ZyXEL Communications Prestige 662HW Series, Руководство пользователя

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Prestige 662HW Series User’s Guide
WAN Setup 7-1
Chapter 7
WAN Setup
This chapter describes how to configure WAN settings.
7.1 WAN Overview
A WAN (Wide Area Network) is an outside connection to another network or the Internet.
See the Wizard Setup chapter for more information on the fields in the WAN screens.
7.2 Metric
The metric represents the "cost of transmission". A router determines the best route for transmission
by choosing a path with the lowest "cost". RIP routing uses hop count as the measurement of cost,
with a minimum of "1" for directly connected networks. The number must be between "1" and "15"; a
number greater than "15" means the link is down. The smaller the number, the lower the "cost".
The metric sets the priority for the Prestige’s routes to the Internet. If any two of the default routes
have the same metric, the Prestige uses the following pre-defined priorities:
♦ Normal route: designated by the ISP (see section 7.6 )
♦ Traffic-redirect route (see section 7.7 )
♦ WAN-backup route, also called dial-backup (see section 7.7 )
For example, if the normal route has a metric of "1" and the traffic-redirect route has a metric of "2"
and dial-backup route has a metric of "3", then the normal route acts as the primary default route. If
the normal route fails to connect to the Internet, the Prestige tries the traffic-redirect route next. In the
same manner, the Prestige uses the dial-backup route if the traffic-redirect route also fails.
If you want the dial-backup route to take first priority over the traffic-redirect route or even the normal
route, all you need to do is set the dial-backup route’s metric to "1" and the others to "2" (or greater).
IP Policy Routing overrides the default routing behavior and takes priority over all of the routes
mentioned above (see the
IP Policy Routing chapter).
7.3 PPPoE Encapsulation
The Prestige 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). PPPoE provides a login and authentication method that
the existing Microsoft Dial-Up Networking software can activate, and therefore requires no new
learning or procedures for Windows users.
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.