Editor's note: The Internet has made network traffic management more complex as consumer and business services are increasingly aggregated onto the same network, even though quality of service guarantees vary depending on the service and the customer. All telecom operators -- including traditional, cable and wireless – need to provide proactive traffic metering and management in the access network and to segregate premium and regular IP best-effort traffic in the "middle mile" aggregation network if they hope to increase average revenue per user(ARPU) and achieve a good return on their investment.
All packet-based services, including IP, multiplex traffic from many sources onto shared facilities. >
It is this multiplexing, which is often called "oversubscription," that makes packet services much more economical than traditional TDM services.
There's a downside, of course. Oversubscription means there's a risk that the total traffic presented at a given time might exceed transport resources, which will result in congestion, delay and packet loss.
Network traffic management -- especially in the "middle-mile" service aggregation infrastructure -- holds the key to balancing the quality of service (QoS) requirements of a service against the cost of transporting traffic for that service. The bottom line is that multiple services demand multiple traffic management policies.
Network traffic management techniques have been used to control congestion and provide specific quality of service since the first packet services were launched. In fact, it's fair to say that QoS is not possible without traffic management techniques, unless a network is engineered to never experience congestion. The traditional traffic management that operators offer business customers is to guarantee QoS described by a service-level agreement (SLA) that spells out the terms under which QoS will be obtained and guaranteed.
How the Internet changed network traffic management forever
As with many things, the Internet introduced new complexity to the traffic management picture for the following reasons:
- Consumer broadband traffic is typically the largest traffic source of all, and shifts in activity will dominate network behavior.
- While most consumer broadband is used to deliver only Internet service, many network operators are also using broadband access for delivering IPTV, VoIP and other premium offerings. Over time, these additional uses (with incremental revenue potential) are likely to grow.
- By nature, the Internet was designed for "best-effort" traffic delivery, but premium broadband applications require QoS, and some (like IPTV) require stringent QoS.
- Regulators are scrutinizing Internet service delivery to ensure that capacity is delivered in a non-discriminatory way, but the question of just what that means has yet to be answered and is likely to have a different answer depending on the regulatory jurisdiction.
- Broadband services for businesses and consumers are delivered through a variety of network facilities, from access to core networks, and each of these can have different oversubscription levels, traffic management policies, and even congestion risks.
The desire to maximize ARPU has led operators to provision both business and residential customers with an oversupply of access capacity to allow future service growth where technology permits. But in other service scenarios, access capacity may be constrained. Wireless and cable uplinks are two examples. Either situation may complicate traffic management -- wireless by increasing the potential load by increasing access speeds, and cable by demanding some mechanism for fairly sharing limited capacity among users.
Continued: Traffic management solutions for the access and aggregation "middle mile" networks