Cisco SD-Access Fabric Border Node Role

350-401 By islever Editorial Last updated

Explain the working principles of the Cisco SD-Access solution

Short answer

C The fabric border node serves as the gateway for traffic entering and leaving the SD-Access fabric overlay.

Question

In a Cisco SD-Access wireless network, which device is used as an entry and exit point in and out of the fabric?
  1. fabric edge node
  2. control plane node
  3. fabric border node Correct Answer
  4. fabric access points

Key Takeaways

The question tests knowledge of SD-Access infrastructure roles, specifically distinguishing between the entry/exit point (border) and the internal access points (edge).

This page clarifies the specific role of the fabric border node in a Cisco SD-Access network as the primary gateway for traffic entering and exiting the fabric overlay.

Common mistake: Learners often confuse the fabric edge node (which connects clients to the fabric) with the fabric border node (which connects the fabric to external networks).

Expert Analysis

Why the Answer Is Correct

In a Cisco SD-Access architecture, the fabric border node is explicitly defined as the device that provides routing entry and exit points for all data traffic going into or out of the fabric overlay. It acts as the gateway connecting the VXLAN-based fabric to non-fabric networks, handling the encapsulation and decapsulation of traffic.

Why the Other Options Are Wrong

Fabric edge nodes connect wired endpoints directly into the fabric but do not serve as the gateway to external networks. Control plane nodes are responsible for mapping endpoint IDs to location IDs and do not handle data plane transit. Fabric access points are the wireless radios that connect clients; while they enable wireless access, they are part of the fabric underlay/overlay connection, not the border gateway itself.

Community Comment Notes

Community consensus strongly supports option C. As user cjk3 noted, official Cisco Live slides identify the Border Node as the correct answer. Users like PKamato and landgar referenced the DNA Center deployment guide confirming that border nodes provide fundamental routing entry and exit points. While some users like ImFran argued for D based on the "wireless" keyword, the general definition of an entry/exit point remains the border node's function.

Official Reference

https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf

This link opens the official vendor documentation in a new tab.

Exam Strategy

Focus on the distinct functional roles of SD-Access nodes: Edge (client connectivity), Border (external connectivity), and Control Plane (mapping). Memorize the specific definitions for each to avoid confusion during exam questions.

Frequently Asked Questions

What is the difference between a fabric edge and a fabric border node?

A fabric edge node connects internal clients (wired/wireless) to the fabric, while a fabric border node connects the fabric to external/non-fabric networks.

Does the wireless controller act as an entry/exit point in SD-Access?

No. The WLC manages the APs, but the fabric border node handles the actual routing and traffic exit from the fabric overlay to external networks.

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Discussion 38 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 30 of 38

