ZyXEL N4100 Guia Do Utilizador

Chapter 5 WAN/LAN

N4100 User’s Guide

you entered. You don't need to change the subnet mask computed by the N4100 
unless you are instructed to do otherwise.

Every machine on the Internet must have a unique address. If your networks are 
isolated from the Internet, for example, only between your two branch offices, you 
can assign any IP addresses to the hosts without problems. However, the Internet 
Assigned Numbers Authority (IANA) has reserved the following three blocks of IP 
addresses specifically for private networks:

• 10.0.0.0     — 10.255.255.255
• 172.16.0.0   — 172.31.255.255
• 192.168.0.0 — 192.168.255.255

You can obtain your IP address from the IANA, from an ISP or it can be assigned 
from a private network. If you belong to a small organization and your Internet 
access is through an ISP, the ISP can provide you with the Internet addresses for 
your local networks. On the other hand, if you are part of a much larger 
organization, you should consult your network administrator for the appropriate IP 
addresses.

Note:  Regardless of your particular situation, do not create an arbitrary IP address; 

always follow the guidelines above. For more information on address 
assignment, please refer to RFC 1597, “Address Allocation for Private 
Internets” and RFC 1466, “Guidelines for Management of IP Address Space”.

The N4100 supports PPPoE (Point-to-Point Protocol over Ethernet). PPPoE is an 
IETF Draft standard (RFC 2516) specifying how a personal computer (PC) interacts 
with a broadband modem (DSL, cable, wireless, etc.) connection. The PPPoE 
option is for a dial-up connection using PPPoE.

For the service provider, PPPoE offers an access and authentication method that 
works with existing access control systems (for example RADIUS).

One of the benefits of PPPoE is the ability to let you access one of multiple network 
services, a function known as dynamic service selection. This enables the service 
provider to easily create and offer new IP services for individuals.

Operationally, PPPoE saves significant effort for both you and the ISP or carrier, as 
it requires no specific configuration of the broadband modem at the customer site.

By implementing PPPoE directly on the N4100 (rather than individual computers), 
the computers on the LAN do not need PPPoE software installed, since the N4100 
does that part of the task.