The growth of mobile data traffic over the last few years and projected for the near future is breathtaking (Figure 1), following a curve similar to that of the fixed internet in the 1990s. The latest Cisco Visual Networking Index (VNI) estimates that mobile data traffic grew by a factor of 2.6 during 2010, and the index forecasts a 26-fold increase over the next five years. At the end of that period, growth may decelerate as traffic generated by individual subscribers stabilizes, yet it should remain strong because the total number of subscribers will keep increasing.
Most of the discussion has focused on the overall increase in data volume and on the network wide tools available to meet the new level of demand. As a result, most of the action has been limited to introducing traffic caps or diverting traffic to Wi-Fi. Wi-Fi off-load has been a great boon to mobile operators. However, in the long term and as it is managed today, Wi-Fi off-load alone will not be able to shoulder the expected increase in data traffic.
Caps are more problematic. Generous caps can address abusive usage, but do not significantly affect legitimate use. Restrictive caps may generate resentment among subscribers, especially those used to unlimited internet plans, and risk dampening demand and use of mobile services at a critical phase in market growth. Perhaps even more importantly, restrictive traffic caps are ineffective at coping with data growth, because they target any type of data usage, regardless of time, location, or application, whereas operators need to selectively control the traffic going through the high-pressure points in their networks, where base stations are at or near capacity. Traffic elsewhere costs the mobile operators nothing. Even worse, it is quite possible that traffic caps have a stronger impact on off-peak usage, as subscribers are likely to engage in less urgent or valuable activities at that time—the type of activities that would be eliminated first if subscribers need to curb their data usage.
The inadequacy of traffic caps stems from the fact that growth in data traffic is not uniform across the network, or across subscribers. Instead, narrowly targeted solutions are required in different environments to address the specific characteristics of data traffic.
To determine which solutions are needed—and when and where—to cope with increasing traffic loads, we need to take a closer look at the distribution of traffic growth and where pressure points are within the overall network. We do this in the following pages by examining seven factors, each with specific traffic distribution dynamics, and the impact they will have on network traffic requirements. The analysis of the best suited solutions to address the challenges that these factors present is the topic of a subsequent report by Senza Fili Consulting.