Discuss the principle of setting up the mercury Router

Source: Internet
Author: User

Internet users have their own choices regarding the setting of the mercury router. The following describes the basic concepts of the router. I hope you can give it a try and give more friends a valuable reference. Everyone should know that the price of routers is very expensive.

Mercury router settings: What is a vro

Routing refers to the activity of moving information from the source location to the target location through a interconnected network. Generally, information passes through at least one or more intermediate nodes during routing. In general, people will compare routing and switching, mainly because the functions of the two are the same in the eyes of common users.

In fact, the main difference between routing and switching is that switching occurs at the Layer 2 data link layer of the OSI reference model), while routing occurs at the Layer 3, that is, the network layer. This difference determines that different control information needs to be used in the process of routing and exchange of mobile information. Therefore, the two methods to implement their respective functions are different.

As early as 40 years ago, there have been discussions on the routing technology, but it was not until 1980s that the routing technology was gradually commercialized. The reason why the routing technology was not widely used at the beginning was that the network structure before 1980s was very simple and the routing technology was useless. It has not been until the last decade that large-scale interconnected networks have become popular, providing a good foundation and platform for the development of routing technology.

Vro is the main node device on the Internet. The router determines data forwarding through routing. The forwarding policy is called ROUTING selection ROUTING), which is also the origin of the ROUTER name ROUTER, the forwarder ). As a hub connecting different networks, the router system forms the main context of the TCP/IP-based INTERNET. It can also be said that the router forms the backbone of the INTERNET.

The processing speed is one of the major bottlenecks of network communication. Its Reliability directly affects the quality of network interconnection. Therefore, in the field of campus network, Regional Network, and even INTERNET research, router technology is always at the core position, and its development history and direction have become a microcosm of INTERNET research.

As China's network infrastructure and information construction are in the ascendant, this paper explores the role, position, and development direction of routers in the interconnection network, it is of great significance to clarify the plausible concepts of vrouters and network interconnection in the network market.

Mercury router settings: Role of vro

One role of a router is to connect different networks, and the other is to select the information transmission line. Selecting smooth and fast routes can greatly improve the communication speed, reduce the communication load of the network system, save network system resources, and improve the network system accessibility rate, so that the network system can exert greater benefits.

From the perspective of filtering network traffic, the role of a router is very similar to that of a switch and a bridge. However, unlike switches that work on the physical layer and divide network segments physically, vrouters use specialized software protocols to logically divide the entire network. For example, a router that supports the IP protocol can divide the network into multiple sub-network segments. Only network traffic directed to a Special IP Address can pass through the router.

For each received packet, the router recalculates its verification value and writes it to a new physical address. Therefore, the speed of data forwarding and filtering by vro is usually slower than that of A vswitch that only views the physical address of a data packet. However, vrouters can improve the overall efficiency of networks with complex structures. Another obvious advantage of a vro is that it can automatically filter network broadcasts. In general, the installation process of adding a vro to a network is much more complex than that of a plug-and-play vswitch.

Generally, a vro should be used to connect a heterogeneous network to multiple subnets. The main task of a router is to find an optimal transmission path for each data frame passing through the router and transmit the data to the destination site effectively. It can be seen that the routing algorithm is the key to selecting the optimal path.

To achieve this, the route table routing table is stored in the router for ROUTING selection. The path table contains the subnet flag information, the number of online routers, and the name of the next router. The path table can be set by the system administrator or dynamically modified by the system. It can be automatically adjusted by the router or controlled by the host.

Mercury router settings: static path table

The system administrator sets a fixed path table in advance to call it a STATIC path table. Generally, it is set in advance according to the network configuration during system installation, it will not change as the network structure changes in the future.

Dynamic Path table

DYNAMIC) the path table is automatically adjusted by the router according to the running status of the network system. The router selects the routing protocol) to automatically learn and remember the network running status, and automatically calculate the optimal path for data transmission as needed.

Vro Structure

From the perspective of architecture, routers can be divided into the first generation single-CPU Single-structure router, the second generation single-bus master-slave CPU Structure router, and the third generation single-bus symmetric multi-CPU Structure router; the fourth generation multi-bus multi-CPU Structure router, the fifth generation shared-memory structure router, the sixth generation cross-Switch Architecture router, and the vro Based on the cluster system.

Mercury router settings: Router Composition

A vro has four elements: the input port, the output port, the switch, and the route processor. The input port is the entrance of the physical link and input package. A port is usually provided by a line card. A line card generally supports 4, 8, or 16 ports. An input port has many functions. The first function is to encapsulate and deencapsulate the data link layer. The second function is to find the destination address of the input package in the forwarding table to determine that the destination port is called a route query). Routing Query can be implemented using common hardware, alternatively, you can embed a microprocessor into each line card.

Third, in order to provide QOS service quality), the port should divide the received packet into several predefined service levels. Fourth, ports may need to run network-level protocols such as the SLIP Serial Line Internet protocol and the PPP Point-to-Point Protocol) or the PPTP Point-to-Point Tunneling Protocol. Once the route query is complete, you must use the switch to send the packet to its output port. If a router is added to a queue at the input end, several inputs share the same switch. In this way, the last function of the input port is to participate in the arbitration agreement for public resources such as the switch.

The switch can be implemented using different technologies. So far, the most widely used switch technology is bus, cross switch and shared storage. The simplest switch uses a bus to connect all input and output ports. The disadvantage of the bus switch is that its switching capacity is limited by the capacity of the bus and the additional overhead for shared bus arbitration. The crossover switch provides multiple data paths through the switch. A crossover switch with N × N intersections can be considered to have 2N buses. If a crossover is closed, the data on the input bus is available on the output bus; otherwise, the data is unavailable.

The scheduler controls the closing and opening of intersections. Therefore, the scheduler limits the switching speed. In the shared Storage Router, the incoming package is stored in the shared storage, and only the packet pointer is exchanged, which improves the switching capacity. However, the switch speed is limited by the storage device access speed. Although the storage capacity can double every 18 months, the storage access time is reduced by only 5% each year, which is an inherent limitation of the shared storage switch.

The output port stores packets before the packets are sent to the output link. complex scheduling algorithms can be implemented to support priorities and other requirements. Like the input port, the output port must also support encapsulation and encapsulation of the data link layer, as well as many advanced protocols. The Route Processor calculates the forwarding table to implement the routing protocol and runs the software that configures and manages the router. At the same time, the mercury router also handles packets whose destination addresses are not in the line card forwarding table.

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