ccna r&s sample questions

ccna r&s sample questions..The first three bits of a Class C address are always HOo.The first four bits of a Class D address are always HlOo.The first five bits of a Class E address are always HllOo For example, if the first byte of the address is 1000 0001 (corresponding to a decimal value of 129), then it is a Class B address. Based on the value of the first few bits, it is easy to determine which class the address belongs to. The values of the first byte of a Class A address are 1-126: 0 is reserved for all IP addresses and 127 is reserved for tests, such as the ring of an interface.Back to the address. The value of the first byte of the class B address is 128 ~191, binary representation is 10000000-lOllllllo .The value of the first byte of the class C address is 192.223, binary representation is 11000000~11011111. .The value of the first byte of the class D address is 224 ~239, binary representation is 11100000 ~ 11101111o . 11101111o .The value of the first byte of the Class E address is 240-254: 255 is the reserved address for sending local broadcasts.Based on the first few values, it is easy to determine which class the address belongs to. Just look at the first digit in the dotted decimal representation,and see in which range it falls.The first byte of a class A address is 1.126, the first byte of a class B address is 128.191, the first byte of a class C address is 192.223, the first byte of a class D address is 224.239, and the first byte of a class E address is 240. 254O127 is reserved for loopback interfaces (internal testing). Also, remember the binary representation corresponding to these ranges. Once you have memorized what binary value the various IP addresses are prefixed with, you can tell whether it is a Class A, B, C, D, or E address by looking at the binary value of the first byte of the address.Within each network number, two addresses are reserved: the first address and the last address, which represent the network address and the broadcast address, respectively (often referred to as the directed broadcast address) Throughout the IP address space, two addresses are also reserved: 0.0.0.0 (the firstaddress) and 255.255.255.255 (the last address), which denote all IP addresses as well as local broadcast addresses (all devices should process datagrams using such addresses), respectively. Don't worry too much if you are confused about this, as IPv4 addressing is discussed in more depth in Chapter 6.3. Public and Private AddressesThere are two main types of addresses that can be used when assigning addresses to devices: public addresses and private addresses. Public addresses are Class A, Class B, and Class C addresses that can be used to access devices in public networks such as the Internet. The final assignment and management of public addresses is the responsibility of the Internet Address Assignment Authority (IANA), but you usually obtain a public address directly from an ISP, which applies to the upstream 5 address registries at.