Analyze smart switch products and precautions

Currently, many smart switches are equipped with the Voice Gateway module, which enables the Ethernet switch to fully provide the VoIP function. However, this function also has application conditions and requires network cables and telephone lines to be separately deployed on the client. The difference between a smart switch and a traditional switch is that it supports a dedicated "Blade" server with application functions, these include Protocol sessions, remote images, tape simulation, and Intranet file and data sharing.

From an architecture with additional processing capabilities for each port and highly integrated bandwidth between blade servers, to a relatively simple architecture where each server is equipped with a dedicated processor, the architecture of the memory and the input and output functions used for communication between ports. Intelligent switching has many different architectures. Different merchants use different names, such as "intelligent exchange", "application exchange", and "organization exchange", to make themselves stand out in the competition. Take Cisco's MDS9000 series as an example. There are blades that support applications such as Veritas Volume Manager and IBMSAN volume controller (SVC. These blades can coexist with other blades, including Fiber Channel ports and IP servers. Five basic procurement principles for smart switches:

Principle 1: Monitoring and Management of networks and devices

Management is the basis of intelligent exchange. Generally, the network management system includes five functional domains, including performance, configuration, failure, billing, and security, this is the most basic and commonly used function. With the expansion of the user's network scale and the increase of network applications, real-time monitoring and maintenance of network operation conditions become very necessary. The network management system and intelligent switching equipment must work closely together.

Currently, there are two common types of network management systems. One is a common network management platform, such as HPOpenView. It provides a third-party network management platform that supports the discovery and simple monitoring of all SNMP devices. However, because the devices of various manufacturers have a large number of self-developed private MIB (ManagementInformationBase) libraries, the general network management platform cannot identify and manage them. Therefore, if you want to monitor, manage, and configure various devices in detail, you must perform secondary development. In recent years, the devices of various vendors have been updated quickly, but the cooperation with third-party universal network management platforms has been very limited, making it difficult for the general network management platform to manage devices of multiple vendors in detail. The other is a network management platform developed by network equipment manufacturers, such as CiscoWORKS and shenzhoudigital LinkManager. It can perform in-depth and meticulous monitoring, configuration, and management on the devices of the manufacturer, it is highly practical and inexpensive. However, the problem is that such network management systems cannot be used to achieve unified management of devices across the network. Therefore, users often use multiple network management workstations to install different systems for separate management.

As users demand uniform network management for different devices, manufacturers are also considering more open ways to support network management, such as opening a private MIB library, the MIB library is written in full accordance with RFC to achieve interoperability between devices and network management systems of different vendors.

At present, the proportion of the Application Network Management System in large and medium-sized enterprise networks has been greatly increased. Therefore, when selecting a network, you cannot perform topology discovery, traffic monitoring, status monitoring, and other common network management functions, it also puts forward higher requirements for remote device configuration, user management, access control, and QoS monitoring. In addition, to save IP addresses and simplify management layers, different vendors use stack or cluster network management technologies to manage multiple devices as one logical device. Users can also pay attention to such products.

Principle 2: Classification and processing of data of different application types

Another important manifestation of intelligent exchange is to automatically classify different types of data in the network and provide different transmission policies to ensure smooth operation of key applications, that is, QoS ). Currently, common QoS technologies include IntServ (RSVP) and DiffServ.

The former uses the Resource Reservation method, that is, for each different application, the "End-to-End" dedicated channel is reserved on the network, to ensure that key applications enjoy dedicated bandwidth resources. Resource Reservation is a virtual leased line solution that ensures the transmission quality of key applications, but cannot achieve bandwidth sharing, which can easily lead to a waste of line resources, resource Reservation is only suitable for simple network topologies, such as point-to-point physical connections between routers. It is difficult to implement complicated and large enterprise networks, let alone man. Therefore, it is best for users to use a DiffServ smart switch to achieve "end-to-end" QoS. To achieve DiffServQoS, all related smart switches on the user's network must support the 802.1p priority function.

Principle 3: Support for multimedia transmission

Vswitches support more and more functions and protocols dedicated to multimedia transmission, the most typical of which is multicast technology. The Group Management Protocol IGMP has become a basic function required by smart switches. In addition to the RIP, OSPF, and other unicast routing protocols, layer-3 switches also support vmrp, PIMSM, DM, and other multicast routing protocols.

During multicast applications (such as video conferences), each smart switch can transmit group information throughout the network through the IGMP protocol, so that each switch can determine the members of each group, the multicast routing protocol can route multicast packets so that multicast packets can be transmitted smoothly over the network. Among them, DVMRP is equivalent to the RIP Protocol for unicast, suitable for small-scale network applications, while PIM is a protocol-Independent Multicast Routing Protocol, divided into intensive mode (DM) and Sparse Mode (SM. Dense mode is mainly applicable to scenarios with large network bandwidth and concentrated user distribution, such as the company's lan. Sparse Mode is mainly applicable to scenarios with small network bandwidth and sparse user distribution, for example, Wan or Internet.

Some smart switches also have a voice gateway module that enables the Ethernet switch to directly provide the VoIP function. However, such applications also need to separately deploy network cables and telephone lines on the client. If the client's VoIP gateway is used, you can transmit voice and data through a network cable. The two solutions are superior and inferior, and must be determined based on the actual situation.

Principle 4: User Classification and Access Control

User Classification, permission settings, and access control are also important functions of smart networks. Due to the refinement of enterprise management, different access permissions should be set for different network resources for different users. Access Permissions can be set at the workgroup level or user level. Access Control Based on VLAN and layer-3 switching is a workgroup-level access control. In addition to isolating broadcast and improving network performance, VLAN is used to isolate different working groups for easy and controllable mutual access. A layer-3 switch can implement cross-VLAN access. By using the access control list ACL, you can set the access permissions of devices with different VLANs or IP addresses for different network services.