  1. cjk3 👍 13 Answered C
    See slide 12. Answer C - Border Node https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2020/pdf/BRKCRS-2825.pdf
  2. Clauster 👍 10 Answered C
    SUPER Confusing question but i will decipher it for you: The answer is 100% C and here's why: Here is a question for you: What is one fact about Cisco SD-Access wireless network infrastructure deployments? A. The access point is part of the fabric overlay. < Correct B. The wireless client is part of the fabric overlay. C. The access point is part of the fabric underlay. D. The WLC is part of the fabric underlay So this means Wireless Clients ARE NOT PART OF THE Wireless FABRIC. So if they are not part of the Fabric which Device do they use to enter the Fabric ? = (The AP). Which device do they use to Exit the Fabric ? It cannot be the AP because they use it to enter it. (The only device that a client can use to exit the Fabric is a Border Router) You're welcome :)
  3. ImFran 👍 6
    Seems to be wrong. The question says "SD-access wireless" . The right document is : https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf and the answer D
  4. PKamato 👍 4
    ehm.. the document states "• There are two types of fabric border nodes: border and default border nodes. Both types provide the fundamental routing entry and exit point for all data traffic going into or out of the fabric overlay, as well as for VN and/or group-based policy enforcement (for traffic outside the fabric)" so it's C
  5. landgar 👍 3 Answered C
    • There are two types of fabric border nodes: border and default border nodes. Both types provide the fundamental routing entry and exit point for all data traffic going into or out of the fabric overlay, as well as for VN and/or group-based policy enforcement (for traffic outside the fabric).
Show 25 more comments
  1. AndreasThornus 👍 3
    Good deployment reference guide here for SD-Access Wireless: https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf
  2. Nickplayany 👍 3 Answered C
    Correct answer is C Border node is an entry and exit point for data traffic going into and out of a fabric
  3. MO_2022 👍 3 Answered D
    D. fabric access points
  4. iGlitch 👍 3 Answered D
    WIRELESS
  5. TSKARAN 👍 2
    Given answer is correct; C fabric border nodes There are two types of fabric border nodes: border and default border nodes. Both types provide the fundamental routing entry and exit point for all data traffic going into or out of the fabric overlay, as well as for VN and/or group-based policy enforcement (for traffic outside the fabric).
  6. JackyChon 👍 2 Answered C
    In a Cisco SD-Access wireless network, the device that serves as an entry and exit point in and out of the fabric is called a Border Node (BN). The Border Node is responsible for connecting the SD-Access fabric to external networks, such as the Internet or other non-fabric networks.
  7. Shri_Fcb10 👍 2 Answered C
    Fabric Border Node: This node serves as the gateway to external networks, acting as the entry and exit point for traffic entering and leaving the SD-Access fabric. Fabric Access Points: These are the wireless access points that connect wireless clients to the fabric.
  8. RickAO76 👍 2 Answered C
    Border Node Word for Word for Access Wireless at the end of page 6 to page 7 https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf
  9. Kasia1992 👍 2 Answered C
    I understand how some people may say AP is entry point to the fabric for wireless users but in no way it is the exit point from the fabric for wireless users. Answer should be Border Node. Same as for wired traffic.
  10. Clauster 👍 2 Answered C
    Answer is C. Answer can be found here: https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf On Page 7
  11. KZM 👍 2 Answered C
    FBN serves as the gateway between the SD-Access fabric and external networks. It inspects and filters traffic entering and exiting the fabric, enforcing security policies and controlling routing.
  12. djedeen 👍 2 Answered C
    c: A fabric border node is required to allow traffic to egress and ingress the fabric site https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.pdf
  13. snarkymark 👍 2 Answered C
    https://community.cisco.com/t5/networking-knowledge-base/guide-to-choosing-sd-access-sda-border-roles-in-cisco-dnac-1-3/ta-p/3889472
  14. mansaf 👍 2
    C -> Fabric Border Nodes – A Fabric device (e.g. Core) that connects External L3 network(s) to the SDA Fabric. Identity. Services.
  15. eff3 👍 2 Answered C
    As per usual wording I go with C. Because an EIP has access to the fabric and a Border-Node is the entry
  16. NewLife77 👍 2
    The question specifically uses the word "wireless" thus the answer is access point.
  17. laeppli 👍 2
    "out of the fabric" is key. Another simple question with a sneaky wording
  18. andyforreg 👍 2 Answered C
    Border Node - 100%
  19. helmerpach 👍 2
    my answer: C
  20. bora4motion 👍 2 Answered D
    Going with D
  21. Huntkey 👍 2 Answered D
    Is it not D?
  22. Ciscopass 👍 2 Answered D
    I go with D
  23. zbeugene7 👍 1
    I may be wrong but I think the correct answer is D. Border Nodes have a different purpose, they connect fabric and external networks. In SD-Access Wireless architecture APs are integrated into fabric through fabric edge nodes, therefore it goes from : WL Client wireless connection -> Fabric [ AP wired to -> Edge node-> VXLAN-> WLC ]
  24. Shri_Fcb10 👍 1
    abric access points is not the correct answer is that fabric access points (APs) are responsible for providing wireless connectivity to client devices and forwarding traffic within the fabric. However, they do not manage the entry and exit of traffic in and out of the fabric network itself.
  25. Clauster 👍 1 Answered D
    In an SD-Access Wireless Deployment the Access Points are part of the Fabric, so the second traffic hits the AP you are already in the Fabric, when traffic goes from Network to the Client it traverses the AP as an exit point into the client. In and Out. Answer is D

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