Fundamentals of WANs and IP Routing

Multiple LANs or other WANs across a large geographical area connect via Wide Area Networks (WANs). Businesses can share data and communicate over long distances spanning across cities, countries, or even continents because of these networks. Forwarding packets between different networks using IP routing is a fundamental concept of WANs. This article will cover the fundamentals of WANs and IP routing, including different WAN technologies, routing protocols, and best practices for designing and implementing WAN solutions.

Types of WAN Technologies

Unique characteristics and features distinguish each type of WAN technology. Some of the most common types of WAN technologies include:

MPLS: Label-switching technology forwards packets between different networks. Although it can be complex to configure and manage, this technology provides high reliability and Quality of Service (QoS) capabilities.
Cellular: These are wireless connections that use mobile networks to connect to a WAN. Cellular connections are often used for remote locations or backup connections and can be less reliable than other WAN technologies.

Routing Protocols

IP routing is the process of forwarding packets between different networks, using a routing protocol to determine the best path for each packet. WAN environments use several routing protocols, such as:

A network administrator must evaluate carefully the network requirements and select the appropriate protocol as each routing protocol has its own strengths and weaknesses. Small networks with only a few routers may find RIP suitable, while larger networks with multiple paths and redundancy may be better suited for OSPF. BGP may be appropriate for ISP environments that require inter-AS routing capabilities.

Designing and Implementing WAN Solutions

Designing and implementing WAN solutions involves several crucial considerations, such as network topology, cost, security, and bandwidth requirements. One of the most significant factors that can impact performance and reliability is the network topology. There are several common WAN topologies, including:

Point-to-Point: A simple topology with a direct connection between two locations, using a leased line or other technology.
Hub-and-Spoke: A hub location connects to multiple spoke locations, such as branch offices or remote sites. A mesh-like topology that connects multiple locations, allowing for multiple paths and redundancy, is known as Multipoint.

When designing and implementing WAN solutions, other important considerations include bandwidth requirements, which will affect the selection of WAN technology and routing protocol, and security requirements, such as the use of Virtual Private Networks (VPNs) to encrypt traffic over the WAN. WAN solutions can be expensive to implement and maintain, making cost an important factor to consider.

Cisco's recent survey found that WAN optimization was one of the top networking priorities for businesses in 2020. Of the surveyed businesses, 83% are using WAN optimization technologies, with 54% using SD-WAN solutions to enhance network performance and reduce costs. Software-defined networking principles are used by SD-WAN, which is a newer WAN technology that simplifies WAN management and optimization.

As critical components of modern networking environments, WANs and IP routing are essential concepts for any network administrator to understand. By selecting the appropriate WAN technology and routing protocol, designing a suitable network topology, and implementing effective security measures, businesses can ensure reliable and efficient communication and data sharing over wide distances.