Policy-Based Stack Selection

The Oracle® Enterprise Session Border Controller performs dynamic, policy-based stack selection when an H.323 call arrives at the Oracle® Enterprise Session Border Controller and a configured associated outgoing stack cannot be found.

For policy-based stack selection, the Oracle® Enterprise Session Border Controller refers to local policies that contain address information that corresponds to incoming traffic. This information is contained in the local policy’s To address and From address fields. For the source, this information is matched with the Q.931 calling party number; if there is no calling party number, the H.323 source address is used. For the destination, this information is matched with the called party number; if there is no called party number, then the H.323 destination address is used.

After a local policy corresponding to the incoming traffic has been found, the Oracle® Enterprise Session Border Controller looks at the next hop value (a local policy attribute) and selects a local policy for the basis of stack selection. If the local policy look-up yields multiple local policies with the same next hop values, but with different cost values, the local policy with the lowest cost value is selected.

If a realm is not defined in the local policy, the next hop address is then matched against the address prefix values for the realms that are configured for the system. Thus, the Oracle® Enterprise Session Border Controller discovers the realm for this traffic. Using this realm information, the Oracle® Enterprise Session Border Controller performs stack selection. It uses the first configured H.323 stack in the Oracle® Enterprise Session Border Controller’s configuration that has a realm ID value matching the identifier field of the realm with the appropriate address prefix.

In the following example, the local policy matching yields a local policy with a next hop value of 169.125.4.1, which corresponds to RealmB. The outgoing stack selected is Stack 3 because it is the first stack to have been configured with RealmB as the realm ID.

Policy-Based Stack Selection