User`s manual

P-660 Series Support Notes
89
All contents copyright © 2005 ZyXEL Communications Corporation.
Key Settings:
IP Alias 1
Toggle to 'Yes' and enter the second LAN IP address for the P-660. This will
create the second route in the enif0:0 interface.
IP Alias 2
Toggle to 'Yes' and enter the third LAN IP address for the P-660. This will create
the third route in the enif0:1 interface.
11. Using IP Policy Routing
What is IP Policy Routing (IPPR)?
Traditionally, routing is based on the destination address only and the router takes the
shortest path to forward a packet. IP Policy Routing (IPPR) provides a mechanism to
override the default routing behavior and alter the packet forwarding based on the
policy defined by the network administrator. Policy-based routing is applied to
incoming packets on a per interface basis, prior to the normal routing. Network
administrators can use IPPR to distribute traffic among multiple paths. For example, if
a network has both the Internet and remote node connections, we can route the Web
packets to the Internet using one policy and route the FTP packets to the remote LAN
using another policy. See the figure below.
Use IPPR to distribute traffic among multiple paths
Benefits
Source-Based Routing - Network administrators can use policy-based routing to
direct traffic from different users through different connections.
Quality of Service (QoS)- Organizations can differentiate traffic by setting the
precedence or TOS (Type of Service) values in the IP header at the periphery of the
network to enable the backbone to prioritize traffic.