What function is performed by the border node in Cisco SD-Access?
Short answer
D Provide connectivity to traditional Layer 3 networks.
Question
Key Takeaways
The exam tests your ability to distinguish the roles of SD-Access fabric nodes; the common trap is confusing the border node with the edge node or control plane node.
In Cisco SD-Access, the border node provides Layer 3 connectivity between the fabric and external traditional networks. Community consensus unanimously confirms option D as the correct answer.
Common mistake: Option A is frequently chosen by mistake because it describes the function of the edge node, which connects endpoints to the fabric, not the border node.
Expert Analysis
Why the Answer Is Correct
The border node in Cisco SD-Access is specifically designed to interconnect the SD-Access fabric with external Layer 3 networks, such as legacy LANs, WANs, or the Internet. It performs route leaking between the fabric's virtual networks (VRFs) and external routing domains. As comment [1] and [2] correctly note, it routes traffic into and out of the fabric, ensuring communication with devices outside the fabric domain.
Why the Other Options Are Wrong
Option A describes the edge node, whose role is to connect users and devices (endpoints) into the fabric domain. Option B refers to the function of IP Device Tracking (IPDT) and DHCP services typically handled by the DNA Center or edge nodes managing IP pools. Option C describes the control plane node, which uses LISP to provide reachability and mapping information for fabric endpoints. Confusing these roles is the most common pitfall.
Community Comment Notes
All community comments unanimously agree on option D. Comment [1] provides a concise and accurate definition of the border node, while comment [2] elaborates on its dual role of routing traffic in and out of the fabric. Comment [3] links to the official Cisco SD-Access Design Guide, which is the authoritative reference for fabric node roles.
Official Reference
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html
This link opens the official vendor documentation in a new tab.
Exam Strategy
When answering SD-Access node role questions, create a quick mental mapping: Edge = endpoint onboarding, Border = external L3 connectivity, Control Plane = LISP mapping/reachability. This will help you eliminate distractors in under 30 seconds.
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 4 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 4
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teems5uk 👍 4 Answered DFabric border node: This fabric device (for example, core layer device) connects external Layer 3 networks to the SDA fabric
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chiacche 👍 1 Answered DFunction of Border Node in SD-Access: 1. Provides Layer 3 connectivity between the SD-Access fabric and external networks. 2. Routes traffic into and out of the fabric, ensuring communication between internal fabric devices and devices or services outside of the fabric.
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nj1999 👍 1https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html
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Mizuchan 👍 2 Answered DSeems correct
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