Number of IP Addresses

TABLE 2 . 3 Number of IP Addresses Used in Figure 2.2
Description of Segment Number of IP Addresses Required
Server farm 300
Ethernet user segment 200
Serial link 2
Router interconnection switched subnet 4
2. Determine the subnet mask required to support the requirements defined in step 1, and
expand the table to list the subnet masks.
We can use our formula 2n – 2 = number of hosts to create a handy reference
chart to quickly determine how many hosts can be supported for any given subnet
mask, as shown in Table 2.4. The table goes up to only 1022 hosts, because
Cisco has a design recommendation that you should not have a non-routed network
segment with more than 500 hosts (due to performance problems caused
by broadcast traffic). To confuse you further, understand that some Cisco documentation
states that the number of hosts on a segment can be up to 800! Just
keep in mind the amount of traffic when making this decision.