Telecommunications

October 5, 2006
Broadening the Broadband QoS

Geetanjali Babbar

NEW DELHI -- Broadband is the buzzword for today, and so is the quality of service for broadband networks. According to industry experts, the global market for broadband services is expected to grow to US $80 billion in the next five years, with an CAGR of 33 percent. For broadband to reach its expected and deserving place, the industry need to take care of the an important factor -- QoS.

QoS is a major issue on broadband networks everywhere. Even if service providers have enough bandwidth, they find it difficult to ensure quality. The challenge is to optimise network and enhance user experience.

QoS refers to the ability to provide and maintain certain quantifiable performance levels on a shared network. It addresses the techniques and methods by which network elements and services are monitored, traffic is prioritised, and performance degradation causes are isolated and visualised.

It is important to state that quality of broadband service depends not only on technical issues, but also on other aspects of quality such as price, perception, and customer service. In this story, we are focusing mainly on the technical aspect of QoS.

QoS is the idea that transmission rates, error rates, and other characteristics can be measured, improved, and, to some extent, guaranteed in advance. It is of particular concern for the continuous transmission of high-bandwidth video and multimedia information. Transmitting this kind of content dependably is difficult in public networks using ordinary "best effort" protocols.

Internet and broadband access are widely recognised as catalysts for economic and social development of a country. Availability of broadband services at affordable price levels will contribute to higher GDP growth rates, provide for a larger and more qualified labor force, and make that labor pool more efficient.

To reap the benefits of broadband the government needs to take decisive steps with respect to standards, regulations, business models, consumer value proposition, distribution, etc. While TRAI has taken a lead in defining the base service as 256Kbps and above, the QoS has not been properly defined. While 256Kbps could be the access, the kind of a QoS the users get is not defined.

Broadband QoS by itself is only one brick in the wall of the customers’ overall quality of experience and their perception of the service. Providers require fine-tuning and co-ordination of quality mechanisms in all network layers – from access through aggregation to the core – and even outside their network domain to meet with demanding service level requirements.

Measuring Broadband QoS

First of all, broadband as a service does not have the QoS associated with a leased circuit or a VPN (MPLS). The service delivery is best effort based. While there are no strict service guarantees associated with the service, one needs to make a clear distinction between the bit speed available and the throughput. While the bit speed would always match what is being quoted, the throughput is the one that varies with load on the network. A broadband network, even though does not commit a stringent service level agreement (SLA), should atleast confirm to a throughput that would be available more than 80 percent of the time. This could be defined as a “Typical” speed for a want of a better term. While it is obvious that under heavy loaded conditions the “Typical” speed would not be met, the service provider should design the network in such a way that statistically atleast 80 percent of the time the network meets this speed.

Three major performance collection approaches are available to build a comprehensive picture of QoS:

• Active Monitoring: Utilising dedicated probes that proactively monitor network quality, voice quality and video quality. This technique also helps achieve a better understanding of QoS from the consumer’s perspective, leading to an efficient way of prioritising and handling problems;
• Passive Monitoring: Measuring all relevant key performance indicators in the network as created and reported by network elements, such as data rates, queues and buffers, etc.
• Traffic Monitoring: Collecting traffic related data such as CDRs or IPDRs and generate traffic-based counters that reflect end-to-end quality of service levels.

The collected data can then be enhanced with external data resources at the mediation layer of the OSS, manipulated to produce computed counters, such as network or service reliability, and aggregated at the performance management layer of the OSS. Eventually, performance measurements can be easily accessed by service providers and customers via reporting tools and portals.

Monitoring QoS

It is important to state that broadband QoS does not deal only with the access layer of the network, but involves the tuning of QoS throughout the service provider network, including aggregation and core layers. Each layer applies different QoS mechanisms, and they all have to be co-ordinated and tuned together to provide a seamless QoS, from the core to the customer home or business network.

Monitoring QoS involves:

• Providing real-time monitoring both for network level indications (such as network delay, jitter and packet loss) and real-time application level indicators;
• Utilising root cause diagnostics to quickly isolate service degradation before customers are impacted; and
• Assuring service levels are being met, tracking threshold crosses to optimise network efficiency, and verifying that SLAs are not compromised.

Key Concerns

From a provider's point of view, NGNs are becoming very complex. The ability of the service provider to identify service impairments in real time is becoming harder due to this complexity, and due to the limited monitoring tools that provide visibility to the services. Lack of standards in the industry, especially regarding emerging application services, causes service providers to carefully and slowly apply quality of service mechanisms that can enforce the necessary level of quality.

