Reality Check: The outperforming core is crucial for successful EPC deployment

Editor’s Note: Welcome to our weekly Reality Check column. We’ve gathered a group of visionaries and veterans in the mobile industry to give their insights into the marketplace.
In my last article on the the agile packet core, we explored the flexibility needed for successful evolved packet core (EPC) deployments. In this article, we are focusing on the performance considerations necessary as you plan your LTE/EPC networks.
Beyond throughput – think transactions
The evolution to flat IP network architectures and large growth in mobile broadband traffic have a tremendous impact on not only throughput, but also transactions, latency, density and mobility.
Performance = transactions + throughput + density + low latency
A key consideration in the selection of the EPC is to find platforms that maximize and meet all the performance requirements. While the mobile Internet is about transactions, a misconception about the EPC is that transaction performance is only important in control plane elements, such as the MME and S4 SGSN. To meet the requirements of the session state and subscriber management in the mobile Internet, EPC elements require transaction performance that is significantly higher than equivalent 3G elements and IP routers.
Superior security
Mobile operators also realize the importance of expanding service offerings to address the home, enterprise and hotspot markets. Many operators are considering deploying LTE radios in non-traditional locations, such as in buildings or metro, on poles, or other less secure areas. To lower the cost of deploying networks, many operators are considering sharing radio locations.
The EPC can be used as the packet core for unsecured access networks, such as, Wi-Fi or femtocells, that leverage fixed broadband networks. While security has always been a top priority in mobile networks, these emerging new access networks and deployment scenarios require even stronger security.
Another key challenge for operators when deploying LTE will be ensuring the security of user data. Within the 3G packet switched domain, ciphering of NAS signaling and user data is performed within the radio network controller (RNC) and for 2G within the SGSN. The RNC and SGSN are typically located within the mobile operators secure core data centre ensuring that customer’s data cannot be wiretapped over the air interface or between the core datacenter and the NodeB (or Base Station for 2G).
In the EPC, ciphering of NAS signaling is performed within the MME, ensuring security of NAS signaling between the core datacenter and user device. However, ciphering of user data within the LTE is performed within the eNodeB. This presents a security risk for user plane data between the SGW deployed in a secure site and the remote eNodeBs as un-ciphered user data may be wiretapped within the backhaul network or at the eNodeB S1-U interface (there is a particular risk from physically unsecure deployments such as in-building eNodeBs). There is also the potential for eNodeB and SGW attacks (e.g., denial of service) performed by a device at the eNodeB site or within the access backhaul site masquerading as an eNodeB or SGW.
These security risks can be addressed by IPSec ciphering of the S1-U interface between SGW and eNodeB by enabling IPSec functions within the SGW. An IPSec ESP can encrypt and integrity protect 100 percent of user plane traffic with minimal impact on signaling and throughput capacity.
Available and beyond
Another key consideration for a successful EPC deployment is the availability of the network and its services. The elements within the mobile network are the backbone of an operator’s business. As a result, the design of the network must take into account availability and robustness of both the network and the services being offered.
Obviously, reliability can translate into revenue savings, as well as prevent revenue leakage and customer retention as lost service is lost revenue and customers. For example, many operators use external systems for billing to correlate usernames with IP addresses and billing information. If these products are not designed with stateful reliability, the end-to-end billing solution has lower reliability because of these “weak link” systems. This results in lost data and lost revenue.
Summary
Mobile operators succeed when they deliver an experience that meets and exceeds the expectations of their subscribers. By focusing on intelligence, flexibility and performance when planning out LTE/EPC networks, operators will be able to significantly enhance the user experience and monetize new services and applications.
Jonathan Morgan is senior director of product marketing for Starent Networks, a leading provider of infrastructure solutions that enable mobile operators to deliver multimedia services.