Applications For Policy-Based Routing - Avaya G430 Manual

Policy-based routing
The Loopback interface is always up. You should attach a PBR list to the Loopback interface
if you want to route specific packets generated by the Branch Gateway to a specific next-
hop.
Unlike the case with other interfaces, PBR lists on the Loopback interface are applied to
packets when they leave the Branch Gateway, rather than when they enter.
Certain types of packets are not considered router packets (on the Loopback interface only),
and are, therefore, not affected by policy-based routing. These include RIP, OSPF, VRRP,
GRE, and keepalive packets. On the other hand, packets using SNMP, Telnet, Bootp, ICMP,
FTP, SCP, TFTP, HTTP, NTP, and H.248 protocols are considered routed packets, and are,
therefore, affected by policy-based routing on the Loopback interface.
Related topics:

Applications for policy-based routing

Setting up policy-based routing
PBR rules
Next hop lists
Editing and deleting PBR lists
PBR list commands in context
Policy-based routing application example
Summary of policy-based routing commands
Applications for policy-based routing
The most common application for policy-based routing is to provide for separate routing of
voice and data traffic. It can also be used as a means to provide backup routes for defined
traffic types.
Related topics:
Separate routing of voice and data traffic
Backup interface definition
Separate routing of voice and data traffic
Although there are many possible applications for policy-based routing, the most common
application is to create separate routing for voice and data traffic.
For example, the application shown in the following figure uses the DSCP field to identify VoIP
control packets (DSCP = 34, 41), VoIP Bearer RESV packets (DSCP = 43, 44), and VoIP
Bearer packets (DSCP = 46). Policy-based routing sends these packets over the T1 WAN line,
and sends other packets over the Internet. This saves bandwidth on the more expensive
external Serial interface.
588 Administering Avaya G430 Branch Gateway
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October 2013