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.
What would it be like to drive in a city without stoplights, traffic signs and speed limits? In a word, chaos. But that’s exactly what would happen if wireless carriers weren’t clear on what tools they can use to manage their traffic.
Traffic management is a timely topic for a couple of reasons. First, wireless data traffic continues to skyrocket, thanks to the popularity of smart phones and connected tablets, inexpensive cellular modems, and the proliferation of mobile broadband technologies such as HSPA, HSPA+ and EV-DO. Every subscriber with a mobile broadband subscription wants high speed data access whenever and wherever they are.
Second, the Federal Communications Commission and Congress continue to debate the need for net neutrality. Although that debate has centered on wired networks such as cable and DSL, wireless mobile broadband continues to get attention, if only because more and more consumers and businesses are using cellular networks to access Internet-based services. Net neutrality sounds simple and desirable, but it’s not. Traffic management may sound simple, but the techniques used by wireless operators are complex and evolving. Mobile wireless networks fundamentally are more constrained than their wired counterparts. Given zoning challenges, wireless operators cannot simply add cell sites whenever and wherever they’re needed, and the physical limits on the amount of bits that can be shoehorned into each sliver of scarce spectrum create additional constraints.
This reality makes it even more challenging for carriers to meet their customers’ and business partners’ quality-of-service expectations. Effective traffic management is important for meeting these expectations, as well as for attracting and retaining investors, who want carriers to make the most efficient use of their existing spectrum and infrastructure before spending and investing billions for more capacity. Mandated traffic management rules in the name of net neutrality could cast doubt on what management techniques are permissible. Such doubt, in a very dynamic, congested environment, might prevent carriers from using techniques necessary to optimize QoS for the majority of customers.
The nuances of wireless network management aside, it’s unlikely that the net neutrality debate will be resolved quickly or easily. The good news is that in the meantime, wireless carriers have a growing selection of fair and objective traffic-management tools to minimize the chances that their customers and their business partners will get stuck in a jam.
Who’s making decisions?
By deciding on traffic techniques, carriers can manage their customers experiences. The carrier will have the real time information to choose among techniques, rather than a regulator. The better the technique selected by a carrier, the better it is for most customers, carriers and the entire mobile broadband industry. As an example, imagine a master chef with a limited amount of sirloin steak preparing dinner for many hungry customers. Most customers will be better off if the chef provides a balanced meal of salad-steak-potatoes to all his customers, rather than allow one greedy customer to consume all of the sirloin and serve the other customers a dinner of only salad and potatoes.
A major challenge to traffic management is that many factors are partly or entirely out of carriers’ control:
–Customer equipment. The carrier has more control if the customer buys the smart phone or other device from it or one of its business partners, such as a tablet or laptop vendor. But this control is slipping as it becomes easier for customers to buy devices that aren’t locked to a specific carrier, a freedom that’s particularly common in the GSM/HSPA world. Carriers also have less control over dongle modems because unlike most handsets, they can be plugged into a variety of devices with a variety of bandwidth-related capabilities.
In the case of smart phones, carriers have limited control over the applications that their customers can install. Some apps are bandwidth-intensive, and others can contain malware that uses significant amounts of network resources while providing no benefit to the unsuspecting user. Once hacked or “jailbroken,” smart phones can create additional traffic headaches for the carrier and its other customers.
–Radio Access Network (RAN). The RAN can be divided into two realms – base stations and the air link. Carriers have iron-clad control over base stations, which is steadily being enhanced with a mixture of standards-based and vendor-specific traffic-management tools. Over the past couple of years, more and more carriers have begun using Wi-Fi, femtocells or both for additional traffic-management options relative to their base stations.
Carriers have less control in the second RAN realm, the air-link. Interference is just one, easily understood example of the myriad static and dynamic factors that affect a particular cell site’s ability to shoulder its part of the area’s traffic load.
–Backhaul. As wireless data traffic skyrockets, many carriers are migrating their backhaul from T1s to Ethernet, which offers superior scalability from both a technical and financial perspective. By upgrading their backhaul capacity, carriers are ensuring that these links aren’t a traffic bottleneck.
–Core. As with the RAN, carriers have tight control over core network elements such as GGSNs and SAE gateways, so there are ample traffic-management opportunities.
–Content. For mobile users, content increasingly is king. Carriers have more options for managing content-related traffic when it originates from them, their customers or their business partners. It’s just the opposite with content from unaffiliated third parties, such as popular video streaming sites.
But when an unaffiliated third-party service provides a poor user experience – such as freezing and pixelization in the case of streaming video, whom do customers blame or call? They call their wireless carrier! Hence the importance of a wide selection of network tools that give carriers more control over traffic in order to respond to customers’ expectations.
Given that a carrier cannot control all the factors impacting its customers’ experiences, it is vital that the carrier at least have the ability to decide among techniques, rather than be dictated to by regulators on what techniques are permissible.
Developments for managing customer expectations
The Third Generation Partnership Project (3GPP), the leading industry standards group of the GSM family of technologies, is an example of how the wireless industry is proactively addressing traffic management to help all customers. To meet the unique QoS requirements of a particular service — such as web page fetches or streaming video — 3GPP defines an end-to-end QoS architecture for UMTS‐HSPA/HSPA+ and LTE networks.
This architecture includes parameters such as traffic class (conversational, streaming, interactive and background), maximum bit rate, guaranteed bit rate, delivery order, transfer delay, traffic handling priority and allocation and retention priority. All of these parameters give carriers more flexibility for managing traffic.
For example, conversational and streaming classes are used for real‐time traffic flows, such as video telephony, which are highly sensitive to delay. By comparison, interactive and background classes are used for less delay-sensitive services, such e-mail and web browsing. These mechanisms ensure that, for example, an emergency responder’s video stream isn’t delayed by e-mail traffic.
The following table provides some examples of 3GPP QoS parameters.
[Source: 3G Americas: Traffic Management for Mobile Broadband Networks, August 2010; www.3gamericas.org]
If all of this sounds complex, that’s because it is. That complexity also is a major reason why traffic management decisions should not be dictated by regulators. Instead, Congress and the FCC should use a light regulatory policy hand by allowing market dynamics to unfold, leaving carriers, vendors and standards bodies to develop and implement the traffic-management tools that the marketplace demands.
Chris Pearson is the President of 3G Americas, a mobile industry association representing the 3GPP family of technologies throughout the Americas region. The association recently published a white paper, Traffic Management Techniques, Living in an Orthogonal World, available for free download at www.3gamericas.org, that details the importance of traffic management for ensuring high quality services to consumers and overall network reliability.
