Introduction To Routers
Welcome to the Routers Section
In this section, we dive into the core concepts of routers: their purpose, how they function, and their crucial role in networking. Before proceeding, we recommend having a basic understanding of the OSI model and how data traverses a network. If these topics are unfamiliar, review our networking section for foundational knowledge on the OSI model and protocols.
Purpose and Function of Routers
Routers play an indispensable role in modern networks. Their primary function is to route data between different networks, whether within an organization or to external connections like the Internet. As most networks today require interconnectivity, routers are now ubiquitous in both personal and enterprise environments.
Example Use Case:
Consider a business with offices in Sydney and Melbourne. To link these two locations, a leased line connects the sites, with routers at each end. These routers direct the necessary data traffic between the offices while filtering out unnecessary traffic, preserving bandwidth and reducing costs.
Types of Routers
Routers are broadly categorized into:
- Hardware Routers
- Software Routers
Hardware Routers
These are dedicated devices designed specifically for routing. They come pre-installed with software developed by manufacturers like Cisco, providing high-speed and reliable performance. Hardware routers are commonly used in enterprise environments due to their specialized capabilities. Over time, their prices have become increasingly affordable.
Example:
The Cisco 2900 series routers offer advanced functionality beyond basic routing, such as enhanced security and scalability.
Software Routers
Software routers are servers, such as those running Windows, Linux, or Novell NetWare, that can perform routing functions. These are often used for Internet gateways or firewalls. While software routers may mimic hardware router functions, they lack the dedicated hardware required for specialized WAN connections (e.g., ISDN, Frame Relay).
Comparison:
- Hardware routers are optimized for routing tasks and include built-in components for connecting to WAN links.
- Software routers, on the other hand, require additional network cards or expensive interface adapters to achieve similar functionality.
Routers in Action
Routers act as gateways, connecting local networks (LANs) to external networks. For example, a router in a home or office LAN directs traffic to the Internet, ensuring data packets reach their intended destinations.
Illustration:
- Workstations within a LAN see the router as the “default gateway.”
- Any traffic destined for external networks is sent to the router, which uses routing protocols to determine the best path to its destination.
In multi-office setups, routers can connect through WAN protocols like ISDN, enabling seamless communication between geographically distant locations.
Key Features of Routers
- Operate at Layer 3 (Network Layer): Routers make forwarding decisions based on IP addresses.
- Do Not Propagate Broadcasts: Routers block unnecessary broadcast traffic unless explicitly programmed otherwise.
- Run Dedicated Operating Systems: Enterprise-class routers operate on specialized OS platforms, such as Cisco IOS.
- Utilize Routing Protocols: Routers communicate with one another using routing protocols to exchange network topology information.
Looking Ahead
This introduction sets the stage for deeper exploration of routers, particularly Cisco routers—the industry leaders. Future articles will delve into their advanced features, configurations, and why they remain the preferred choice for professionals worldwide.
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