8/3/2023 0 Comments Cisco subnetting chartNotice that it is no more than taking the information just learned on the previous slide and performing a little addition. You will need to know this off the top of your head as we delve deeper into subnetting and when you take the CCNA test. Here is a binary chart that is best just to memorize. So explaining a couple of examples on the slide are as follows:Ĩ5 equals 01010101 which equates to 64 + 16 + 4 + 1 = 85ġ31 equals 10000011 which equates to 128 + 2 + 1 = 131 simple really. The binary numbers are placed in a value spot starting at the right and moving left, with each spot having double the value of the previous spot. What interests us in binary numbering is the value represented in a decimal format-the typical decimal format being our base ten number scheme we’ve all used since kindergarten. Typically, you count either four or eight bits together, with these being referred to as a nibble or a byte, respectively. The digits used are limited to either a 1(one) or a 0 (zero), with each digit being called one bit. We discussed this in chapter 1, but it is important enough to review at this point: So, if you see an IP address that starts at 192 and goes to 223, you’ll know it is a Class C IP address. Following the same process as the previous classes, convert from binary to decimal to find the range. If you turn the other six bits all off and then all on, you will find the range for a Class B network:įor Class C networks, the RFCs define the first two bits of the first octet always turned on, but the third bit can never be on. In a Class B network, the RFCs state that the first bit of the first byte must always be turned on, but the second bit must always be turned off. This means a Class A address must be between 0 and 126 (127 is reserved for loopback address). The designers of the IP address scheme said that the first bit of the first byte in a Class A network address must always be off, or 0. Routing protocols such as RIP version 1 or IGRP do not recognize VLSM as they are classful routing protocols. In order to properly route IP packets utilizing VLSM, a classless routing protocol like OSPF, EIGRP or RIP version 2 must be used. Fortunately with the use of Variable Length Subnet Masks (VLSM), classfull boundaries can be removed to make better use of address space. The number of possible hosts is a Class A address are much greater than the number of possible hosts in a Class C address.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |