Designing a LAN for the campus use case is not a one-design-fits-all proposition. The scale of campus LAN can be as simple as a single switch and wireless AP at a small remote site or a large, distributed, multi-building complex with high-density wired port and wireless requirements. The deployment may require very high availability for the services offered by the network, with a low tolerance for risk, or there may be tolerance for fix-on-failure approach with extended service outages for a limited number of users considered acceptable. Platform choices for these deployments are often driven by needs for network capacity, the device and network capabilities offered, and the need to meet any compliance requirements that are important to the organization.
* Traditional Access - Dedicated Distribution and Access Layers (L2 or L3). You impose most of the campus wired LAN design complexity when aggregating groups of access switches by interconnecting the access layers to the distribution layers. If devices connecting to the access layer have a requirement to communicate with a Layer 2 logical adjacency and those connections cover multiple physical wiring closets connected to a distribution layer, then it is possible to adapt the traditional multilayer campus design to address the Layer 2 adjacency needs. However, the traditional designs drive more complex configurations with additional protocols that must be kept consistent across multiple devices.
* Simplified Access – Virtualized StackWise Access & StackWise Virtual Distribution. To improve the design, there are preferred alternatives that make the deployment easier to manage and less prone to mistakes, while enhancing overall network performance. Such alternatives include the simplified distribution layer using options such as a switch stack or a StackWise Virtual system, and the simplified access layer using a switch stack with StackWise technology. Both make deployment and troubleshooting much easier for support staff.
* Cisco Software Defined Access – Campus Fabric and Automation of the Distribution & Access Layers. A design alternative is available for organizations that either don't have the need to extend Layer 2 connectivity across an access-to-aggregation boundary or have other means of implementing this functionality, such as when using fabric technology for campus designs—an integral part of Cisco SD-Access. The alternative to the Layer 2 designs is to extend Layer 3 connectivity to the access layer. The implementation of a well-designed Layer 3 access network ensures consistent, configuration, performance, scalability, and high availability of the network versus the traditional multilayer campus design.
