# Scheduling for Media Function Virtualization
## 3 Related Works  
Broadcast media production is undergoing a massive transformation propelled by IP and virtualization technologies. The migration to IP-based media transport from SDI is expected to accelerate in the near future. The interest in IP among broadcasters is emphasized by the fact that the SMPTE has released a suite of ST 2110 standards [8; 9; 10]. These standards describe how different media essences, i.e., video, audio, and ancillary data, can be transported independently using IP. Many all-IP broadcast studios are now being built based on these standards.  
A live TV broadcast based on IP was produced by the British Broadcast Corporation (BBC) during the Glasgow 2014 Commonwealth Games [11]. UHD streams captured by multiple cameras in several competition venues were delivered to the software-defined production facility. The final program, after HEVC, was also delivered over IP. Likewise, a new broadcast facility in Wales, UK was built based on IP.  
The Canadian public broadcaster CBC/Radio-Canada has constructed an all-IP facility responsible for over 100 TV, radio, and online program in Montreal, Canada [12]. The switching network is based on leaf-spine topology with 100 Gbps links. The network can support real-time multicast traffic along with redundancy for media streams. The software-defined network ensures that media streams can be distributed uniformly over the topology. The flexibility offered by IP is crucial for COTS-based media processing, as discussed next.  
[PERSON] et al. have also demonstrated the PoC for a vision mixer based on open-source software tools (e.g., OBS studio and KX studio) running on a COTS hardware platform [13]. They presented a low-cost replacement for a specialized hardware production system. The evaluation shows that the vision mixing setup has an acceptable delay of about 1.4 s, which is reasonable for professional (nonlive) media production scenarios. Furthermore, live media mixing based on software has been demonstrated by the BBC partnered with Isotama [14]. To operate the setup in real time and control the final live output, the software pipeline is interfaced with a browser-based operation tool.  
Broadcast media services in an MFV environment can be represented using VMF-FGs. In our previous work, we proposed a VMF-FG decomposition algorithm [15]. The VMF-FG decomposition algorithm processes an input VMF-FG to produce an optimized VMF-FG that consumes fewer resources.  
Recently, some work has been done to address the joint routing and scheduling problem for DetNets [16]. The problem is formulated as an integer linear program (ILP) and two methods--column generation and dynamic programming--are proposed to maximize traffic acceptance. An ultrafast and scalable greedy heuristic that is capable of solving the problem with a small penalty is also proposed. In this paper, the DetNet requests are simply two endpoints (source and sink). The problem of VMF-FG scheduling assumes a timing relationship between different virtual links. To the best of our knowledge, there has not been any research on scheduling VMF-FG to reliably deploy media services. This work aims to first formulate the VMF-FG scheduling problem and also proposes a heuristic to solve it.