Improving fixed broadband customer experience by keeping the noise down

An Asian incumbent fixed network operator was receiving many complaints about its broadband service. The poor customer experience was so widespread that the issues were highlighted in the national press on a number of occasions. These issues were having a significant detrimental impact on the network operator's business, because of high churn rates and reduced acquisition of new broadband subscribers. However, more worryingly, the issues were tainting the operator's overall reputation as the national incumbent fixed-line operator with the government as well as with customers.

Analysys Mason was engaged to undertake a comprehensive network audit on the operator's copper-based broadband network and operations, in order to identify the root causes of the broadband service performance issues, implement quick fixes and to make recommendations to further improve the overall quality of the broadband services. The scope of the audit addressed the end-to-end delivery of the broadband services and their management from customer premises equipment, through to international website hosts via the copper access, metro and core networks, domain name servers (DNSs), deep packet inspection (DPI) router policies and international connectivity.

We undertook a detailed analysis of the network and operations utilising two complementary methods.

• A desktop review assessing the network design and architecture, network dimensioning and utilisation, bandwidth management strategy, international connectivity and operational processes.
• A sample of actual measurements of the network performance using network probes placed at the customer premises and in strategic locations in the network.

The network design review aimed to ensure that the network was designed to be capable of delivering the services that were being offered to an expected level of quality. We determined that from a network design point of view, the network was theoretically capable of delivering the expected broadband services, and actually had significant spare capacity. This implied that the issues were caused by poor network configuration and/or management.

Using Nova Incepta's NovaQX network performance measurement system, we initially detected several service performance issues throughout the network. However, on further investigation we discovered that the root cause of many of the performance issues was the high level of noise on the copper access lines. Once the reasons behind the noisy lines were identified and the issues resolved, the end-to-end performance of the broadband service improved significantly throughout the network and greatly improved the overall customer experience.

The audit revealed that the digital subscriber line access multiplexers (DSLAMs) connecting the customers to the network via the copper lines were sub-optimally configured. The configured target signal to noise ratio (SNR) was set too low, which was leading to unstable and highly noisy lines. The instability and resultant noise resulted in high packet loss. The packet loss meant that end users experienced an intermittent service because their modems had to re-synchronise frequently. In addition to the direct impact on service, the observed packet loss had a number of secondary impacts in the network that further degraded the quality of service, including:

• high DNS lookup failure rate because of corrupted packets
• high DNS response time because of packet retransmission
• high PING response times because of TCP retransmissions.

We identified the reconfiguration of the DSLAMs as a quick win and facilitated their reconfiguration during the audit. We then repeated the performance measurements to prove that this solution had improved the broadband service, which it had. In order to make further improvements we recommended that the configuration of each line be customised to optimise performance. Figure 1 shows the results of the DSLAM reconfigurations of 15 000 active lines.

Figure 1: Improvement in ADSL line stability [Source: Analysys Mason, 2013]

Figure 1 shows that only around 7000 lines from the 15 000 that we measured were stable. After the customised second reconfiguration, more than 12 000 lines became stable, therefore significantly improving broadband performance at little cost to the operator.

We also assessed all operational processes associated with the resolution of faults with the objective of decreasing the fault backlog and improving the overall fault resolution times.

We provided 24 recommendations and described their impact and a high-level implementation plan. The recommendations covered quick wins, the network design and configuration, international connectivity strategy, operational strategy and training. Some of the quick-win recommendations were implemented before the completion of the audit and the stability of 70% of the operator's broadband lines improved within one month. We also recommended an alternative operational process, which led to 70% of customer reported faults being fixed within a single day and a significant reduction in reported repeat faults.

As a result of our recommendations, an article in the main national newspaper acknowledged the vast improvement in the network quality, enabling the operator to start to regain trust of its customers and to re-build its brand.

Analysys Mason offers network audit and technical due diligence services to network operators and other stakeholders to provide them with network and operational quality assurance or to help them resolve technical issues, minimise costs or build robust investment business cases.