The connection and difference between router / switch and Hub Hub (HUB) Frame switching Frame switching is currently the most widely used LAN switching technology. It provides a parallel transmission mechanism by micro-segmenting traditional transmission media to reduce collision domains and obtain high bandwidth. In general, the implementation technology of each company's products is different, but there are two main ways of processing network frames: true exchange and storage and forwarding. The cell exchange ATM technology represents a good medicine for many problems in network and communication. ATM uses a fixed length of 53 bytes for cell exchange. Due to the fixed length, it is easy to implement in hardware. ATM uses a dedicated non-differential connection and runs in parallel. Multiple nodes can be established at the same time through a switch, but it does not affect the communication capabilities between each node. ATM also allows communication capabilities between the source node and the target node. ATM uses statistical time division circuits for multiplexing. Therefore, the channel utilization rate can be greatly improved. The bandwidth of ATM can reach 25M, 155M, 622M and even several GB of transfer capability. NetFlow technology is the same as CEF, NetFlow is also a new technology that is gradually improving. The main function of NetFlow is that it can provide service providers and enterprises with information on network capacity planning, trend analysis, and data priority. This technology can also be used for IP-based billing applications and service level assurance (SLA) verification services. On the basis of NetFlow, Cisco also proposed NetFlow policy routing (NPR) technology. This technology based on Cisco IOS service provides the functions of traffic planning and IP pre-classification, and provides an efficient and high-performance NetFlow mechanism for policy routing. Since NPR also supports the CEF architecture, it can be used on distributed platforms. The router is actually a computer with complex technology and strong processing power. It has hardware such as CPU, RAM, and ROM. Flash is called flash memory and stores system image files (internet operating systems, such as Cisco IOS). The operating speed is faster than ordinary memory, and the price is also expensive; NVRAM (NonvolaTIle RAM) stores the router startup configuration file (ConfiguraTIon file or starup-config), which is equivalent to Autoexec in the PC. bat file; routers generally have LAN interface and WAN interface except Console port and Auxiliary port: LAN interface is the same as Switch port, and there are differences in speed and interface type (RJ45, ST / SC, OC-3 / STM-1, 155Mb / s, 100Mb / s AnyLAN, etc.); WAN interfaces include synchronous serial port and asynchronous serial port, EI, TI, T3, etc. Although routers belong to the category of LAN products, it is accurate to say that routers should be the main node equipment of the Internet. At present, routers as Internet "traffic police" have been widely used in all walks of life, and various grades of products have increasingly become the main force for the realization of various internal connections of backbone networks, interconnection between backbone networks, and interconnection between backbone networks and the Internet. The router determines the data forwarding through routing, and the forwarding strategy is called routing (rouTIng), which is the origin of the router name. As a hub for interconnection between different networks, the router system constitutes the main body of the Internet based on TCP / IP. It can also be said that the router constitutes the skeleton of the Internet. Its processing speed is one of the main bottlenecks of network communication, and its reliability directly affects the quality of network interconnection. Therefore, in the campus network, regional network and the entire Internet research field, router technology has always been at the core position. Router products have become the most technical and important network equipment. According to the application requirements, the overall size of the product is determined to be 19 inches, which is mostly rack-mounted. The desktop or SOHO routers are similar in shape to the external MODEM, but have a larger shape. Generally speaking, if the network equipment in the LAN needs centralized management, it is best to choose a 19-inch wide rack router, such as Cisco2509, Huawei 2501 (configuration is the same as Cisco2501); if there is no such requirement, desktop routers such as Intel The 8100 and Cisco's 1600 series have higher cost performance. Determine the basic performance indicators of the product according to the direction of purchase. The router works as a "black box" in the network equipment in the background. When choosing a router product, you should consider it from a technical perspective, such as scalability, routing protocol interoperability, wide-area data service support, internal ATM support, and SAN integration capabilities. In addition, the selection of routers should also follow the principles of standardization, technical simplicity, environmental adaptability, manageability, and fault tolerance and redundancy. Especially for high-end routers, more consideration should be given to whether and how to adapt the backbone network to the high reliability of the network, high scalability of the interface, and high-performance requirements for route lookup and data forwarding. The "three high" features of high reliability, high scalability, and high performance are the key differences between