First, the obligatory conference summary. NFV celebrated its first birthday in Frankfurt last week, at the SDN & OpenFlow World Congress which occurred exactly a year after a group of telecom service providers announced the formation of the ETSI NFV ISG. Both from the wide range of conference presentations and from the solutions showcased by exhibitors, it was clear that tremendous progress has been made in addressing the complex issues that must be solved in order for deployments to be viable and cost-effective. In our booth, we were pleased to see strong interest in our accelerated Open vSwitch solution that’s optimized for SDN and NFV applications. We enjoyed Tom Nolle’s explanation of the benefits this provides and we also learned that we’d won a 2013 Excellence in SDN Award from TMC.
End of trip report. The conference has been summarized excellently in a variety of blogs, written by attendees who have done a great job of highlighting the most interesting points from such an extensive event.
For me, though, the presentation that I will remember longest is the one given by Tetsuya Nakamura, Senior Research Engineer at NTT DOCOMO and Assistant Manager with the ETSI NFV ISG.
In his presentation “Carriers' expectations and challenges for Network Virtualisation”, Nakamura-san outlined the impact on communications infrastructure caused by the 2011 earthquake in Eastern Japan. He explained how NTT DOCOMO has applied SDN technology to ensure that the most critical communications will suffer less impact in any future disasters: these communications are voice calls from people desperate to confirm the safety of family members.
NTT DOCOMO saw a 60x increase in attempted voice calls during this time. Obviously, when the priority is to confirm that a family member is OK, no-one cares about email or rich media, they want to talk to them.
NTT DOCOMO was able to connect only around 5% of the call attempts. Even as far away as Tokyo, the network was so congested that the vast majority of calls within Tokyo failed.
The net result: many millions of concerned people were unable to confirm the safety of their family members. At the same time, ironically, people were able to stream videos and access rich media pretty much as normal.
The problem, of course, was the static configuration of the network. Network capacity (bandwidth and equipment) was provisioned to handle normal volumes of voice, email and rich media traffic. In normal times, the goal for the network is to provide high-quality service at a reasonable price and resources are optimized for cost-efficiency. In a disaster scenario, however, the requirement is to support the most necessary (voice) communications, by applying a huge amount of resources not used for voice in normal periods.
As Nakamura-san stated in his slides, “Disaster-resilient mobile networks must support contradicting demand in normal periods and in the disaster period. To develop flexible mobile networks, the key issue is how to improve flexibility in control systems to allow reallocation of functions depending on the changing demands.”
Enter SDN. Since the disaster, NTT DOCOMO has implemented SDN to achieve dynamic resource allocation, ensuring the viability of their networks even in an emergency. This brings a massive improvement in the acceptance rate of voice calls immediately following a disaster.
A combination of the Service Resource Control Framework and Call/Service Control provide flexible control of system resources.
In a normal period, resources are mostly allocated to EPC functions, supporting email and rich media traffic. In response to a disaster, however, virtualization-aware control and management services are used to dynamically reallocate resources, scaling up the capacity for IMS-based voice traffic.
As illustrated in the diagram below, NTT DOCOMO expects these innovations to boost the call acceptance rate by 5x during a scenario such as the 2011 disaster. This is achieved not by increasing the network capacity (shown flat in the analysis), but by the SDN-based reallocation of resources.
NTT DOCOMO has built data centers in Tohoku and Yokosuka to evaluate and stress-test this architecture. They can emulate congestion in an area supporting 500,000 consumers, representing more than 700,000 calls per hour (196 calls per second). Before reallocation, the network can accept 125,000 calls per hour and this rises to 700,000 after reallocation, with the transition being accomplished in less than 30 minutes. Eventually, the trials will encompass additional sites and then the architecture will be deployed in the live network.
We all read and listen to a lot of SDN- and NFV-related stories where the outcome is measured in service velocity, CAPEX, OPEX and ARPU. Nakamura-san’s presentation was different. He talked about the anguish felt by real people, trying to contact family members in the aftermath of the kind disaster that most of us can only imagine. In this case, SDN technology will ensure that many more of those calls go through. Isn’t that the ultimate example of “end-user value” for the people of Japan?