There is a lot of talk in the industry about DPI and mobile operators. There was an article on Light Reading in 2008 titled “DPI (hearts) LTE” that explored this topic. The general belief is that mobile operators MUST have DPI in their network to survive and compete, due to a number of bandwidth and usage challenges. Operators are bracing for users that will treat their mobile connection in the same way that they use their fixed broadband networks today (i.e. streaming video, file downloads, peer-to-peer, etc). Since laptops are expected to be one of the earliest LTE devices supported in many of the early LTE deployments, the data requirements of LTE must be addressed from the initial deployment.

The debate has been stoked by the inclusion of a loose requirement in the SAE-GW for Deep Packet Inspection, aimed at application classification and QoS at Layer 7 (not traditional router-style Layer 4 filters). Many traditional GGSN/PDSN gateway vendors have begun to message that DPI is a part of their LTE solutions, and the expectations of mobile operators are rising daily. RFPs are coming at a rapid pace from mobile operators, and every one includes a request for information on how DPI can be deployed in an LTE network.

At Procera, our experiences working with mobile operators have convinced us that DPI will be a key technology for LTE deployments. Mobile operators need network intelligence on what is happening on their network, and the ability of DPI to reach back into the access network and correlate individual subscribers to their location in the Radio Access Network and manage congestion is a vital requirement to ensure a good Quality of Experience for operators. Tight integration with the BSS and OSS backoffice systems ensures that the DPI systems provide a single point of contact for network visualization that includes subscriber, device, location, service plan, and application knowledge. This information can also be used for billing, allowing service providers to create flexible billing packages based on location, time of day, on-net or off-net application, roaming, or usage volume.

That is all well and good, but how does it relate to LTE? These requirements are also valid for 3G deployments, and are even deployed on some 2G networks today. The challenge for LTE and DPI pushes the boundaries of the DPI that is deployed on networks today because the scalability, performance, and service expectations will exponentially increase with LTE deployments over 3G. 10G links are a minimum performance requirement, and the bandwidth and session count per user will skyrocket as mobile devices become more capable of multi-tasking and cloud-based applications take hold. It will not be acceptable to do “a little” DPI, as all traffic will be required to receive DPI treatment. LTE networks will be service and application oriented, as operators will push new applications as a way to justify the higher rates for LTE services, and DPI will be required to recognize and prioritize real-time services.

Many providers of Mobile Gateway solutions will also claim this functionality, and try to convince operators that their integrated DPI solution is “good enough” to provide equivalent functionality for a LTE deployment. But there are some issues with integrated solutions that should cause operators to pause before deploying an integrated solution. The first is that an integrated solution ties you to a single vendor for your deployment, and ties your upgrade in capabilities to what your integrated solution can be upgraded to. Standalone solutions provide more flexibility, and give you more leverage as best-in-breed solutions increase in performance and capabilities. Integrated solutions also tend to suffer from performance and scalability decreases when additional functions are activated in the systems, of which DPI has traditionally been one of the most processor intensive applications on a CPU module. The “single chassis” argument that is commonly made by integrated vendors is also often an invalid one, as the performance and scalability requirements of a full DPI deployment often exceed the capabilities of an integrated chassis. Although LTE deployments will start small, requiring additional chassis systems just to activate DPI functionality will negate any advantage of an integrated solution.

The story of LTE and DPI is just starting to be written, but we are sure that the two will be tightly intertwined together going forward.