ZyXEL Communications 128L Manual De Usuario

 

This chapter shows you how to configure your Prestige for TCP/IP. 
Depending on your particular applications, you will need to 
configure different menus. For instance, Internet access is the most 
common application of TCP/IP. For this application, you should 
configure Menu 4. We will illustrate the configuration for other 
applications in the following sections. 

A subnet mask is a 32-bit quantity that, when logically ANDed with an 
IP address, yields the network number. For instance, the subnet masks 
for class A, B and C without subnetting are 255.0.0.0, 255.255.0.0 
and 255.255.255.0, respectively. 

To create more network numbers, you shift some bits from the host ID 
to the network ID. For instance, to partition a class C network number 
192.68.135.0 into two, you shift 1 bit from the host ID to the network 
ID. Thus the new subnet mask will be 255.255.255.128; the first 
subnet will have network number 192.68.135.0 with hosts 
192.68.135.1 to 192.68.135.126 and the second subnet will have 
network number 192.68.135.128 with hosts 192.68.135.129 to 
192.68.135.254. 

It is recommended that you use the same subnet mask for all physical 
networks that share an IP network number. The table below lists the 
additional subnet mask bits in dot decimal notations. To use to following 
table, write down the original subnet mask and substitute the higher 
order 0s with the dot decimal of the additional subnet bits. For instance,