A routed deployment is one method of deploying a BIG-IP system directly in the path of traffic, such as between a WAN router and LAN switch. In routed mode, the BIG-IP system is nontransparent on the network, with separate LAN and WAN self IP addresses on each side. This setup ensures that requests from clients go to the BIG-IP system, which optimizes the traffic before it reaches the server.
This illustration shows a pair of BIG-IP systems in a routed deployment (Site B) on one side of the WAN, and a one-arm deployment on the other side.
The BIG-IP systems work in pairs on opposite sides of the WAN to optimize the traffic that flows between them through an iSession connection. A simple point-to-point configuration might include BIG-IP systems in data centers on opposite sides of the WAN. Other configuration possibilities include point-to-multipoint (also called hub and spoke) and mesh deployments.
The following illustration shows an example of the flow of traffic across the WAN through a pair of BIG-IP devices. In this example, traffic can be initiated on both sides of the WAN.
Each BIG-IP device is an endpoint. From the standpoint of each BIG-IP, it is the local endpoint. Any BIG-IP device with which the local endpoint interacts is a remote endpoint. After you identify the endpoints, communication between the BIG-IP pair takes place in an iSession connection between the two devices. When you configure the local BIG-IP device, you also identify any advertised routes, which are subnets that can be reached through the local endpoint. When viewed on a remote system, these subnets appear as remote advertised routes.
To optimize traffic, you create iApps templates to select the applications you want to optimize, and the BIG-IP system sets up the necessary virtual servers and associated profiles. The system creates a virtual server on the initiating side of the WAN, with which it associates a profile that listens for TCP traffic of a particular type (HTTP, CIFS, FTP). The local BIG-IP system also creates a virtual server, called an iSession listener, to receive traffic from the other side of the WAN, and it associates a profile that terminates the iSession connection and forwards the traffic to its destination. For some applications, the system creates an additional virtual server to further process the application traffic.
The default iSession profile, which the system applies to application optimization, includes symmetric adaptive compression and symmetric data deduplication.
Before you configure an iSession connection on the BIG-IP system, make sure that you have completed the following general prerequisites.
If you are configuring a BIG-IP system in routed mode, you configure separate self IP addresses for the internal and external interfaces. Also, you need to create a passthrough virtual server that you can use to verify the connection before you try to optimize traffic.
|LAN VLANs||Select the VLANs that receive incoming LAN traffic destined for the WAN.|
|WAN VLANs||Select the VLANs that receive traffic from the WAN through an iSession connection.|
After you complete the tasks in this implementation, the BIG-IP system is configured in a routed deployment. For symmetric optimization using an iSession connection, you must also configure the BIG-IP system on the other side of the WAN. The other BIG-IP deployment can be in bridge, routed, or one-arm mode.