BGF Topology with Multiple Virtual BGFs and Gateway Controllers Overview
This topic describes the use of multiple virtual BGFs and controllers in a router
You can run up to eight concurrent virtual BGFs in a router when using the Routing Engine to run the virtual BGF. You can run up to 32 concurrent virtual BGFs when using control services PICs by assigning up to 8 virtual BGFs on each of 4 control services PICs.. Each virtual BGF is connected to a gateway controller over its own PGCP connection. One virtual BGF can connect to one gateway controller at the same time. Multiple virtual BGFs running in the Routing Engine or on the same control services PIC can share a single data service PIC. A single virtual BGF cannot span more than one data PIC or MS-DPC or more than one control PIC.
By creating multiple virtual BGFs, you can:
- Deploy different policy and quality-of-service (QoS) characteristics in your network.
- Scale your infrastructure by using multiple services PICs or MS-DPCs to control voice traffic.
Figure 1 shows a topology with multiple virtual BGFs and gateway controllers. This topology enables one virtual BGF and one MultiServices PIC to continue handling gate requests and forwarding packets on open gates even when the other PIC fails.
Figure 1: Topology with Multiple Virtual BGFs and Gateway Controllers
You can have multiple gateway controllers configured for one virtual BGF. When a virtual BGF begins running on the router, it attempts to set up a connection to the first configured gateway controller. Each virtual BGF can have one active gateway controller and one or more standby gateway controllers. In case of a gateway controller failure or in case of the gateway controller sending instructions to the virtual BGF, the virtual BGF can switch to another gateway controller. Figure 2 shows an active and standby gateway controller connected to virtual BGF 2.
Figure 2: Active and Standby Gateway Controllers
If the PGCP connection between the virtual BGF and the gateway controller is lost, the virtual BGF attempts to reconnect to the gateway controller. If the virtual BGF cannot reconnect to the gateway controller, it traverses its list of gateway controllers until it successfully connects to one of the gateway controllers.
