Very Small Site Design Considerations – SD-Access Design

By | 08/20/2024

In very small sites, high availability and site survivability requirements are not common. Shared services are present in all reference designs for DHCP, DNS, WLC, and ISE. These services can be deployed in a remote data center and connected to the fabric through a fusion router, or they can be deployed locally with direct connections. High availability can be deployed in the design through StackWise technology with stackable switches or with multiple supervisors if chassis-based switches are used. WLCs can be attached to the fabric, or an embedded Catalyst 9800 WLC can be used running on a Catalyst 9300/9400/9500.

Table 10-2 shows reference guidelines for very small sites.

Table 10-2 SD-Access Very Small Site Guidelines

SD-Access Component DescriptionSize
EndpointsUp to 2000
IP poolsUp to 8
Virtual networksUp to 8
Border nodesUp to 1
Control plane nodesUp to 1
Edge nodesUp to 1
Wireless LAN controllersUp to 1
Access pointsUp to 100
Small Site Design Considerations

High availability with small sites typically colocates border and control plane node functions on a pair of collapsed core switches. Multiple link connections should be used between the core switches for link redundancy and added resiliency. Since the endpoint counts are usually higher with small sites than with very small sites, embedded WLCs are not recommended unless there are fewer than 200 APs and 4000 endpoints. The higher endpoint and access point counts use physical WLCs deployed with high availability connected to the fabric. The WLCs should be connected using a service switch directly to the border nodes or attached to the fusion router locally at the fabric site.

Table 10-3 shows reference guidelines for small sites.

Table 10-3 SD-Access Small Site Guidelines

SD-Access Component DescriptionSize
EndpointsUp to 10,000
IP poolsUp to 100
Virtual networksUp to 32
Border nodesUp to 2
Control plane nodesUp to 2
Edge nodesUp to 25
Wireless LAN controllersUp to 2
Access pointsUp to 200
Medium Site Design Considerations

In medium sites, dedicated border and control plane nodes are used for high availability. Inter-Switch Links should be used between the core switches for link redundancy and added resiliency. The control plane nodes would also connect to the core switches. Embedded WLCs are not used in medium-sized sites due to the larger endpoint counts. Because these sites are larger, physical WLCs are needed and are typically deployed in a high availability pair for redundancy. The WLCs should be connected using a service switch directly to the border nodes or attached to the fusion router locally at the fabric site.

Table 10-4 shows reference guidelines for medium sites.

Table 10-4 SD-Access Medium Site Guidelines

SD-Access Component DescriptionSize
EndpointsUp to 25,000
IP poolsUp to 300
Virtual networksUp to 64
Border nodesUp to 2
Control plane nodesUp to 4
Edge nodesUp to 250
Wireless LAN controllersUp to 2
Access pointsUp to 1000

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