Internet Service Provider

Description

An Internet Service Provider (ISP) is a company or organization that offers services for accessing, using, or participating in the internet. In the context of 3GPP, ISPs are external entities that mobile network operators (MNOs) interconnect with to provide data services to subscribers. This interconnection enables users to access internet-based applications, websites, and cloud services through their mobile devices. 3GPP specifications address ISP interactions in areas like quality of service (QoS), policy control, charging, and security, ensuring that mobile networks can seamlessly integrate with the broader internet ecosystem.

Architecturally, ISPs connect to 3GPP networks via interfaces such as Gi (in 2G/3G) or SGi (in 4G/5G), which link the packet data network gateway (PGW) or user plane function (UPF) to external packet data networks (PDNs). The 3GPP core network, through components like the policy and charging rules function (PCRF) or policy control function (PCF), enforces policies that may be influenced by agreements with ISPs, such as bandwidth throttling or prioritized traffic for specific services. Billing systems also interact with ISPs to support scenarios like sponsored data, where an ISP covers the cost of data usage for certain content.

In operation, when a mobile user requests internet access, the 3GPP network establishes a data session that routes traffic through the ISP's network. Key processes include IP address allocation (often via DHCP or from the ISP's pool), authentication and authorization (possibly involving the ISP's servers), and traffic management based on service level agreements (SLAs). 3GPP standards ensure that these processes are standardized to prevent fragmentation and support roaming. For example, specifications like TS 23.060 (GPRS) and TS 23.401 (EPS) detail how data sessions are managed with external networks, including ISPs, to provide consistent user experiences across different operators and regions.

Purpose & Motivation

The purpose of considering ISPs within 3GPP standards is to define how mobile networks interconnect with external internet infrastructures, enabling comprehensive data services for subscribers. ISPs solve the problem of extending mobile network reach beyond operator-controlled services to the global internet, allowing users to access a vast array of applications and content. This interconnection addresses limitations of early mobile networks, which were often walled gardens with limited external access, by facilitating open internet connectivity.

Historically, as mobile networks evolved from voice-centric systems (e.g., GSM) to packet-based data services (e.g., GPRS in Release 99), the need for standardized ISP interactions became critical. Without clear standards, interoperability issues could arise, leading to poor service quality or complex billing arrangements. 3GPP specifications provide frameworks for QoS differentiation, where ISPs and MNOs can agree on traffic priorities, and for charging mechanisms, such as volume-based or time-based billing, that reflect ISP partnerships.

The motivation for integrating ISP considerations into 3GPP includes supporting business models like zero-rating (where specific content does not count against data caps) and ensuring secure, efficient data routing. As mobile broadband has grown, ISPs have become key partners in delivering over-the-top (OTT) services, and 3GPP standards help manage these relationships technically. This ensures that mobile networks remain competitive and flexible in an internet-driven world, balancing operator control with open access.