCU mean in TV? ›The Marvel Cinematic Universe (MCU) television series are American superhero television shows based on characters that appear in publications by Marvel Comics. They are set in, or inspired by, the shared universe of the MCU film franchise.
What is MCU mode? ›MCU Mode ( Mackie Control Universal ) was introduced in 2003 as a proprietary MIDI communications protocol combining together functionality from Mackie Control, Logic Control, and HUI into a single protocol typically used with Logic, Cubase, Ableton Live, and Sonar.
What does MCU stand for in TV? ›Marvel Cinematic Universe (MCU).
The movies are the series of live action films from Iron Man (2008) through Spider-Man: Far From Home (2019). The shows include things like Agents of S.H.I.E.L.D., Agent Carter, and WandaVision.
Higher returns to the investors: P2P lending generally provides higher returns to the investors relative to other types of investments. More accessible source of funding: For some borrowers, peer-to-peer lending is a more accessible source of funding than conventional loans from financial institutions.
What is an advantage of the peer-to-peer network model? ›A peer-to-peer network is a technology that allows you to connect two or more computers to one system. This connection allows you to easily share data without having to use a separate server for your file-sharing.
Where P2P network is most preferable? ›
This type of P2P network is often used in applications such as online marketplaces, where a central server is needed to manage transactions and user authentication, but direct communication between users is also desirable.
What are MCU used for? ›An MCU is an intelligent semiconductor IC that consists of a processor unit, memory modules, communication interfaces and peripherals. The MCU is used across a broad range of applications, including washing machines, robots, drones, radio and game controllers.
What does MCU mean in video? ›A multipoint control unit (MCU) is a type of video conferencing hardware that bridges terminals involved into a multi-point conference system. MCU makes it possible for a multipoint audio/video conference to be controlled and moderated from a single location.
Why does MCU mean? ›The Marvel Cinematic Universe - or MCU for short - is the shared place where all 22 films featuring the comic book characters are set. Each tells its own distinct story but also connects with other films in the MCU, to tell an overarching tale.
What is an MCU platform? ›A microcontroller unit (MCU) is a small, self-contained computer that is housed on a single integrated circuit, or microchip. They differ from your desktop computer in that they are typically dedicated to a single function, and are most often embedded in other devices (e.g. cellphones; household electronics).
What are the three phases of MCU? ›How many Marvel phases are there? And do you have to watch the movies in order? The audio versions of each Marvel phase make great introductions to the MCU. You'll meet Captain America and the Incredible Hulk in the Phase One Box Set; Ant-Man in the Phase Two Box Set; and Doctor Strange in the Phase Three Box Set.
Why is MCU popular? ›The Solution. The Marvel Cinematic Universe, perhaps the most successful franchise of all time, strikes the right balance by (1) selecting for experienced inexperience, (2) leveraging a stable core, (3) continually challenging the formula, and (4) cultivating customers' curiosity.
Do I need to watch all MCU? ›If you haven't watched the MCU films before, I would recommend that you stop reading here and go watch the films. The 13 films in the speed round are the most essential, but I do highly recommend watching all 23 to get the full experience.