Soft Test Network engineer Calculation Formula finishing (all)

Network Engineer Examination is the National computer technology and software level examination of an intermediate qualification examination, through the examination of qualified personnel in accordance with the requirements of the application Department of network system planning, design and installation of network equipment and hardware debugging work, can carry out network system operation, maintenance and management, can be efficient, reliable, Manage network resources securely, as a network professional to the system development of technical support and guidance, with the actual work ability of engineers and business level, can guide network administrators to engage in network system construction and management work. Network Engineer Exam is a popular soft test, how to pass the exam is the vast number of candidates want to know, the following Greek soft test college for you to bring the network engineer to prepare for the Battle of the test, professional teachers to arrange the network of Engineers exam-related calculation formula, help you preparation.

Calculation formula arrangement of soft test network engineer

Calculation of pipelining

Assuming that there is some type of task that can be divided into n subtasks, each subtask takes time t, the time required to complete the task is NT. In the traditional way, the time required to complete a K-task is knt. With pipelining, the time taken is nt+ (K1) T.

address addressing of memory

The main memory (memory) is a random access method, each block of data needs to be encoded, and in the main memory, the data block is identified in Word, that is, each word an address, usually using a 16 binary representation. For example, by byte addressing, where the address is from A4000H~CBFFFH, there is (CBFFFA4000) + 1 bytes, or 28000H bytes, or 163,840 bytes, equal to 160KB.

Access Memory Time

If the cache has an access hit rate of H (usually 1h is the cache's loss of efficiency), and the cache's access cycle time is T1, the main memory access cycle time is T2, then the average time to the entire system should be:

t3=ht1+ (1h) T2

Channel Bandwidth

Bandwidth: Refers to the bandwidth of the transmitter and the characteristics of the transmission media, usually expressed in hertz or cycles per second (for analog channels, its channel bandwidth w maximum frequency F2 lowest frequency F1)

Hamming Calibration

To calculate the Hamming check code, the first thing to know is that the Hamming check code is placed on the power of 2, that is, "1,2,4,8,16,32 ...", and for the information bit is the original data of M, it is necessary to add K-bit verification code, which satisfies the m+k+1<.

Calculation of delay

Transmission delay (transmit delay) = data frame length/channel bandwidth

Propagation delay = Channel length/propagation speed of electromagnetic waves in the channel

IP Address calculation related

In order to help you in the exam faster and more accurately calculate the network number/subnet number, broadcast address, assignable network/subnet address, valid subnet number, number of hosts, number of subnets, the following is a summary of the answers to common questions.

(1) Basic Subnet Division, take network number: Class A retains the first bit, The back full 0 (such as IP address: 10.1.0.0, network number: 10.0.0.0), Class B reserved the first two bits, followed by 0 (such as IP address: 131.2.3.0, network number: 131.2.0.0), Class C reserved the first three bits, followed by all 0 (such as IP address: 192.168.1.5, network number: 192.168 .1.0).

(2) Complex subnet division, take the network number: first, the mask 255 portion of the corresponding part of the copy, and then the non-255 parts, the mask and IP address are turned into binary number for "and" operation. For example: The IP address is 192.168.1.100, the subnet mask is 255.255.255.240, the first three numbers are copied, and the last part is first turned into a binary number and then the "and" Operation (01100100and11110000=01100000, that is, 96), Get 192.168.1.96.

Given the IP address and mask, the network/subnet broadcast address can be computed according to the rule: "The network/subnet number is the smallest number in the network/subnet, the broadcast address is the maximum numeric value in the network/subnet, and the valid and assignable address in the network is the IP address between the network/subnet number and the broadcast address".

(1) Basic subnet Division, take broadcast address: Mask 255 of the partial copy, the portion of 0 is changed to 255, for example: The IP address is 131.1.0.4, the subnet mask is 255.255.0.0, the broadcast address is 131.1.255.255.

(2) Complex subnet division, take broadcast address: For 255 parts copy, 0 parts to 255, for the other part of the first with 256 minus the worth of X, and then find the corresponding number in the IP address of the nearest x multiple y, and then y minus 1. For example: IP address 131.4.101.129, subnet mask 255.255.252.0 then the first 255, 0 to finish processing, get 131.4. 255, then with the 256252=4, with 101 the nearest multiple of 4 is 104, so the broadcast address is 131.4.103.255.

Soft Test Network engineer Calculation Formula finishing (all)