Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 999)

Quality of Service (QoS) Introduction
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 38.27
Policy-Based Routing
Policy based routing provides a means to create multiple paths to the same destination.
The specific path that any particular packet will take can be based on configurable
network metrics such as priority, protocol, or VLAN membership. For example, policy
based routing can implement policies to allow or deny paths based on the identity of user
devices, application, or packet sizes.
Practical Example
The example shown makes use of policy based routing to achieve the following:
1. Ensure that traffic being sent between local VLANs is switched normally.
2. Selects a particular egress path for traffic destined for the wide are networks.
Configuration Overview
A large government building houses employees from three separate government
departments: Heath, Welfare, and Employment. Each department has its own local
subnet, and an associated VLAN; these are:
■ 10.10.0.0/16 Health, VLAN 10
■ 10.20.0.0/16 Welfare, VLAN 20
■ 10.30.0.0/16 Employment, VLAN 30
Enquiries to each department are fed through a common Allied Telesis switch. The switch
has 3 uplink ports, each of which (for simplicity) will be in a different VLAN and each will
supply a connection to its relevant government department and to the Internet via each
departments particular ISP (Internet Service Provider). These are:
■ Port 1.0.1 Health Uplink, VLAN 110
■ Port 1.0.5 Welfare Uplink, VLAN 120
■ Port 1.0.21 Employment Uplink, VLAN 130
This configuration is illustrated in Figure 38-10 :