Typical Application - Interface Backup Via Policy-Based Routing - Avaya G250 Administration

Configuring WAN interfaces
Typical application – interface backup via policy-based routing
In the previous typical application (see
interface on page 181), the backup interface command is used to specify a backup
interface. This typical application illustrates an alternative to the backup interface
command, using policy-based routing (PBR) which configures a routing scheme for specified
traffic based on configured characteristics of the traffic. Thus, policy-based routing can be used
in combination with object tracking to configure a backup mechanism for interfaces.
For an example that uses policy-based routing as an alternative to the backup interface
command, replace the last four lines of the previous typical application with the example below.
The example creates a next hop list that sends the specified traffic to the WAN Fast Ethernet
interface, which is running PPPoE encapsulation. If the WAN Fast Ethernet interface becomes
unavailable, the next hop list routes the traffic to the Serial interface 2/1:1. PBR list 801 is
created and assigned to interface VLAN 1, so that traffic defined in PBR list 801 passing
through interface VLAN 1 is routed according to the next hop list.
Note:
You can define a static route over the WAN Fast Ethernet interface running
Note:
DHCP client. Then, the static route uses as the next hop the default router
learned from the DHCP server. This is useful for GRE tunnels which are defined
over the WAN Fast Ethernet running DHCP client. It is necessary to define static
routes in order to prevent loops. Therefore, the IP route command allows
configuration of static routes over WAN Fast Ethernet running DHCP client.
When the WAN Fast Ethernet is up, policy-based routing routes this traffic via the WAN Fast
Ethernet interface. When the track list defined in the previous typical application is down,
policy-based routing routes this traffic through the Serial interface 2/1:1. When the track list is
up again, the traffic is again routed through the WAN Fast Ethernet interface.
! Create PBR list 801. This list routes traffic from IP address
! 149.49.42.1 to IP address 149.49.43.1 according to next hop list 10.
!
ip pbr-list 801
name "list #801"
ip-rule 10
exit
!
! Assign PBR list 801 to interface Vlan 1.
!
interface Vlan 1
icc-vlan
ip pbr-group 801
ip address 149.49.42.254
exit
!
184 Administration for the Avaya G250 and Avaya G350 Media Gateways
next-hop list 10
source-ip host 149.49.42.1
destination-ip host 149.49.43.1
exit
Typical application – backup for the WAN Fast Ethernet
255.255.255.0