Quick Answer
The correct answer is pseudowire, because it provides a point-to-point Layer 2 circuit over an MPLS core, encapsulating Ethernet frames and transporting them transparently as defined in RFC 4448. This technology allows service providers to offer E-Line services by using MPLS labels to forward frames across the core without requiring core routers to participate in the customer’s Layer 2 control plane. On the Cisco SPCOR 350-501 exam, this concept tests your understanding of how pseudowires enable Layer 2 VPN services, often appearing in questions that contrast them with VPLS or EVPN. A common trap is confusing pseudowire with VPLS—remember that pseudowire is strictly point-to-point, while VPLS provides multipoint connectivity. For a quick memory tip, think “pseudo = point-to-point wire,” and recall that RFC 4448 is the key standard for Ethernet over MPLS pseudowires.
This 350-501 practice question tests your understanding of architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A service provider wants to offer Layer 2 VPN services using MPLS. Which technology should be used to transport Ethernet frames across the MPLS core?
Pseudowire
Pseudowire provides point-to-point Layer 2 transport over MPLS.
LDP
Why wrong: LDP distributes labels but does not transport Layer 2 frames.
VPLS
Why wrong: VPLS is for multipoint Layer 2 VPN, not point-to-point.
L3VPN
Why wrong: L3VPN is for Layer 3 services.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Pseudowire
Pseudowire (A) is the correct technology because it provides a point-to-point Layer 2 circuit over an MPLS core, allowing Ethernet frames to be encapsulated and transported transparently. This is defined in RFC 4448 (Ethernet over MPLS) and enables service providers to offer E-Line services. Pseudowire uses MPLS labels to forward frames across the core without requiring the core routers to participate in the customer's Layer 2 control plane.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Pseudowire
Why this is correct
Pseudowire provides point-to-point Layer 2 transport over MPLS.
Related concept
Read the scenario before looking for a memorised answer.
LDP
Why it's wrong here
LDP distributes labels but does not transport Layer 2 frames.
VPLS
Why it's wrong here
VPLS is for multipoint Layer 2 VPN, not point-to-point.
L3VPN
Why it's wrong here
L3VPN is for Layer 3 services.
Common exam traps
Cisco often tests the distinction between point-to-point (Pseudowire) and multipoint (VPLS) Layer 2 services, so the trap here is that candidates may confuse VPLS as the answer because it also transports Ethernet frames, but the question specifies 'Layer 2 VPN services' without mentioning multipoint, making Pseudowire the correct choice.
Detailed technical explanation
Pseudowire encapsulation for Ethernet over MPLS uses a control word (optional) and two MPLS labels: the outer tunnel label (LSP label) and the inner VC label (demultiplexer). The VC label is assigned by the target LDP (T-LDP) session between the two PE routers, ensuring that each pseudowire is uniquely identified. In real-world deployments, pseudowire can also support VLAN tagging (Q-in-Q) and is often used for interconnecting customer data centers or legacy TDM circuits.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Architecture — study guide chapter
Learn the concepts, then practise the questions
Architecture practice questions
Targeted practice on this topic area only
All 350-501 questions
500 questions across all exam domains
Cisco SPCOR / CCNP Service Provider Core 350-501 study guide
Full concept coverage aligned to exam objectives
350-501 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 350-501 questions linked to Architecture.
Practise 350-501 questions linked to Networking.
Practise 350-501 questions linked to MPLS and Segment Routing.
Practise 350-501 questions linked to Automation and Quality of Service.
Practise 350-501 questions linked to Services.
Practise 350-501 questions linked to Automation and Assurance.
Practise 350-501 questions linked to 350-501 fundamentals.
Practise 350-501 questions linked to 350-501 scenario.
Practise 350-501 questions linked to 350-501 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Architecture — This question tests Architecture — Read the scenario before looking for a memorised answer..
The correct answer is: Pseudowire — Pseudowire (A) is the correct technology because it provides a point-to-point Layer 2 circuit over an MPLS core, allowing Ethernet frames to be encapsulated and transported transparently. This is defined in RFC 4448 (Ethernet over MPLS) and enables service providers to offer E-Line services. Pseudowire uses MPLS labels to forward frames across the core without requiring the core routers to participate in the customer's Layer 2 control plane.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
This 350-501 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 350-501 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.