Session Border Controller Expert Sonus Networks Emphasizes the Importance of Policy
When it comes to IP communications, policy is a topic that is sometimes overlooked, but experts know that it is extremely important. I recently spoke with Mykola Konrad, general managers of the policy business unit at Sonus Networks (News - Alert), and Mohan Palat, from the product marketing team of the session border controller experts, about the importance of policy. Their comments were eye-opening.
First, Mohan explained to me that there are three types of policy: application policy, regarding when you can access an application; subscriber policy, which is applied to individual subscribers, depending on subscription level; and network policy, which consists of a broad spectrum of policies related to the core network, and including SLA policies, QoS policies and routing policies.
Solutions that deal with network policies have three components: policy enforcement, policy control and management, and a policy database. Sonus deals primarily in the control and management arena.
So, according to Konrad, when a service provider is looking for a session border controller, they should look not just at the core functions such as SIP operability and security, but also look at the policy set in the SBC. If there is intelligence there, it helps make things more efficient, in terms of proper routing. For example, if a session comes in and it is a video call, you might want it routed to a network that can handle the bandwidth. If it comes in on the wrong codec, you can shunt it somewhere else. Another important feature for service provider network policy is least cost routing, which moves the call to the cheapest path.
Another thing to keep in mind is a way to centralize your policy rules. From a service provider perspective, SPs need routing instructions and policies to come from somewhere, especially with all of the different SBCs and switches they have in the network. The PSX runs a SIP proxy, and has a decentralized policy server, which can make changes in one place to the entire network so it can route properly. There are also various specific network policy features that many service providers need. Recently, Iristel opted to use the Sonus PSX, which allows you to add or strip digits to route the call, a feature that Sonus does better than most by allowing very complex rules to determine how the digits should be manipulated and therefor how the call should be routed which typically allows carriers to save money.
In summary, the PSX policy solution can lower costs and carriers can pass those savings onto customers. Carriers can have more competitive offerings by having a centralized policy routing mechanism, allowing them to put out new offers, such as setting network traffic rules.
For more information on the Sonus PSX, click here.
Edited by Rich Steeves