Security practitioners must know a few online knowledge quiz
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Most of the current weak-power systems adopt the TCP/IP transmission method. We, the weak-weapons workers, need to know some simple network knowledge. The following network knowledge will definitely help you.
Q: Regarding the construction of long-distance network cables, in the case of units encountering such situations, the office building is too wide, and the internet access point is on the far left of the building, so that each floor has internet access. Fast, how to solve?
A: The support distance for data applications of balanced twisted pairs is 100 meters, which is defined by the international standard. Transmission of network signals over a distance of more than 100 meters will depend on the performance margin of the cabling system, the performance margin of the network equipment, and the construction of the site and many other uncertainties. It will not be able to obtain a quantitative indicator and it will not be available. Guarantee. For the case you mentioned, the standard practice is to set up two telecommunication rooms on a floor, and the horizontal cable division area is connected to the corresponding telecommunications room, ensuring that the length of the horizontal link (from the distribution frame to the information outlet) is not More than 90 meters.
Of course, you can also use a high-performance level, good quality cables and modules to make a direct point-to-point connection (more than 100 meters), but the support of this line for network applications is not guaranteed, that is to say it may be able to support xDSL or 10BASE-T signals, but may not support higher speeds.
The cabling design standards need to be followed. If it is too long, consider adding one relay in the middle, for example, using a switch or hub to connect two network cables. Do not risk excessively long, which will make network communication uncertain.
Q: Our company has a network port that is separated from the floor switch. After testing the switches, network ports, and the lines from the floor switches, the computer has no problem, but the problem is that the package can only be received without receiving packets. , For a few computers are useless. Can you tell us if the connection between the main switch and the floor switch is damaged during threading?
A: It seems that there may be a problem with the line. The premise is that this switch port and this computer port can normally send and receive data packets on other lines. It is recommended that you use the cabling tester to perform channel transmission performance tests on this line, that is, jumpers at both ends, connectors (distribution frames and information outlets) at both ends, and cables laid. The test criteria is based on the actual situation. Select Category 5E or 6 class. Also make sure that the jumpers used meet the line-sequencing criteria of T568A/B.
Q: What are the special requirements for Fiber Channel cabling in the data center room?
A: The fiber channel in the data center room is mainly used for 10 Gigabit network. Note the following points when selecting:
Transmission distance: OM3 multimode fiber is 300m-550m, single mode fiber is 10-40km
Fiber-optic connection devices and adapters are used for SC, LC, or port types based on network equipment
If the open cable bridge is used, the cable must have a corresponding fire rating (Class A or Class B)
Position of the optical distribution module (such as the top of the equipment cabinet, the open bridge, the wiring column header, and various wiring cabinets)
Q: Our company has a total of 3 floors of buildings with 80-100 computers per floor, and each floor has a computer distribution area of ​​over 300 square meters. For a case like this, what can I do to be able to complete the network layout more simply and effectively? The current vague intention is to place a Layer 3 switch in the center of each layer, and then connect the three switches through a PC server to achieve network sharing, and then implement Internet access through the router. Do not know if this will not work?
A: From the switching network architecture, an aggregation switch should be set up on the basis of Layer 3 switches. The aggregation access server serves as a data resource sharing platform for network users, and then the aggregation switch accesses the Internet through the appropriate router. The following should be noted point:
The wiring network architecture adapts to the architecture of the computer network;
Floor wiring closet settings Note that the horizontal cable does not exceed 90m in length;
The level of the cabling system is in line with the transmission bandwidth of the Ethernet switch. It is recommended to adopt the Super Category 5 or Category 6 cabling system, the trunk adopts multimode optical fiber (OM3), and configure the corresponding distribution module;
A more detailed wiring system architecture diagram should be designed, and the interoperability relationship with the network facilities should be made clear.
Q: After the network cabling is done, how do you check it? Need to consider from what aspects?
A: Please refer to GB50312-2007 “Comprehensive Cabling System Project Acceptance Specification†for the specific acceptance method. The following points should be noted for acceptance:
One hundred percent of all information points are tested for permanent links, and the connection model is in accordance with the specifications;
The test index items are determined according to the networks supported by the cabling system (eg, 100Mbit, 10Gigabit, 10GbE, and Ethernet). For details, see the standardized index parameter tables.
Determine the function and accuracy of the test meter;
Test results should be documented to save;
The quality of the project should be judged by the criteria (pass or fail).
The specification has a detailed and detailed description. If there are still problems, it can be proposed.