high-end routers and mid-range and low-end routers. When examining router products in terms of technical performance, it is generally necessary to investigate the router's capacity, how many packets per second can be processed, whether it can be clustered, and other performance issues. Also pay attention to whether the router can provide value-added services and other various services, such as VPN SLA, QoS, MPLS, Diffserv and multicast communication. In addition, whether the router can support hot plugging is also an important performance index that router products should investigate. Examining the network scalability of routers is also an important point of examining router products. With the gradual increase of computer network applications, the existing network scale may not be able to meet the actual needs, which will result in the requirement to expand the network scale, so the expansion capability is a network must be considered in the design and construction process. The size of the expansion capability mainly depends on the number of expansion slots or expansion ports supported by the router. To consider the possible network upgrade in the near future, so when selecting equipment, we must focus on the network expansion capabilities of the router. Investigating the network management system of routers Because routers have very critical and important control tasks, as the network scale continues to increase, the burden of network maintenance and management becomes heavier, so the network management system at the router level is particularly important . When you choose a router, you must pay attention to whether the monitoring and configuration capabilities of the network system are strong, and whether the device can provide statistical information and diagnostic functions for deep fault detection. Due consideration is given to the brand of router products. Due to the high technical content and high price of routers, the more high-end products, the more attention should be paid to the brand of the product. The router products of famous brands with many years of research and development and sales history abroad are more guaranteed. Generally trustworthy. We have experience and skill to support customers to tooling for their required Waterproof Connectors, like IP68 series,Micro Fit Connectors. Etop wire assemblies for various industries have been highly recognized by all the customers and widely used for automobiles, electrical and mechanical, medical industry and electrical equipemnts, etc. Products like, Wire Harness for car audio, power seat, rear-view mirror, POS ATM, Diesel valve Cover gasket fit, elevator, game machine, medical equipment, computer, etc. JST Connector,Molex Connector, Multi-Contact Connector, Micro Fit Connectors ETOP WIREHARNESS LIMITED , https://www.etopwireharness.com
Hub (HUB) is one of the important parts in local area network LAN, it is the connection point of network connection. The hub has multiple household ports to connect peripheral devices such as computers and servers. An Ethernet data packet is sent from a station to the hub, and then it is broadcast to all other ports in the hub, so the hub-based network is still a shared medium LAN. Each port of the smart hub can be configured, monitored, connected, or interpreted by the network operator from the hub management console. Hub management also includes collecting information about various network parameters, such as the number of packets passing through the hub and each of its ports, what type of packets they are, whether the packets contain errors, and how many collisions have occurred.
There are currently three hub configurations:
Standalone hub Standalone hub is a single box-type product with many ports. The independent hubs either use a 10Base-5 coaxial cable to connect them together, or connect them with twisted pairs between the independent ports on each hub. Standalone hubs are usually the cheapest hubs and are often unmanaged. They are best suited for small independent work groups, departments or offices.
2. Modular hubs Modular hubs are very popular in the network because they are easy to expand and have management options. The modular hub is equipped with a rack or a card box, with multiple card slots, each slot can hold a communication card. Each card functions as a stand-alone hub. When the communication cards are placed in the card slots in the rack, they are connected to the communication backplane, so that the ports of the two communication cards on the backplane can easily communicate. The size of the modular hub can range from 4 to 14 slots, so the network can be easily expanded.
3. Stacking hub The third type of hub is a stacking hub. Except that multiple hubs can be "stacked" or connected together with short cables, their appearance and functions are similar to stand-alone hubs. When they are connected together, they act like a modular hub and can be managed as a unit. A manageable hub used in the stack provides management of other hubs in the stack. These hubs are ideal when an organization wants to start with a small amount of investment and meet future growth.
3. Switch
The switch is a network device based on MAC address identification and capable of encapsulating and forwarding data packets. The switch can "learn" the MAC address and store it in the internal address table. By establishing a temporary exchange path between the originator and the target receiver of the data frame, the data frame directly reaches the destination address from the source address. The emergence of switches has led to an increase in bandwidth.
