# A Study on Design Requirement Development and Satisfaction for Future Virtual World Systems
## 5 Discussion
### A Possible Avenue Towards Future  
As no existing architecture can fully satisfy all new requirements, is it to possibly leverage their advantages to create a new one? For answering this question, a new architecture called Virtual Net is under development to satisfy more requirements [126]. The central idea of Virtual Net is that nobody owns a virtual world, but all users collectively create a selforganized one. Thus, Virtual Net belongs to the decentralized architectures. In Virtual Net, users contribute a part of their computingresources, which is virtualized into one or multiple virtual nodes. All virtual nodes have the same computing resources, managed by a node pool. Users of Virtual Net can store their contents or deploy their applications on the nodes without a central server. Thus, it can inherit the advantages of the decentralized design paradigm in persistency, data security, and legal protection.  
In the Virtual Net architecture, a Mesh is a set of replicated virtual nodes. One Mesh is assigned to each user for running virtual world applications. The replicas in a Mesh apply a replica synchronization protocol to maintain replica consistency. Thus, externally, each Mesh can be treated as a reliable peer, and inter-Mesh interaction is equivalent to the interpeer interaction in the P2P architecture. In a Mesh, a client is a special node, which provides the user interface for receiving user operations and rendering updated states to users. A Mesh can receive the operations from or send updates to a client. This type of structure offloads the computational complex tasks from the client to the remote service end. So, a lightweight client device only needs to concentrate on limited computing tasks. Moreover, a client can simultaneously communicate with all the replicas of a Mesh to provide connection failure tolerance. Thus, the overall reliability of Virtual Net is higher than the existing architectures. Notably, a special Mesh is assigned to an NPC for running the AI program, which does not have a client node. Virtual Net also contains a P2P cloud that provides the common services needed by all Meshes, such as object request routing [148].  
A full comparison of Virtual Net with other architectures is shown in Table 2. In addition to the above features, Virtual Net also has some advantages in scalability and cheating prevention. The scalability cost of Virtual Net is a bit tricky. It depends on whether an application provider contributes any virtual nodes to the node pool. Thus, it is equivalent to the cost of the Hybrid-II model. With respect to cheating prevention, Virtual Net can mitigate client-side code tampering by detaching the service from the client device. Though an attacker can still break the program running on his/her device, through random node allocation, the resources of the device are most likely not assigned to his/her Mesh, which minimizes the value and incentive of such attack.  
Though promising, a full-fledged Virtual Net requires various challenges to be resolved, including virtual resource management, rapid replica synchronization, composition of event handling, and object simulation. Currently, the Virtual Net research is making progress [149] and we can anticipate a better future of virtual worlds.