Viewpoint: deeply analyzes the principle of the router system and structure

With the development of the global routing industry, you can have a deeper understanding of the router system and structure. With the increase of network traffic and the expansion of network scale, how to improve the scalability of router technology is one of the most critical problems to be solved by the next generation router system.

The most popular solution is the computer cluster system, which is similar to the large-scale computer cluster system. The architecture of the router system needs to be re-designed to allow multiple independent routers to communicate with each other through internal connections, instead of communication interface connection, a multi-cabinet multi-chasis) router system router cluster system). Without affecting performance, the switching capacity of the entire system is expanded linearly, increase the number of interfaces. This is an important trend of the next generation of core router products, and most other associated technologies such as high availability support are closely related to this structure.

Increasingly complex structures

Obviously, the structure of the vro system has changed greatly, from the number of processors and the connection mode, from a single-CPU router to a single-bus multi-processor router, next to the fully distributed multi-processor router, the T-bit router will be interconnected among multiple cabinets in the future. From the perspective of the switching structure, high-end routers mainly adopt the shared storage structure, the virtual output queuing structure (VOQ) based on the switching matrix, and the output queuing structure. In the T-bit router structure, multi-level switching structure interconnection, Cube Interconnection, and super Cube Interconnection are used to achieve large-capacity non-blocking switching. Therefore, the exchange structure and the entire router system will become more and more complex.

Full support for IPv6

In the next-generation Internet and next-generation networks, IPv6 is the basic network protocol. From the Protocol perspective, the transition from IPv4 to IPv6 is the biggest protocol change facing the router, only by fully providing IPv6 support for high-end routers can we ensure the promotion and maturity of this technology. To support IPv6, high-end routers need to have more complex structures in route table design, forwarding structure optimization, and other aspects. At the same time, A large number of IPv6 applications will aggravate the network bottleneck caused by the router system. In summary, the research and development of next-generation high-end routers focus on the development direction of many new network technologies. They are still one of the key topics in the network field.

High reliability

How to improve the reliability and stability of routers is a top concern for network users, especially operators. We hope that the networks built by the router system can support high-level services. Therefore, manufacturers are committed to providing 99.999% reliability for 5 devices with 9 stability, which means that the annual router Interruption Duration cannot exceed 5 minutes ). The development of high reliability protocols is one of the hot topics of protocol development in the past two years. Based on the extension Implementation of routing protocols, the reliability is improved by adding Fault Tolerance capabilities to standard protocols. You can also implement quick routing protection using protocols such as MPLS. You can also implement high reliability by implementing your own router system code and HA between the master and slave routing modules.

Vro interface changes in two ways:

Interface speed: High-Speed POS ports such as OC48 and OC192 are widely used in high-end routers. 10GE Ethernet has been widely used by high-end router manufacturers since its standard release. In the future, 10GE and OC192 POS compatible wan phy ports will be widely used in man. Interface Type: POS and Ethernet have become the most widely used interface types of high-end routers. Some manufacturers also use PRR ports to form protection links or use optical interfaces such as CWDM, forming the convergence of Optical Networks and IP networks.

Price and Performance

In addition to the superficial price factors, users will consider the life cycle and operation management cost of the router system. The operator often needs to change the router in three years. If the life cycle of the router can be extended to 5 ~ 7 years, will save a lot of cost. By the same principle, the benefits of products with high reliability through stable networks will far exceed their prices.

More services are supported.

With the support of the Everything Over IP and all network media and transmission mechanisms for various applications such as voice and video Over Everything, the middle-end routers on the edge of the operator's network gradually evolve into multi-service routers. This is manifested in the following two aspects: due to the adoption of network processors and dedicated integrated circuits, the work of some router systems far exceeds the "Collection" of services ". Nowadays, most edge router systems are more like an IP service switch, which can generate two-layer and three-layer VPNs and support value-added services such as firewall, Ethernet, and VoIP.

With the continuous and rapid development of broadband networks, the middle-end router system can provide QoS support for voice and video, and use MPLS to implement some ATM and frame relay functions. Therefore, these middle-end routers can be used to transfer services originally transmitted from ATM and frame relay to MPLS networks.

Enhanced security

Some people are always doing network damage. Nowadays, network attacks occur frequently, not only attacking computer terminals in the network, but also attacking the network's infrastructure routers and switches, the hidden risks of the network not only occur at the application layer, but also on the second and third layers of the network. As the backbone network edge and core router, if an attack causes downtime, the network service will be interrupted, causing heavy losses to users, especially telecom operators. At present, high-end edge routers are capable of self-protection and timely detection of network attacks. Integrates traffic management, IDS, IPS, firewalls, and other functions on high-end routers. In addition, some vendors such as Cisco use hardware to implement these security functions, the primary CPU of the vro system is responsible for data forwarding, and the network security detection is handled by the CPU in each hardware function module, such as IDS, IPS, and firewall, this will not affect the network traffic. If you use software to implement IDS, IPS, and firewall functions, the main CPU of the router must be separated to perform these security checks, which reduces the traffic of the entire network.

Internet traffic doubles every 12 months, while vro capacity doubles every 18 months. Although the increase in memory capacity can be consistent with Moore's Law, the increase in memory access speed is far from reaching this indicator, because high-speed memory is very expensive. Therefore, although the performance of the router system has been improving, the speed of improvement lags behind the speed of network development.