The main functions of the switch include physical addressing, network topology, error checking, frame sequence, and flow control. At present, the switch also has some new functions, such as support for VLAN (Virtual Local Area Network), support for link aggregation, and some even have a firewall function.
1. The difference between a switch and a hub
The biggest difference between Switch and Hub is that the switch processes port data in exchange rather than in a shared manner, thereby effectively increasing the system bandwidth. Its working principle is completely different from the shared Hub. It can receive and temporarily store the packet sent, and then send it to another port. If Hub is regarded as a built-in Ethernet bus, Switch can be regarded as a multi-bus-switch matrix interconnection. Specifically, the Switch hangs each port on a high-bandwidth backplane bus (CoreBus) (at least an order of magnitude higher than the port bandwidth). The backplane bus is connected to a switching engine (Switch Engining) and is lost by the port. The incoming encapsulated data packets enter the switching engine via the backplane bus, and then reach the destination port.
2. Data exchange method of the switch
Cut through: After the encapsulated data packet enters the switching engine, it is dropped on the backplane bus within a specified time and then sent to the destination port. This switching method has a fast switching speed, but it is prone to packet loss. Then there is a buffer, which is forwarded by the switching engine to the backplane bus. This switching method overcomes the packet loss phenomenon, but reduces the switching speed; Fragment Free: a solution between the above two.
3. Three kinds of switching technology port switching port switching technology first appeared in the slot-type hub, the backplane of this type of hub is usually divided into multiple Ethernet segments, without the use of bridges or routers, the network is not connected of. After the Ethernet main module is inserted, it is usually allocated to a network segment of a backplane. Port switching is used to distribute and balance the ports of the Ethernet module among multiple network segments on the back bench. According to the degree of support, the port can also be subdivided into: module switching, port group switching and port-level switching.
The switching speed of the former method is very fast, but it lacks more advanced control of network frames, lacks intelligence and security, and cannot support the switching of ports with different rates. Therefore, manufacturers focus on the latter technology.
4. Multi-layer switching technology Multi-layer switching (also known as Layer 3 switching technology, or IP switching technology) is proposed relative to the traditional switching concept. As we all know, the traditional switching technology operates at the second layer of the OSI network standard model-the data link layer, while the multi-layer switching technology implements high-speed data packet forwarding at the third layer of the network model. Simply put, the multi-layer switching technology is: Layer 2 switching technology + Layer 3 forwarding technology.
The emergence of multi-layer switching technology solves the situation that after the network segmentation in the LAN is divided, the subnets in the network segment must rely on routers for management, and solves the network bottleneck problem caused by the low speed and complexity of traditional routers. Of course, the multi-layer switching technology is not a simple stack of network switches and routers, but an organic combination of the two to form an integrated and complete solution.
5. Two new technologies in the switch
With the gradual popularization of CEF technology, the data transmission mode of Internet has changed a lot. The data shuttles between different networks more frequently, which makes a large number of short-lived IP packets in the network, and from the perspective of topology, their destination addresses are often very different. CEF is produced under such a background, mainly used to optimize the characteristics of network data transmission.
CEF is a completely topology-based architecture. The previous switching system used the first packet in the data stream to create a buffer for the IP destination address, and then all subsequent packets sent data to this address; and CEF used all valid routing information to create an optimized IP Forward Information Base (FIB), using FIB, even for the data initialized for the first packet, the switch or router can still quickly find an optimal path for network transmission. CEF has actually become an efficient Internet switching architecture.
The working principle of NetFlow is: NetFlow first records the data of initializing IP packets, such as IP protocol type, type of service (ToS), interface identification, etc. Then, in order to more effectively match and count the data, NetFlow allows the subsequent data to Transmit in the same data stream, at the same time, use their respective corresponding services, such as security filtering, QoS strategy, traffic planning, etc. Real-time data is stored in NetFlow's cache and can be retrieved by reading the operation instructions.
Four. Router (Router)
When two different types of networks are connected to each other, a router must be used. For example, LAN2 is a Toking Ring and LAN1 is Ethernet. To connect these two networks, a router is required, as shown in the following figure.
