https://github.com/princeton-cabernet/scallop
WebRTC Selective Forwarding in the Data Plane
https://github.com/princeton-cabernet/scallop
p4 sdn sfu tofino video-conferencing webrtc
Last synced: about 2 months ago
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WebRTC Selective Forwarding in the Data Plane
- Host: GitHub
- URL: https://github.com/princeton-cabernet/scallop
- Owner: Princeton-Cabernet
- License: agpl-3.0
- Created: 2025-08-12T18:02:02.000Z (3 months ago)
- Default Branch: main
- Last Pushed: 2025-08-19T21:02:25.000Z (2 months ago)
- Last Synced: 2025-08-19T21:28:55.083Z (2 months ago)
- Topics: p4, sdn, sfu, tofino, video-conferencing, webrtc
- Language: C++
- Homepage:
- Size: 454 KB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://github.com/Princeton-Cabernet/scallop/actions/workflows/build-test-controller-agent.yml)
[](https://github.com/Princeton-Cabernet/scallop/actions/workflows/build-test-client.yml)
**Abstract.** This project rethinks the key building block for video-conferencing infrastructures - selective forwarding units (SFUs). SFUs relay and adapt media streams between participants and, today, run in software on general-purpose servers. Our main insight, discerned from dissecting the operation of production SFU servers, is that SFUs largely mimic traditional packet-processing operations such as dropping and forwarding. Guided by this, we present **Scallop**, an SDN-inspired SFU that decouples video-conferencing applications into a hardware-based data plane for latency-sensitive and frequent media operations, and a software control plane for the (infrequent) remaining tasks, such as analyzing feedback signals and session management. Scallop is a general design that is suitable for a variety of hardware platforms, including programmable switches and SmartNICs. Our Tofino-based implementation fully supports WebRTC and delivers 7-422x improved scaling over a 32-core commodity server, while reaping performance improvements by cutting forwarding-induced latency by 26x.
**Paper.** The code in this repository supports the research presented in our paper that provides a comprehensive introduction to Scallop:
> Oliver Michel, Satadal Sengupta, Hyojoon Kim, Ravi Netravali, and Jennifer Rexford. 2025. Scalable Video Conferencing Using SDN Principles. In ACM SIGCOMM 2025 Conference (SIGCOMM ’25), September 8–11, 2025, Coimbra, Portugal. ACM, New York, NY, USA, 19 pages. https://doi.org/10.1145/3718958.3750489
## Building the code
### Controller and Switch Agent
```shell
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j$(nproc)
```
### Data Plane
### Client Application
```shell
cd client
npm install
npm run build
```
## Create certificate
* for *localhost*:
```shell
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem \
-days 365 -nodes -subj "/CN=localhost"
```
## Run Scallop
### Controller
```shell
build/controller/controller
```
### Tofino Agent
```shell
build/agent/tofino_agent -l
```
### Tofino PRE Adapter
...
### Client
...
## Demo VM for SIGCOMM 2025 Artifact Evaluation
We provide a demo virtual machine for the SIGCCOMM '25 Artifact Evaluation on AWS EC2. In this
section of the README, we explain the steps required to execute to log in to the EC2 instance,
run Scallop and conduct a video conference that uses the Intel Tofino software model.
### Step 1: Logging into the AWS EC2 Instance
1. Paste the SSH private key available on HotCRP into a file called `scallop-demo-key.pem`.
2. Move this file to your system's `.ssh` directory by executing in a terminal:
```bash
mv scallop-demo-key.pem ~/.ssh/
```
3. Change the file permissions of the SSH key file to one permitted by AWS, by executing in a terminal:
```bash
chmod 400 ~/.ssh/scallop-demo-key.pem
```
4. Log into the EC2 instance by executing in a terminal:
```bash
ssh -i ~/.ssh/scallop-demo-key.pem ubuntu@demo.p4-sfu.net
```
5. Retrieve the VNC password by executing in a terminal:
```bash
cat ~/VNC_PASSWORD.txt
```
### Step 2: Connect to the EC2 instance using VNC
1. Forward the VNC port (5901) from the EC2 instance to your local machine by executing in a terminal:
```bash
ssh -i ~/.ssh/scallop-demo-key.pem -L 5901:localhost:5901 ubuntu@demo.p4-sfu.net
```
2. Open a VNC client on your local machine and connect to `localhost:5901`
3. Enter the VNC password retrieved in Step 1, and you should see the desktop of the EC2 instance.
### Step 3: Start Scallop
1. In your SSH session, navigate to `~/opt/scallop`
```bash
cd ~/opt/scallop
```
2. Start the Scallop controller by executing:
```bash
build/controller/controller
```
## License
This project's source code is released under the [GNU Affero General Public License v3](https://www.gnu.org/licenses/agpl-3.0.html). In particular,
* You are entitled to redistribute the program or its modified version, however you must also make available the full source code and a copy of the license to the recipient. Any modified version or derivative work must also be licensed under the same licensing terms.
* You also must make available a copy of the modified program's source code available, under the same licensing terms, to all users interacting with the modified program remotely through a computer network.