user manual

P-660R/H-D Series User’s Guide
73 Chapter 6 WAN Setup
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.
6.3 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).
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 Prestige (rather than individual computers), the
computers on the LAN do not need PPPoE software installed, since the Prestige does that part
of the task. Furthermore, with NAT, all of the LANs’ computers will have access.
6.4 Traffic Shaping
Traffic Shaping is an agreement between the carrier and the subscriber to regulate the average
rate and fluctuations of data transmission over an ATM network. This agreement helps
eliminate congestion, which is important for transmission of real time data such as audio and
video connections.
Peak Cell Rate (PCR) is the maximum rate at which the sender can send cells. This parameter
may be lower (but not higher) than the maximum line speed. 1 ATM cell is 53 bytes (424 bits),
so a maximum speed of 832Kbps gives a maximum PCR of 1962 cells/sec. This rate is not
guaranteed because it is dependent on the line speed.