The router works at the third layer (network layer) of the OSI model. Therefore, it is related to high-level protocols; and because it is a layer higher than the bridge, it is more intelligent. It not only has transmission capabilities, but also has path selection capabilities. When a link fails, the router will choose a good link to complete the communication. In addition, the router has the ability to select the shortest path.
Routers are more complex, and their speed of transmitting information is slower than that of bridges. They are generally suitable for large, complex network connections.
It works at the network layer of the OSI reference model, so it accesses the other party's network address, and can exchange and route data frames at the network layer.
1. The function of routers The so-called routing refers to the activities of moving information from the source to the destination through interconnected networks. A router is such a network device that connects multiple networks or network segments. Data information between different networks or network segments is "translated" so that they can "read" each other's data to form a larger network. A router is also called a sizing device. It can be said to be a key device for interconnection at the network layer. It usually has two typical functions, namely, data channel function and control function. Data channel functions include forwarding decision, forwarding, and output data link scheduling, etc., which are generally completed by hardware; control functions are generally implemented by software, including information exchange with neighboring routers, system configuration, and system management. Its application is more complicated than the bridge and also has more flexibility. In the past, routers were mostly used for wide area networks. In recent years, due to the great improvement in router performance, the price has dropped to close to the bridge. Therefore, routers are increasingly used in LAN interconnection.
2. The difference between routing and switching Routing and switching are two concepts that common users can easily confuse. Generally speaking, in the routing process, information will pass through at least one or more intermediate nodes, so people usually compare routing and switching, mainly because in the eyes of ordinary users, the functions implemented by the two are exactly the same . In fact, the main difference between routing and switching is that switching occurs at the second layer (data link layer) of the OSI reference model, while routing occurs at the third layer, the network layer. This difference determines that routing and switching need to use different control information in the process of moving information, so the way in which the two implement their respective functions is different.
3. Types of routers Routers can be seen everywhere on various levels of the Internet, and routers can usually be divided into access routers, enterprise routers, and backbone routers. Access routers connect small business customers in homes or ISPs, so that homes and small businesses can connect to an Internet service provider; enterprise or campus-level routers connect many terminal systems, and the main goal is to achieve as much as possible by the cheapest method possible. Multiple endpoint interconnections, and further requirements to support different qualities of service. The requirements for it are not only the number of ports and the price, but also the simple and convenient configuration, and the provision of QoS; backbone-level routers implement the interconnection of enterprise-level networks. Its requirements are mainly speed and reliability, while the cost price is in a secondary position.
4. The main points of the router purchase to determine the product type and grade according to the application environment. Because of the different application environments, the actual usage of users is also different, so the router is divided into access level, enterprise level or backbone level, respectively corresponding to low, medium and high-end products . Generally speaking, low-end access-level routers are mainly suitable for the lowest-level applications in the hierarchical system, or the applications of small and medium-sized enterprises. The products are mostly fixed-configuration or modular routers. The specific choice should be based on your own needs. Decided that one of the main factors to consider is the number of ports, and also depends on the packet switching capability. Mid-range enterprise routers are mainly suitable for large and medium-sized enterprises and Internet service providers, or mid-level systems in hierarchical systems, such as the application of city-level outlets. The principle of product selection is also to consider port support capabilities and packet switching capabilities. High-end routers are mainly used in core and backbone networks, and are generally products that provide Gigabit capabilities. The port density is extremely high. When choosing this type of router, the performance factor is the most important.
Investigating the control software of the router Many users know that the control software of the router is a key link for the router to function. From software installation, automatic parameter settings, to software version upgrades are essential. Therefore, when choosing a router product, it is necessary to pay attention to the pros and cons of the router's control software itself. It is best to choose a product with convenient software installation, parameter setting and debugging, and powerful functions.
Supplement: From the ISO seven-layer reference model, the diversity hub works at the physical layer (only for line aggregation)
The switch works at the data link layer (having a hub function and forwarding data at high speed per port)
Router works at the network layer (select path, forward data packets)