Router Working Principles

With the development of the communication industry, the routing application is also more extensive, and many people may not understand the working principle of the router. Here we will give you a detailed introduction. A router is a device that forwards data between subnets at the IP protocol network layer. The working principle of the router can be divided into control plane and data channel. On the control plane, the routing protocol can be of different types. The router works by exchanging the network topology information through the routing protocol, and dynamically generates a route table based on the topology.

On the data channel, after receiving an IP packet from the input line, the forwarding engine analyzes and modifies the packet header, uses the forwarding table to find the output port, and switches the data to the output line. The forwarding table is generated based on the route table. Its table items have a direct correspondence with the route table items. However, the forwarding table format is different from that of the routing table, which is more suitable for fast search. The forwarding process includes line input, packet header analysis, data storage, packet header modification, and line output. The routing protocol dynamically generates a route table based on the network topology. The IP Protocol divides the entire network into management areas. These management areas are called autonomous regions, and the autonomous domain area codes are centrally managed across the network. In this way, the routing protocol can be divided into intra-domain and Inter-Domain protocols. Intra-domain routing protocols, such as OSPF and IS-IS, represent the link status of the network topology in the inter-vro switching management domain, and export the route table according to the link status. Data exchange between adjacent nodes of the Inter-Domain Routing Protocol. The multicast mode cannot be used, but only the specified point-to-point connection can be used.

Router Architecture

The control plane of the router runs in the general-purpose CPU system and remains unchanged for many years. In the High Availability design, master-slave backup can be performed using the dual-master to ensure the reliability of the control plane. The data tunnel of the router adopts different implementation technologies to adapt to different line speeds and different system capacities. The router architecture is differentiated Based on the implementation mechanism of the data channel forwarding engine. In short, it can be divided into a software forwarding router and a hardware forwarding router. The software forwarding router uses the CPU software technology to implement data forwarding. Based on the number of CPUs used, it is further divided into single-CPU centralized and multi-CPU distributed. A hardware forwarding router uses network processor hardware technology to forward data. Based on the number of network processors used and the location of the network processor in the device, further subdivided into single-network processor centralized, multi-network processor load sharing parallel type and center switching distributed.

Router Security Settings

It is usually easier for hackers to launch attacks by exploiting vro vulnerabilities. Vro attacks waste CPU cycles, mislead information traffic, and paralyze the network. A good router uses a good security mechanism to protect itself, but this is far from enough. To protect the security of a router, the network administrator must take appropriate security measures when configuring and managing the working principle of the router.

1. Block Security Vulnerabilities

Limiting system physical access is one of the most effective ways to ensure vro security. One way to restrict physical access to the system is to configure console and terminal sessions to automatically exit the system after a short period of idle time. It is also important to avoid connecting the modem to the secondary port that works on the router. Once physical access to the vro is restricted, you must ensure that the security patch for the working principle of the vro is up-to-date. Vulnerabilities are often disclosed before the supplier releases the patch. This allows hackers to exploit the affected system before the supplier releases the patch, which requires the user's attention.

Ii. Preventing identity crisis

Hackers often use weak passwords or default passwords for attacks. This vulnerability can be prevented by using a password extension and a password validity period of 30 to 60 days. In addition, once an important IT Employee Resign, the user should change the password immediately. The user should enable the password encryption function on the working principle of the router, so that even if the hacker can browse the system configuration file, he still needs to decrypt the ciphertext password. Implement reasonable verification control so that the router can transmit certificates securely. On most routers, you can configure some protocols, such as remote authentication dial-in to the user service, so that these protocols can be used together with the verification server to provide encrypted and verified Router Access. Verification control can forward user authentication requests to verification servers on the backend network. The verification server can also require users to use two-factor verification to enhance the verification system. The two factors are the software or hardware token generation part, and the latter is the user identity and token pass code. Other verification solutions involve transferring security certificates within the Secure Shell (SSH) or IPSec.

3. disable unnecessary services

It is a good thing to have a large number of routing services, but many recent security events have highlighted the importance of disabling local services. It should be noted that disabling CDP on a router may affect the performance of the router's working principle. Another factor to consider is timing. Timing is essential for effective network operations. Even if the user ensures time synchronization during deployment, the clock may gradually lose synchronization after a period of time. You can use a service named Network Time Protocol (NTP) to compare effective and accurate time sources to ensure the hourly synchronization of devices on the network. However, the best way to ensure clock synchronization between network devices is not through a router, but to put an NTP server in the network segment of the DMZ protected by the fire wall, configure the server to only allow time requests to external trusted public time sources. On a vro, you rarely need to run other services, such as SNMP and DHCP. These services are used only when absolutely necessary.