Five basic principles for purchasing intelligent switches

Principle I:

Monitoring and management of network and equipment

Management is the basis of intelligent exchange, the common sense of network management system, including performance, configuration, fault, billing and security, 5 functional domains, which is the most basic and most commonly used functions. With the expansion of user network and the increase of network application, real-time monitoring and maintenance of network operation becomes very necessary, which requires the close cooperation between network management system and intelligent switching equipment.

At present, the common network management system has two types, one is the common network management platform, such as HP OpenView, can provide a third party network management platform, support to all SNMP devices discovery and simple monitoring. However, due to the large number of proprietary MIB (Management information Base) libraries developed by each manufacturer, the common network management platform cannot identify and manage them. Therefore, if you want to achieve detailed monitoring, management, and configuration of various devices, you must develop two times. In recent years, the manufacturers of equipment update quickly, and the third party with the common network management platform is very limited, making the common network management platform is difficult to detail the multiple vendors of the equipment to manage.

Another type of network equipment manufacturers to develop their own management platform, such as Cisco Works, Shenzhou Digital Linkmanager, and so on, can be the manufacturer's equipment in-depth and meticulous monitoring, configuration and management, more practical and cheaper prices. However, the problem is that this type of network management system can not be used to achieve the unified administration of the whole network equipment, so users often use a number of network management workstations installed different systems, respectively.

As users of different devices to unified network management needs increasingly urgent, manufacturers are also considering a more open way to achieve the support of network management, such as open private MIB, or even completely in accordance with the RFC to write MIB Library, in order to achieve the interoperability between the equipment and network management systems of different vendors.

At present, in large and medium enterprise network, the proportion of application network management system has been greatly improved. Therefore, users can not be satisfied in the selection of topology discovery, flow monitoring, state monitoring and other general network management functions, but also for the equipment remote configuration, user management, access control and even QoS monitoring to put forward higher requirements.

In addition, in order to save IP address and simplify the management level, different vendors use the technology of stacking or cluster management to manage the multiple equipment as a logical device. Users can also focus on this type of product.

Principle Two:

Classification and processing of data of different application types

Another important embodiment of intelligent switching is the automatic categorization of different types of data in the network, and the provision of different transport strategies to ensure the smooth operation of critical applications, which is commonly called quality of Service (QoS).

The most common QoS technologies currently available are IntServ (RSVP) and DiffServ two ways.

The former uses the way of resource reservation, that is, for each kind of application, the "End-to-end" dedicated channel is reserved on the network to ensure that the key application can enjoy the fixed bandwidth resources alone. The way resources are reserved belongs to the solution of the virtual private line, can ensure the quality of key applications, but can not achieve the sharing of bandwidth, easy to cause the waste of line resources; In addition, resource reservation is only suitable for simpler network topology, such as point-to-point connection between routers, for complex and large enterprise network, it is difficult to implement, Not to mention the metropolitan area network.

Therefore, it is best for users to adopt DiffServ switches to achieve End-to-end QoS. It should be noted that for the implementation of DiffServ QoS, all relevant switches on the user's network are required to support the 802.1P priority feature.

Principle Three:

Support for multimedia transmissions

The switch supports more and more of the functions and protocols dedicated to multimedia transmission, among which the most typical is multicast technology.

Group Management Protocol IGMP has become a necessary basic function of intelligent switches. But for the three-layer switch, in addition to rip, OSPF and other unicast routing protocols, also began to support DVMRP, PIM SM/DM Multicast routing protocol.

In the event of multicast applications (such as video conferencing, etc.), each switch can pass the packet information in the whole network through the IGMP protocol, make each switch determine the members of each group, and multicast routing protocol can route the multicast packet, and make the multicast packets transmit smoothly on the network. Among them, DVMRP is equivalent to the RIP protocol of unicast, which is suitable for small-scale network applications, while PIM is a protocol-independent multicast routing protocol, which is divided into dense mode (DM) and sparse mode (SM). Dense mode is mainly applicable to the network bandwidth, user distribution more concentrated occasions, such as the company's local area network; Sparse mode is mainly used in the case of small network bandwidth and sparse user distribution, such as WAN or Internet.

Some switches also configured a voice gateway module, so that the Ethernet switch directly with the VoIP function, but such applications also need to be in the client separately cloth network cable and telephone line; If the client's VoIP gateway, the voice and data transmission can be realized through a network cable. The two schemes are superior or inferior, and they should be judged on the basis of the actual situation.