What Is a Core Router?

A core router is a high-capacity network router designed to forward traffic at the highest speed possible. It’s positioned at the network core (aka backbone) and operates as a central hub that interconnects all other internal network segments. Although the core network does connect to external networks, the core routers themselves focus on the internal routing of data packets. Core routers usually prioritize high speed, massive capacity, and reliability.

Why do service providers need core routers?

Core routers form the backbone of any large network, ensuring that data is transmitted rapidly and efficiently across all internal network segments.

Key characteristics and requirements of core routers include:

• High-speed packet forwarding: Core routers are built to forward data packets at high speeds, using the latest and fastest protocols and interfaces available to move information as quickly as possible.
• High capacity and future growth: Core routers are designed to support massive amounts of data traffic and any future scalability requirements of the network.
• High availability: Acting as the backbone of the network, core routers must demonstrate high reliability and resiliency as they play a crucial role in maintaining overall network performance.
• Sophisticated routing protocols and policies: Core routers use sophisticated routing protocols and policies, such as ECMP and SR-MPLS, to efficiently move packets across the network.

Evolution of core routers

Nothing stands still and core routers are no different.

In the last 10 years, core routers have changed dramatically in the following aspects:

• Capacity: Over the past decade, we’ve witnessed exponential growth in core router capacity. While ten years ago they managed tens of terabits per second, today’s routers can handle hundreds of terabits per second. For example, AT&T’s core network powered by DriveNets Network Cloud handles 740 petabytes of traffic per day.
• Sustainability: Reducing power consumption and carbon footprint are becoming top priorities for all service providers (SPs), especially those in Europe. As a result, core router design has shifted to emphasize hardware reusability, creating a circular economy to extend product lifecycles.
• Distributed approach: With emerging technologies like 5G and AI, and the increasing need for more direct internet access, core routers are transitioning towards new distributed architectures for better performance and lower latency. We’re seeing a shift towards regional core networks (metro cores) that deliver superior performance and lower latency by optimizing interconnection and providing more direct breakout paths to the internet and cloud services.
• Disaggregation: Service providers have increasingly become advocates for disaggregation as it grants them greater technological flexibility. This approach avoids vendor lock-in, opening the door to a wider range of vendors, solutions and cutting-edge technologies. As a result, monolithic core routers are no longer the primary choice of service providers. Leading SPs such as Orange, AT&T, Vodafone, Comcast, Tata, KDDI, and others already are taking advantage of disaggregation and reinventing their network architectures.
• Automation and intelligence: Managing large-scale networks is a significant operational burden. Consequently, there’s been a major push towards automating network operations and
• integrating artificial intelligence into core routers. Through advanced traffic engineering techniques (like segment routing and ECMP) and AI capabilities, core routers can now predict and respond to traffic pattern changes, automatically reroute traffic to avoid congestion, and identify and mitigate malfunctions in real time.

Core routers and DriveNets

The DriveNets Network Cloud solution enables SPs to build routers of any type or size required using the same software and hardware across all network domains. DriveNets Network Cloud breaks down traditional monolithic routers into modular building blocks and turns the physical hardware into a shared resource supporting any network function, from core to edge.

DriveNets software can utilize efficiently any underlying hardware resource – including physical interfaces, network processing units (NPUs), central processing units (CPUs), ternary content addressable memories (TCAMs) and more – to deliver optimal performance tailored to specific use cases. The scale of routers can vary from a standalone 2.4T unit to a vast 819Tbps Distributed Disaggregated Chassis (DDC) cluster consisting of dozens of white boxes operating collectively as a single router.

DriveNets is behind the world’s largest software-centric core network at AT&T, and has since implemented large-scale networks in Europe, Japan, India, and North America.

Conclusion

In summary, core routers are the heart of any modern networking architecture, providing the critical speed, reliability, and capacity necessary to manage large-scale networks effectively. Acting as the ultimate traffic director, they efficiently facilitate the transfer of large amounts of data between various networks, ensuring seamless connectivity.

Today, service providers are exploring innovative ways to build their networks. One innovative approach includes the distribution of the core network into several smaller metro cores rather than centralizing them. This method not only enhances overall network performance but also significantly improves resilience and scalability. Furthermore, it allows for greater flexibility in supporting the rapid deployment of new, emerging services and adapting to changing market demands. By adopting such forward-thinking practices, SPs are better positioned to meet the growing expectations for high-quality, uninterrupted network performance.