Vro Technology Revolution

As the core device, the router is in a crucial position on the IP network. With the popularization of Internet applications and the rapid increase of network bandwidth, the user's requirement for service quality is improved, and the router technology is also facing new changes. Exchange Routing Technology is a hot topic in this field. It not only solves communication traffic problems, but also has higher network control and management capabilities.

80/20 rule Evolution

The disadvantages of software-based routers are well known. Software-based routers are sufficient when the network traffic is mainly carried out within the Working Group. Because the main network traffic is not cross-route boundary, the slow forwarding performance of the router will not affect the implementation of the routing protocol too much. This is the so-called 80/20 rule, that is, 80% of the network traffic occurs in the Working Group, and 20% of the network traffic is carried out across the Working Group.

However, the network environment has changed dramatically, as Web applications have experienced explosive growth, network traffic distribution models have become unpredictable, and the number of users has increased exponentially. However, controlling network traffic is still an important network requirement. People can no longer accept the performance defects of software-based routers. Now, the 80/20 rule has been converted to 20/80.

During a heated discussion in the industry, the performance occupies a central position. A software-based Router forwards data packets at a rate of 100,000 packets per second, while a switched router forwards data packets to tens of millions of packets per second. This kind of performance improvement is achieved by changing the architecture: Traditional routers use software running on the microprocessor to forward data packets, while switched routers use hardware, such as dedicated Integrated Circuits (ASICs ).

Although the basics of packet forwarding technology have changed, the tasks to be completed are the same: Check the incoming data packet and compare its target address with the project in the route table, and then send it from the correct interface. In this process, data packets also accept some additional processing tasks.

Improvement of network control capability

Traditional routers cannot guarantee both performance and control functions. The control function is provided by a series of rules, for example, priority, access denied, or accounting data. When data packets enter the vro, these rules also apply to data packets. In a software-based Router, these rules are stored in a software database, and each data packet must be checked when it passes. This is the root cause of the problem: the microprocessor processing the routing function must also query the database. At this time, data packets are not sent, so the router's forwarding capability is low.

The new-generation exchange router will not encounter this problem, because the query and control functions are implemented in hardware. The key to combining the performance and control functions of a switched router is how much the ASIC can read per packet.

The more information ASIC can collect about the traffic of each data packet, the finer the control level that can act on the data packet stream.

Each Client/Server conversation generates a packet between the client and the server. Data Streams composed of these data packets can be identified on the second, third, or fourth layers of OSI. Each layer provides more detailed information about the stream. The most basic task of managing a network is to control the network traffic. On Layer 3, each data packet in the data stream is identified by the MAC addresses of the source site and destination site. On Layer 3, data streams are identified by source and destination network addresses. The ability to control data streams is limited to source/destination address pairs. For example, a vswitch vro called a Layer 3 switch is now available on the market. If a client is using multiple applications on the same server at the same time, Layer 2 information will not provide a detailed description of each application stream, in this way, different control rules cannot be implemented for each data stream one by one.

Traditional routers are capable of reading layer-4 header information. In fact, most of the advanced control features of traditional routers are implemented at Layer 4th. For example, in a software-based Router, Layer 4 information is used to establish a security filter, which is an important component in the process of controlling network traffic. However, for software-based routers, for the reasons described above, in-depth reading of data packets will greatly sacrifice performance. Indeed, among many software-based routers, performance can be reduced by up to 70% when security filters are enabled.

Combining the port number information of the 4th-layer header with the source/target information of the 3rd-layer header can achieve real precise control. The conversation flow of a specific application can be controlled between the client and the server. If the exchange router is fully functional, all this work can be done at line speed. By reading the layer-7 header information, the layer-2 switch can be divided into applications in the time zone of Route decision-making. Applications can be assigned different forwarding rules to ensure different service quality, or use security filters to provide application-layer control over the network.

Enter the trunk IP Network

Smart exchange routers can be used in large enterprise IP networks or operation service provider IP networks. These networks often run thousands of applications, with millions of data streams per second passing through the trunk switch device. In this environment, it is necessary to provide continuous network access unrelated to geographical locations. Smart exchange routers can meet the requirements of large network trunk devices and have great advantages in terms of price, performance, routing capability, and route table storage capacity. In addition, the smart switching router implements all the routing functions of the IP/IPX protocol, provides high interconnection capabilities with existing devices, and provides intuitive network management software. All this makes it an ideal solution to manage and control trunk links using smart exchange routers in large networks.

At present, mature exchange-type router products have emerged in the market, and their functions have been improved. For example, Cabletron's smart exchange router product provides more functions than traditional routers and layer-3 switches, it provides a standard solution for Layer 2, Layer 3, and Layer 4 switching at gigabit rates per second on all ports. The high-speed dedicated ASIC chip performs packet forwarding by searching the second, third, and fourth layer headers of data packets. In addition to the second and third-layer switching functions, Cabletron's intelligent exchange-type router SSR can realize bandwidth allocation by exchanging data packets on the fourth layer, fault Diagnosis and access control for TCP/IP application data streams. It provides detailed traffic statistics and accounting information, application layer QoS policies, and access control capabilities.

Article entry: csh responsible editor: csh