How to "arm" the IPv6 data center

As early as the formation of IPV6 technology, people have begun to study and demonstrate the transition, coexistence, and interconnectivity of IPv4/IPV6 networks, it focuses more on how to smoothly migrate from a traditional IPv4 network to the ultimate IPV6 network at the basic network layer.

When IPV6 applications are deployed in the data center or an IPV6 data center is built, the data center construction idea is different from that of other networks. Because the data center ultimately needs to provide IPV6 services in an all-round way, IPV6 is the core goal of the data center, and IPv4/IPV6 provides comprehensive external services under the current conditions at the same time.

Current Basic Application of IPV6

At present, IPV6 applications in the network are mainly engaged in FTP, WEB services, VOD, file sharing and other services. Such services have certain requirements on network bandwidth and have no high requirements on the server's computing power.

From the perspective of more mature row-based application computing, the general applications are multi-tier (N-tier) architecture, such as the common C/S architecture and B/S multi-tier application mode, figure 1.

Figure 1 layered architecture of traditional applications

In the traditional IPv4 network environment, the multi-layer software system is very rich and mature, especially the rapid development of middleware. Currently, a large number of enterprise-level computing systems use middleware to implement a wide range of data center services. For upper-layer applications, IPV6 only replaces the network communication layer and only involves modifications to the underlying protocol stack. However, the large-scale computing system based on IPV6 underlying communication is not truly mature, for example, IPV6 operations supported by various databases have matured in the last two years, and the communication level of enterprise core system software is in the early IPV6 transition period.

Build flexible and scalable data centers for Applications

To build a data center that can support future IPV6 applications, you must consider the specific deployment requirements of the application system.

In many system construction systems, people will simply choose the "dual-stack host" method. This may be a reasonable choice for small and simple applications, but for large-scale computing applications, this simple deployment requirement may lead to more investment costs and continuous O & M costs. This is because the multi-layer architecture software system is not complete at all levels in support of the double stack, especially the intermediate computing platform. Due to the wide variety of software and rich functions, currently, there are not many dual-stack support (in contrast, multi-layer architecture applications can implement IPV6 frontend services on the WEB layer, and IPv4 backend operations may become a better method of transition ). Therefore, to make all components of the application system fully turn to IPV6, the technical maturity will be a big problem, and the complexity of system O & M will be greatly improved compared with the traditional environment. The WEB computing layer of the B/S architecture is easier to implement dual-stack because it has relatively simple functions and provides operations for client terminals, as shown in figure 2.

Figure 2 IPV6/IPv4 Dual-stack access at the WEB server layer

The dual-stack server deployment policy at the WEB layer helps improve data center compatibility and scalability. For IP addresses, the addresses occupied by end users, networks that carry user traffic, and the WEB service layer of data centers (Figure 2) are the main IPV6 network architecture, the middleware application server and database server after the WEB layer do not provide direct services to end customers, so as to maintain a mature IPv4 communication system. Based on this method, there are flexible and scalable options for supporting application deployment, as shown in 3.

Figure 3 flexible business logic

The WEB service layer of the data center has three types of servers: IPv4, IPV6, and dual-stack. IPv4 WEB servers can only be used in traditional IPv4 application systems, and their backend APP servers are also IPv4; IPV6-only WEB servers can only access the IPV6 APP background. The dual-stack WEB servers support more flexible apps, either IPv4 or IPV6, applications that require data exchange can be implemented through dual-stack apps.

It is generally recommended that after the frontend network is upgraded to IPV6, the backend still supports the very mature v4 platform. After the IPV6 of the background app is mature and stable, the switch will be implemented, this will be of great benefit to system stability.

Thoughts on Dual-stack data center planning and deployment

The basic planning of the dual-stack data center can still adopt the traditional construction method (as shown in Figure 4). The structure, modularization and standardization are the basic elements of the data center construction. The difference is that the data center needs to separate the application systems in a large group of IPv4 and IPV6 applications to facilitate subsequent application expansion, dual-stack routing control, and mutual access between IPV6 and IPv4. For external access (such as Internet Services) provided by the data center, two egress ports need to be planned, namely IPv4 Internet egress and IPV6 Internet egress. Based on the consideration of simplified network O & M and stable operation, it is recommended that the two outlets be connected separately. We recommend that you provide a separate network module outlet for your partners' network connections to ensure security and manageability.

Figure 4 dual-stack data center planning

An IPv4 Application Group is an existing system and generally maintains the original operating environment. An IPV6 Application Group is a new application group. It may be a newly created business group, or it may be a business-driven cluster that enables IPv4 applications to be upgraded to IPV6.

When planning IPV6 applications, you can deploy the internal system structure according to the flexible Features Shown in 3. IPV6 business groups may have simple service systems, such as FTP, video, file sharing and other servers based on a single-layer server architecture; also may have a pure IPV6 application server group based on WEB-APP-DB multi-layer architecture; it is also possible that an application system group (APP-DB or IPv4-based) that only supports IPv6 ). During the transition from IPv4 to IPV6 for a long period of time, a variety of hybrid methods will exist in the data center for a long time.

To upgrade an IPv4 data center in v6 mode, you must first dual-stack the core of the data center, the core of the dual-stack architecture not only supports the existing IPv4 data center network, but also protects a large amount of investment, and also facilitates large-scale expansion of the new IPV6 business system. An independent, high-performance, scalable, and stable dual-stack core is the most critical link for the subsequent development of data center IPV6.

5 shows a simple dual-stack deployment structure of the data center server group. It adopts the dual-stack core that runs at the same time in IPv4/IPV6, and deploy an integrated dual-stack security control layer (dual-stack security is a simplified model, suitable for large-sized dual-stack data centers, in the construction of large and medium-sized or key business systems, you can also deploy an independent security control layer based on IPv4 and IPV6 applications to differentiate and simplify the operation and management of security policies, the IPv4 and IPV6 systems are distributed in different network modules.

For the deployment of application optimization functions such as server Load balancer and SSL offload, function components are generally combined with the business system and allocated to the corresponding network module, instead of Dual-stack operations, this can reduce the complexity of the operation and management of the dual-stack data center and make full use of the traditional mature application architecture.

Figure 5 dual-stack data center structure

Conclusion

The development of IPV6 is first manifested in the application of IPV6 in the data center. During the long-term transition from IPv4 to IPV6, the dual-stack data center will become the basic construction mode. in-depth exploration and continuous practice are the best way for new IT construction in the pre-IPV6 era to be effective and sustainable. Building an efficient, stable, and agile IPV6 data center infrastructure is an important topic for H3C's new generation data center R & D and repeated practices.