ZyXEL Communications Prestige 653HWI series, Руководство пользователя

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Prestige 653HWI Series User’s Guide
7-2 WAN Setup
Using ISDN-DCP, the Prestige acts as a DCP server. By default, the Prestige listens for DCP messages on
TCP port number 2578 (the Internet-assigned number for RVS-COM DCP). When the Prestige receives a
DCP message from a DCP client i.e., a workstation, the Prestige processes the message and acts on it. Your
Prestige supports all the DCP messages specified in the ISDN-DCP specification.
7.4 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 between the Prestige’s two backup routes. If these routes both have the same
metric, the Prestige uses the following pre-defined priorities:
1. Traffic-redirect route (see
section 7.9 )
2. ISDN WAN-backup route, also called dial-backup (see section 7.9 )
For example, if traffic redirect has a metric of "15" and the ISDN-backup route has a metric of "15", then the
traffic-redirect acts as the primary default route. Should the DSL route fail to connect to the Internet, the
Prestige first tries the traffic-redirect route. 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, all you need to do is set
the dial-backup route’s metric to "14" and the ISDN metric to "15" (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).
7.5 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.