High-Level Design Considerations
Considering the complexity of a majority of the networks out there today, they can be classified in a couple of categories, such as redundant and non-redundant. Typically, redundancy leads to increased complexity. Oftentimes, the simplest of networks do not plan for failures or outages and are commonly single-homed designs with multiple “single points of failure.” Networks can contain different aspects of redundancy. There can be redundant links, routers, and service providers when speaking strictly of the WAN portion of the environment. Table 1-1 lists some of the common techniques introduced when dealing with redundancy.
Table 1-1 Common Redundancy Techniques
Redundant Links |
Redundant Devices |
|---|---|
Administrative distance |
Redistribution |
Traffic engineering |
Loop prevention |
Preferred path selection |
Preferred path selection |
Prefix summarization |
Advanced filtering |
Filtering |
Having a visual of what some of these topologies look like is often helpful. Figure 1-3 showcases some of these various topologies and their associated redundancy types, putting into context how the network will need to be configured and managed to support these types of redundancy options.
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FIGURE 1.3 Topology-Based and Link Redundancy Options
Outside of the complexity associated with redundancy, there are many other aspects of the network that cause complexity within a network environment. Some of these aspects can include things such as securing the network, to shield it from malicious behavior; leveraging network segmentation, to keep traffic types separate for compliance or governance reasons; and even implementing quality of service (QoS), to ensure application performance and increase users’ quality of experience. What further complicates the network is having to manually configure these options. The networks of today are too rigid, and things need to evolve. The industry is moving from the era of connectivity-centric network delivery models to an era of digital transformation. A shift is required to transition to a digital transformation model. The shift is from hardware and device-centric options to open, extensible, software-driven, programmable and cloud-enabled solutions. Figure 1-4 depicts the transition in a simple summary. Intent-based networking (IBN) is taking the industry by storm. The concept revolves around signifying the intent of the business and automatically translating that intent into the appropriate corresponding networking tasks—relying more on automation to handle the day-to-day operational tasks and getting back time to focus on how to make the network provide value to the business. This is delivered through policy-driven, automated, and self-optimizing capabilities. This provides closed-loop, automated service assurance that will empower network operations staff to transition from a reactive nature to a more proactive and predictive approach. Freeing up more of the operations staff’s time will hopefully allow them to focus on more strategic initiatives within the business.
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FIGURE 1.4 Digital Transformation Transition