GlossaryJanuary 2, 2023

What is a Core Network?

The core network (also known as the “backbone network”) is the heart of a communication network, and ensures the efficient and reliable delivery of traffic between main network nodes.

The core network provides connectivity and routing services between different parts of the network and controls the flow of traffic between these parts. For example, it connects different regions or countries and routes traffic to external networks, such as the Internet and cloud services.

The core network is designed to be very fast, reliable, scalable, and secure, and is perceived to be the most critical part of a communication network.

The core network is part of the three layers of network architecture:

  • Access layer: the first layer of the network that end users connect to and provides access to the network for all devices (computers, phones, IoT, etc.).
  • Distribution layer (also known as the “aggregation layer”): the layer that connects the access layer to the core layer and provides such network services as routing and traffic management.
  • Core network: the layer at the center and the most important layer in a three layer network architecture. As described, the core network provides connectivity and routing services between different parts of the network.

Main Responsibilities of Core Networks

  • Routing traffic: as mentioned above, the core network is mainly for routing traffic between different parts of the network. The core network typically uses a variety of networking technologies and dynamic protocols to provide improved connectivity and routing, for example, OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol).
  • Providing high-capacity, high-speed links: to connect and provide the necessary bandwidth to carry traffic through the network, the core network typically utilizes high-capacity, high-speed links, such as fiber optic cables.
    Using Quality of Service (QoS): the core network may also use Quality of Service (QoS) protocols to prioritize and control the flow of traffic through the network. For example, Multi-Protocol Label Switching (MPLS), Resource Reservation Protocol (RSVP), and to some extent also Software-Defined WAN (SD-WAN).
  • Ensuring reliability: The core network is typically designed to be highly reliable and scalable, as it plays a critical role in forwarding traffic. Reliability is ensured by implementing redundant components and protocols, such as high availability (HA) and load balancing, minimizing outages or failures and distributing traffic evenly across multiple servers or devices, improving reliability and availability.
  • Allowing Scalability: security is also important, as the core network must be able to accommodate the exponential growing traffic demands of the network. Solutions like the Distributed Disaggregated Chassis (DDC) can help with scalability along with efficient network segmentation, helping to reduce the impact of failures and allowing for easier network scaling.
  • Applying Security: Often, cyber-attacks target the core network, making security a top priority. In order to protect against these threats, core networks typically use firewalls, DDoS protection, and other intrusion prevention measures.
The Three layer Architecture
The Three layer Architecture

The Future of Core Networks

The economic framework of the current networking infrastructure put service providers in a position where they are losing revenue to hyperscalers and internet companies leveraging OTT services and extracting key monetization tools from service providers.

Key emerging technologies like 5G, IoT, artificial intelligence, and machine learning (ML) are expected to push the need for low latency, edge computing, and distributed approaches from service providers. As a result, service providers will likely adopt virtualized networking solutions to maintain flexibility, scalability, and cost efficiency.

It is most likely that core networks will be a part of this evolution serving at the heart of every network.