- A
The router will establish two separate SD-WAN tunnels, one for each color, and load balance traffic across them.
Each tunnel-interface with a different color creates a separate transport tunnel. SD-WAN can use multiple transports for load balancing and redundancy.
- B
The router will use only the first tunnel interface (GigabitEthernet0/0/1) because the second interface has an invalid color name.
Why wrong: The color '3g' is a valid SD-WAN color (for cellular/3G transport). