160 31 Days Before Your CCENT Certification Table 1-11 Class A, B, C, D, and E Networks Subnet Mask and Number of Network (N) and Host (H) Octets 255.0.0.0 N.H.H.H 255.255.0.0 N.N.H.H 255.255.255.0 N.N.N.H H.H.H.H Research Bits in the Network Address 8 16 24 28 Research Class Class A Class B Class C Class D Class E Binary Start 0 10 110 111 1111 First Octet Range 1­126 128­191 192­223 224­239 240­255 Hosts About 16 million 65,535 254 Multicast Research Table 1-12 Class Class A Class B Class C Loopback RFC 1918 Private Networks and the Loopback Address Range (Number of Addresses Available) 10.0.0.0­10.255.255.255 (more than 16 million) 172.16.0.0­172.31.255.255 (more than 65,000) 192.168.0.0­192.168.255.255 (254) 127.0.0.0­127.255.255.255 Table 1-13 Slash Format Last Octet in the Mask (in Decimal) Bits Borrowed Total Subnets Total Hosts Useable Hosts Borrowed Bits to Divide a Default Class C Network /25 128 /26 192 /27 224 /28 240 /29 248 /30 252 /31 254 /32 255 1 2 128 126 2 4 64 62 3 8 32 30 4 16 16 14 5 32 8 6 6 64 4 2 7 -- -- -- 8 -- -- -- Day 19: Assign Addresses Static address assignment on a host guarantees that it will always have the same IP address on the network. Hosts that provide services such as servers and printers usually receive static IP address- es. DHCP provides a manageable way to maintain a dynamic addressing scheme.