Flexible cloud networks are the key to application performance and access.

The basic value of cloud computing comes from flexible storage and server resource pools, while cloud networks are the key to this model. Without proper network connections, servers and storage cannot form a pool and users cannot link to their applications. Enterprises that transition to cloud computing must consider new network design and connections, as well as service quality QoS management, so that they can integrate private and public cloud resources to ensure optimized application performance.

Application access: VPN vs. Virtual Data Center

Cloud computing must combine employees' inherent views on its applications with the flexible perspectives on where these applications are located and how they run. The work of cloud networks is to support this purpose. There are two main options for integrating cloud resource pools: one is to establish a "virtual data center", which is linked to the enterprise data center and controller. This can be a software element or a Server Load balancer switch) implemented by the public cloud resources behind it, which provides users with application access. Another method is to createVPNTo connect applications and users, regardless of where the applications and users are hosted. Both options have their own advantages and limitations.

When the "manager" controls cloud resources, all application access is managed by this "manager. However, when the actual resources are widely dispersed, this may be a problem, because some users may have a network connection to directly connect to resources, which is better than controller connection, and, additional hops may cause latency and performance problems. When cloud resources are collected in a small area such as a metro network, the virtual data center mode is the best mode.

The advantage of the VPN method is that users and users can access each cloud host in a unified manner, but this method also has problems. First, all VPN and channel technologies in a private network must be used effectively by cloud-hosted routers in hybrid cloud applications. BGP termination, MPLS Label Edge Router LER) functions and other virtual network technologies are generally unavailable on routers, and cloud providers cannot support the router hardware installed by users. In addition, there are potential sequential failover and overflow problems, because load balancing is not a normal property of VPN. The good news is that there are emerging solutions on the market that can help optimize the efficiency of VPN in the cloud environment.

Use SDN to connect to cloud Resources

An emerging method for connecting to cloud resources is to use software defined network (SDN), especiallyOpenFlow ProtocolTo establish a link between the static application address and the actually hosted resource of the application. Most major switches/routers support this function, so this policy can be compatible with existing data centers and WAN network devices used by most enterprises. Some SDN vendors may also provide applications and tools to promote such network virtualization. Generally, network virtualization tools can help organizations map dynamically allocated resources to applications if they are in a cloud environment.

Ensure the quality of experience, regardless of the location of users and cloud Resources

Public and private network Cloud resources) A common problem is to ensure the quality of application experience QoE) There will be no huge difference due to resource allocation. A real cloud "resource pool" should be able to serve any user combination application and have QoE comparable to it, which means that all the paths between resources and connections from all users to resources are allowed, has a network connection with good QoS.

VPN can be used to connect all cloud components, including users. However, when the cloud data center is located in the LAN, it is best to use VPLS or other virtual LAN services to connect the data center to the virtual data center. This is especially true when internal processes or storage traffic are expected to innovate.

Not all cloud providers can add their cloud services to VPN, and not all cloud providers support VPN. Since each private cloud should be regarded as the beginning of a hybrid cloud relationship, it is recommended that you carefully check the available public cloud in the dominant position before signing the contract, to ensure compatibility with VPN candidate solutions.