What is IP Routing?

IP routing applies routing methodologies to IP networks, which utilize the internet protocol suite for communication. An IP router, or network node, determines the optimal path for a network packet to travel from its source to its destination. While routers connect physically via fiber optics, copper cabling, or wireless media, IP routing fundamentally involves computing a route and transporting digital bits across the network.

IP's role in the OSI model

The network industry uses the OSI stack to conceptualize the seven layers of communication.

• Physical layer (L1): Comprises physical media like copper cable.
• Data link layer (L2): Establishes and terminates links between nodes (e.g., ethernet). IP operates at the network layer (L3), assuming L1 and L2 are functional. The router's primary job is to determine the route and forwarding path for data bits.

The diverse data carried by IP

When we refer to 'data' in this context, we generally mean user data – any digital information from various applications. This can include:

• Email
• Video conferencing
• Voice applications
• Control signals for electrical transmission networks
• Instructions for autonomous mining trucks

Millions of applications currently rely on IP to move their specific data across networks.

How IP handles data: encapsulation

IP performs two key functions with user application data:

• Encapsulation: It packages the data into packets.
• Packet structure: Each packet consists of a 'payload' (the user data) and a header. The header contains essential information, such as the source and destination addresses, similar to a shipping label, along with other details related to the payload.

Routing protocols and network control

Routing protocols dynamically configure packet-forwarding tables to direct IP packets to the next available IP router or network node on their path to the destination. To coordinate these actions, IP routers communicate via the control plane.

• Control plane: Performs the routing decisions.
• Data plane: Executes the forwarding of packets.

The evolution of IP: from "best-effort" to QoS

Initially, IP was designed as a "best-effort" protocol, where Quality of Service (QoS) was not a critical consideration. This made it ideal for applications tolerant of latency, such as email. However, it was less suitable for:

• Latency-sensitive applications: Like telephone conversations, where delays degrade the experience.
• Mission-critical applications: Such as autonomous vehicles or electrical relays, which cannot safely tolerate latency or delay.

Why QoS is now critical

The "best-effort" approach was sufficient when internet traffic was less demanding. However, with the rise of real-time and interactive applications, QoS has become indispensable. Services now require guaranteed QoS. This necessity has driven the development of QoS mechanisms and protocols, enabling IP networks to meet the demanding requirements of the multimedia and cloud services era.

The future of IP networks: agility and scale

As services and applications continue to expand, the reliance on IP networks will only grow. With more applications sharing the same infrastructure and increasingly delivered via scalable clouds, networks must become significantly more agile, scalable, and resilient.

A key focus for IP networks is the ongoing shift towards mission-critical and business-critical vertical applications. Access will evolve through wireless and wireline networks, connecting to powerful IP edge routers. These routers will link edge clouds and central clouds using high-speed data center interconnection services.

This evolution demands that IP routers become faster, handling data center interconnection services at 400 and 800 Gbps, a trend already underway. This requires highly specialized network processors, such as the Nokia FP5, to analyze incoming packets, manage services, and add encryption at very high line speeds while simultaneously reducing power consumption.

Regardless of future advancements, IP routing remains a foundational technology.