mediumMultiple ChoiceObjective-mapped
LISP for Wireless Mobility in SD-Access
An architect is designing an SD-Access fabric for a campus with multiple buildings. The design must support wireless clients seamlessly roaming across fabric edge nodes. Which technology is used in the fabric to provide mobility for wireless endpoints?
Quick Answer
The answer is LISP, or the Locator/ID Separation Protocol, because it decouples a wireless endpoint’s identity (EID) from its location (RLOC), allowing seamless roaming across fabric edge nodes in an SD-Access campus. In the fabric, LISP maintains a centralized mapping database that tracks where each wireless client is attached, so traffic is forwarded to the correct edge node without requiring re-anchoring or tunnel reconfiguration as the client moves between access points. On the ENCOR 350-401 exam, this question tests your understanding of how SD-Access handles wireless mobility without traditional controllers—a common trap is confusing LISP with VXLAN or OTV, but remember that VXLAN handles data-plane encapsulation while LISP manages the control-plane mapping for endpoint mobility. A helpful memory tip: think of LISP as the “phonebook” for wireless clients—it looks up where they are (RLOC) by their name (EID), so they can roam freely without losing their connection.
⚠ Common exam trap
Cisco often tests the misconception that VXLAN alone handles mobility, but the trap here is that VXLAN is only the data-plane encapsulation; LISP is the control-plane protocol that actually enables endpoint tracking and seamless roaming in SD-Access.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
LISP
LISP (Locator/ID Separation Protocol) is the correct technology because it decouples the endpoint identifier (EID) from its routing locator (RLOC), enabling seamless roaming across fabric edge nodes. In SD-Access, LISP maintains a mapping database that tracks wireless endpoint locations, allowing traffic to be forwarded to the correct fabric edge without re-anchoring or tunneling changes as clients move between access points.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
LISP
Why this is correct
LISP handles endpoint mobility by updating the EID-to-RLOC mapping when a client roams.
- ✗
VXLAN
Why it's wrong here
VXLAN is the data plane encapsulation but does not handle mobility control.
- ✗
OTV
Why it's wrong here
OTV is used for Layer 2 extension between data centers, not for fabric mobility.
- ✗
MPLS
Why it's wrong here
MPLS is not used for endpoint mobility in SD-Access.
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Same concept, more angles
2 more ways this is tested on 350-401
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which two statements about LISP in Cisco SD-Access are true? (Choose two.)
medium- ✓ A.The LISP Map Server stores the mapping between endpoint identifiers (EIDs) and routing locators (RLOCs).
- B.LISP encapsulation is used to forward data traffic between fabric edge nodes.
- ✓ C.The LISP Map Resolver processes Map-Request messages and responds with the RLOC of the destination EID.
- D.LISP uses TCP port 4342 for control plane communication.
- E.The EID in LISP represents the MAC address of the endpoint device.
Why A: LISP (Locator/ID Separation Protocol) is the control plane in SD-Access. The Map Server (MS) maintains the EID-to-RLOC mapping database, and the Map Resolver (MR) handles Map-Request queries. The EID represents the endpoint identity (IP address), while the RLOC is the routing locator (IP address of the fabric node). LISP does not perform encapsulation; VXLAN does. LISP uses UDP ports 4342 (data plane) and 4341 (control plane), not TCP. The EID is typically the host IP, not the MAC address.
Variation 2. An architect is planning a Cisco SD-Access fabric deployment. The design must support host mobility across multiple fabric edge nodes while ensuring consistent policy enforcement. Which fabric component is responsible for tracking endpoint locations and mapping them to the fabric?
medium- ✓ A.Fabric control plane node
- B.Fabric border node
- C.Fabric edge node
- D.Fabric wireless controller
Why A: In Cisco SD-Access, the fabric control plane node (based on LISP) is responsible for maintaining the endpoint database (EID-to-RLOC mappings). When a host moves between fabric edge nodes, the control plane node updates the mapping, ensuring consistent policy enforcement by providing the correct location information to all edge nodes.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.