ZyXEL Communications ZyXEL ZyWALL 35 - Manual (Page 145)

ZyWALL 35 User’s Guide
Chapter 7 WAN Screens 143
Figure 50 Spillover Algorithm Example
7.5 TCP/IP Priority (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".
1 The metric sets the priority for the ZyWALL's routes to the Internet. Each route must
have a unique metric.
2 The priorities of the WAN port routes must always be higher than the dial-backup and
traffic redirect route priorities.
For example, lets say that you have the WAN operation mode set to active/passive and the
WAN 1 route has a metric of "2", the WAN 2 route has a metric of "3", the traffic-redirect
route has a metric of "14" and the dial-backup route has a metric of "15". In this case, the
WAN 1 route acts as the primary default route. If the WAN 1 route fails to connect to the
Internet, the ZyWALL tries the WAN 2 route next. If the WAN 2 route fails, the ZyWALL
tries the traffic-redirect route. In the same manner, the ZyWALL uses the dial-backup route if
the traffic-redirect route also fails.
The dial-backup or traffic redirect routes cannot take priority over the WAN 1 and WAN 2
routes.
7.6 Configuring General
Click WAN to open the General screen.