ccna 200-301 network simulator tools of the mind

ccna 200-301 network simulator tools of the mind.1. Binary to Decimal ConversionGiven a binary number (1101) 2, the corresponding decimal number is 1X2°+0X21+1X22+1History 3=1+0+4+8= 13. The IP address contains 32 bits, and each 8 bits are represented by a decimal number, so each decimal number is at most (1111111) 2=1+2+4+8+16+32+64+128= 255. 255, from here we can see, the IP address of the decimal number of representation, should not appear more than 255 value, from the above calculation, we can see out in the 8-bit binary number representation, the highest bit of 1 represents the decimal number of 128, the next higher bit of 1 represents the decimal number of 64, and then the next is 32 ................................................................................................................................................................... The lowest 1 represents the decimal number 1° According to this correspondence, in most cases, no calculation is needed to arrive at the decimal number corresponding to the binary number, for example (10000001) = 128+1=129.2,Decimal to binary conversionMany readers are afraid of decimal to binary conversion, because the "divide by 2 to get the remainder" method is too troublesome and error-prone. Here is a simple and less error-prone method, let's call it the "round up method", which is to round up the corresponding decimal numbers in the IP address into a combination of 128,64,32, 16,8,4,2,1, etc., and then fill in 1 if the number appears, and 0 if the number does not appear, and finally get out the 8-bit binary group is The resulting 8-digit binary group is the binary number corresponding to the decimal number. For example, to convert the decimal numbers 130 and 49 into binary numbers, 130=128+2=(10000010) 2,49=32+16+1=(00110001) 2o Readers may worry, if there is a large decimal number how to convert ah? This method is simple enough, and not easy to make mistakes, the reader just need to practice a little, you can master.2.5.2 IP Address Classification ...An IP address consists of two main parts: a part that identifies the network number to which the address is subordinate; and a part that specifies the host number of a particular host on that network. Network numbers are assigned by the Internet Authority, and host addresses are assigned uniformly by the administrators of individual networks. Thus, the uniqueness of the network address and the uniqueness of the host address within the network ensure that IP addresses are globally unique (with the exception of private address segments reserved for use by certain networks) OTo accommodate networks of different sizes, the IP address space is divided into five different address classes, namely classes A, B, C, D, and E, as shown in Table 2.5.1, with classes A, B, and C being the most commonly used, class D being used for multicast, and class E being used for scientific research.IP address type First byte decimal range Binary fixed highest bit Binary network bit Binary host bit Number of hosts per networkA 0-127* 0 8 bits 24 bits 224-2B 128-191 10 16 bits 16 bits 216-2