Why LTE is Called Flat Architecture?
Let me walk you through why LTE is often referred to as having a “flat architecture.” Understanding this concept is essential because it highlights how LTE differs from earlier generations of mobile networks, like 2G and 3G, and how it brings improvements in speed, capacity, and latency.
In previous network generations, such as 2G (GSM) and 3G (UMTS), the architecture was hierarchical, with multiple layers of network elements between the user equipment (UE) and the core network. These architectures had a clear division between different functional layers, each performing specific tasks. This hierarchical design introduced complexity, as signals had to pass through several layers before reaching their final destination, resulting in higher latency and slower data transfer speeds.
Now, LTE (Long-Term Evolution) revolutionized the mobile network by adopting a flat architecture. So, what makes it “flat”? The term “flat” refers to the simplification of the network structure, where fewer layers and less infrastructure are needed to support communication between the user equipment (your mobile phone) and the core network. This leads to a more efficient and faster data transmission process.
The main reason LTE is called flat is because it eliminates the need for several intermediary nodes found in previous generations. For example, in 2G and 3G networks, there were separate control planes and user planes, along with multiple nodes like the Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN) in 3G. These nodes would route the data through several steps before it reached its final destination, creating unnecessary delays.
In contrast, LTE simplifies this by integrating functions and reducing the number of network elements. The core network in LTE consists of the Evolved Packet Core (EPC), which includes a much smaller set of nodes compared to older networks. The key elements in the EPC are:
- MME (Mobility Management Entity): Responsible for managing signaling, security, and session setup.
- SGW (Serving Gateway): Handles data traffic between the user equipment and the core network.
- PGW (Packet Data Network Gateway): Manages IP address allocation and routing for user data.
These nodes work together in a simplified manner, reducing latency and improving overall network efficiency. Because of the flat architecture, LTE is able to handle higher data rates, faster handovers, and lower response times, which are essential for the high-speed, low-latency experience expected by users today.
To sum it up, LTE’s flat architecture is a key factor in its efficiency and performance. By minimizing the number of network elements and simplifying the connection between user equipment and the core network, LTE can provide faster, more reliable mobile services. This is a significant upgrade from older technologies and contributes to the overall improvement in user experience.