Enterprise routers are used to connect multiple logically separate networks. The so-called logical network represents a separate network or a subnet. When data is transferred from one subnet to another, it can be done through a router. In fact, enterprise routers mainly connect enterprise LANs and wide area networks (Internet, Internet); generally speaking, enterprise heterogeneous network interconnection and multiple subnet interconnection should be completed using enterprise routers.
An enterprise router is actually a computer because its hardware is similar to a computer; a router usually includes a processor (CPU); different types of memory--mainly used to store information; various ports--mainly used to connect peripheral devices or allow it to communicate with other computers; and the operating system-mainly provides various functions.
Enterprise router software is one of the complex software. Some routing software runs on embedded operating systems, some runs on UNIX operating systems, and some even have operating systems themselves to improve efficiency. Router software generally implements other functions such as routing protocol functions, table lookup and forwarding functions, and management and maintenance. Due to the huge scale of the Internet, the routing tables running in routers on the Internet are very huge, and may contain hundreds of thousands of routes. It is conceivable that the work of looking up table forwarding is very heavy. In high-end enterprise routers, these features are usually implemented by ASIC chip hardware.
The high complexity of enterprise routing software is reflected in high reliability, high availability and robustness. The functions of implementing routing software are not complicated. In free sharing software, we can even obtain the implementation source code of routing protocols and data forwarding. However, the difficulty lies in the need of the software to run efficiently and reliably for 365 days a year, 24 hours a day.
At present, commonly used enterprise routers generally have layer 3 switching functions, providing support capabilities such as speed, quality of service (QoS), multicasting, powerful VPN, traffic control, IPv6, multicast and MPLS, etc., to meet the security, stability, reliability and other requirements of enterprise users.
1. Classification of enterprise routers
There are many types of enterprise router products according to different classification standards. Common categories are as follows:
According to performance level, it is divided into high, medium and low routers.
Routers with a router throughput greater than 40Gbps are usually called high-end routers, routers with a back throughput between 25Gbps and 40Gbps are called mid-range routers, and those with a router with a router with a router with a back throughput of between 25Gbps are considered low-end routers. Of course, this is just a macro division standard, and the divisions of each manufacturer are not completely consistent. In fact, the division of router grades is not only based on throughput, but also has a comprehensive indicator. Taking Cisco, which has the largest market share, as an example, the 12000 series is a high-end enterprise router, and the 7500 series of routers are mid- and low-end enterprise routers.
Structurally divided into "modular router" and "non-modular router".
The modular structure can flexibly configure the router to meet the increasing business needs of the enterprise. Non-modular ones can only provide fixed ports. Usually, mid-to-high-end routers are modular structures, while low-end routers are non-modular structures.
From a functional division, routers can be divided into "backbone-level routers" and "enterprise-level routers".
Backbone-level routers are key devices for enterprise-level network interconnection, and their data throughput is large and very important. The basic performance requirements for backbone-level routers are high speed and high reliability. In order to obtain high reliability, network systems generally adopt traditional redundant technologies such as hot backup, dual power supply, dual data paths, etc., so that the reliability of backbone routers is generally not a problem.
Enterprise-level routers connect to many terminal systems, with more connection objects, but the system is relatively simple and the data traffic is small. The requirement for this type of router is to achieve as many endpoint interconnections as possible in a cheaper way, and also requires that it can support different service quality.
2. Functions of enterprise routers
Simply put, enterprise routers mainly have the following functions:
First, network interconnection, routers support various LAN and wide area network interfaces, mainly used to interconnect LAN and wide area networks, and realize communication between different networks;
Second, data processing provides functions including packet filtering, packet forwarding, priority, multiplexing, encryption, compression and firewall;
Third, network management, the router provides functions including configuration management, performance management, fault-tolerant management and traffic control.
In order to complete the "routing" function, the relevant data of various transmission paths is stored in the enterprise router - the routing table for use when routing selection. The routing table contains the subnet logo information, the number of online routers and the name of the next router. The routing table can be fixedly set by the system administrator, or dynamically modified by the system, can be automatically adjusted by the router, or controlled by the host. There are two names related to addresses involved in routers, namely: static routing table and dynamic routing table. The fixed routing table set by the system administrator in advance is called a static routing table. It is generally pre-set according to the network configuration when the system is installed, and it will not change with the future changes in the network structure. Dynamic routing table is a routing table that the router automatically adjusts according to the operation of the network system. Enterprise routers automatically learn and remember network operation according to the functions provided by the Routing Protocol, and automatically calculate the optimal path for data transmission when needed.
3. Characteristics of enterprise routers
One function of an enterprise router is to connect different networks, and the other function is to select the information transmission route. Choosing a smooth and fast shortcut can greatly improve communication speed, reduce the communication load of enterprise network systems, save network system resources, and improve network system smoothness, so that enterprise network systems can play a greater benefit.
Therefore, its advantage is that it is suitable for large-scale enterprise network connections, which can adopt complex network topology, load sharing and optimal paths, can better handle multimedia and have high security; save the bandwidth of the LAN, isolate unnecessary traffic, and reduce the burden on the host. The disadvantages of enterprise routers are also very obvious, that is, they do not support non-routing protocols, are complex installations, and are relatively high in price.
Article entry: csh Editor in charge: csh