Tcp/Ip Priority (Metric); Wan General; Figure 64 Spillover Algorithm Example - ZyXEL Communications ZyWall 5 Series User Manual

Figure 64 Spillover Algorithm Example

8.5 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.
Take a ZyWALL with multiple WAN ports as an 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.
For a ZyWALL with a single WAN port, if the WAN port 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
WAN port route acts as the primary default route. If the WAN port route fails to connect to the
Internet, the ZyWALL tries the traffic-redirect route next. 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 (or WAN 1 and
WAN 2) routes.

8.6 WAN General

Click NETWORK > WAN to open the General screen. Use this screen to configure load
balancing, route priority and traffic redirect properties.
Chapter 8 WAN Screens
ZyWALL 5/35/70 Series User's Guide
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