QoS has become a great challenge to service providers where customers have high expectations based on their acquired experience in the broadband market. Customers have expressed concerns about actual performance of services they received as opposed to the characteristics of the services promised by the providers. Furthermore, research shows that Broadband users appear increasingly willing to switch providers ­- consequently, service providers struggle to meet customers' expectations in order to reduce churn.

Encouraging Further Penetration

Broadband penetration depends on the penetration of PCs, availability of content/ killer applications and the ability of a service provider to provide a cost-effective service that is afforded by the population that is being served. While the first issue is being addressed by providing attractive financing schemes, efforts in solving the second are being made by both public and private sector. The third issue is rather complex to address. Most often it becomes a vicious circle if the subscriber base is low because of the ability of the subscriber to pay. The only viable alternative in this scenario is deployment of wireless technology.

Commenting on the ways to increase broadband penetration, K.Krishna, senior director, marketing, Hughes Communication, said: "Out of the wireless options available, satellite has a distinct advantage of ubiquitous coverage."

Today, Hughes has a worldwide installed base of over 800,000 satellite broadband terminals in geographic areas where service providers find it difficult to justify investment in laying terrestrial infrastructure. Hughes is a pioneer in the satellite broadband arena and has over the years constantly strived to a terrestrial comparable offering to the subscriber. This has involved a rigor and a deep focus on R&D. In India, Hughes is deploying its broadband terminals and is providing service to a variety of subscribers. Hughes today has partnered with both the government and private entities to help in the penetration of broadband. Projects like Edusat, CIC initiative in the North East and ITC E-Choupal are good example of its initiatives. Today, Hughes serves the consumer through its broadband kiosk project called HughesNet Fusion.

Taking the issue further, Avner Amran, vice president, marketing and business development, TTI Telecom, said: "To encourage further take up of broadband, providers need to ensure that the QoS does not deteriorate as the number of subscribers increases, diversity of services with different quality requirements grows, and network infrastructure adopts new technologies."

Three key quality factors determine how customers recognise the value of broadband services:

• Contention Ratio: It refers to the maximum number of users who may be sharing bandwidth at same time. It is important for consumers that speed does not deteriorate as the service reaches the maximum;
• Moving from Infrastructure QoS to Individual QoE: Each customer might have different service bundle with unique requirements and network engineering that should be flexible enough to adjust and fine tune resources accordingly;
• Isolating Service Impairments: This is becoming a crucial factor where broadband customers appear increasingly willing to switch providers; and
• Allowing nomadic customers to maintain SLAs on different broadband access networks.

Changes in Usage Patterns

Broadband networks that are in operation today, measure and provision bandwidth on statistical models.They use parameters like concurrency and “Typical” speed to build a relation between the number of users being served and the bandwidth that needs to get provisioned. While, these assumptions are fair for most of the applications, some of the new generation applications like Web conference, VoIP, online streaming hold the bandwidth for a considerable amount of time and the concurrency of the network increases quite drastically.

Most of the service providers do not have mechanisms to detect this abuse on the network and let the entire community of users suffer. "Hughes today employs a technique called 'Fair Access Policy' to analyse the network usage by different customers and makes sure the network is fair to a large customer base and not a selected few who run bandwidth heavy applications," added K.Krishna.

The shift from standard Internet services to next-generation services such as TV and voice services, online gaming, and video and music uploading and downloading have an enormous effect on the demands for shared bandwidth, and therefore, affect customer perceptions of the QoS experienced.

Providers understand that they have to compete regarding service quality, not just for price alone. They also understand that assuring infrastructure and network quality is not enough – they need to move towards assuring the quality of individual services and each element of the service, or risk losing the entire bundle to their competitors.

Data Rate Performance

Market research show that data rate of broadband services is an important factor in determining consumer satisfaction. Customer expectations in that area are closely related to the service trends and offerings available in the local market. To be able to provide next-generation application services such as standard Internet access, VoIP, music and video clip uploads and broadcast TV streaming services, customers require today data rates starting at connections of 1Mbps to 2Mbps and growing toward connections of 20Mbps.

"We expect an increase of that requirement in the near future when consolidated bundled services mature in the market. For example, a typical bundled service including HDTV (20Mbps per stream, two per household), online gaming (2Mbps to 20Mbps), VoIP (0.3Mbps, two per household) and standard data transfer (Emails, file sharing 10Mbps) will require anything from 50Mbps up to 90Mbps," added Avner Amran.