Compatible Systems 5.4 - Manual (Page 285)

Appendices 279
Chart 3: Subnetted Class C Host Ranges
v Note: The lowest calculated address in each range (0 in the traditional C
range) is not shown, cannot be used, and is skipped in the chart. The highest
address in each range (255 in the traditional C range) is also not shown, and
is the broadcast address for the subnet.
With each mask above, the 1’s in the binary value represent the network
portion, and the 0’s represent the host portion (128 is 10000000, 192 is
11000000, etc.). As you use more bits to represent the network portion, fewer
bits are left to use as host addresses.
The same idea can be extended to Class A and Class B networks.
Broadcast Addresses
The broadcast address is the address to which devices send packets meant for
all other devices. All devices “listen” for broadcasts in addition to their own
address. Address Resolution Protocol (ARP) packets and routing information
are examples of packets sent to the broadcast address. Most often, the broad-
cast address is the last address in the network (or subnet) with the host portion
being all 1’s binary (some networks use 0.0.0.0 or 255.255.255.255,
however.). Below are some examples of broadcast addresses.
S UBNET M ASK H OST R ANGES
255.255.255.0 1-254 (traditional C)
255.255.255.128 1-126, 129-254
255.255.255.192 1-62,65-126,129-190,193-254
255.255.255.224 1-30,33-62,65-94,97-126,
129-158,161-190,193-222,
225-254
255.255.255.240 1-14,17-30,33-46,49-62,
65-78,81-94,97-110,
113-126,129-142,145-158,
161-174,177-190,193-206,
209-222,225-238,241-254
255.255.255.248 1-6,etc.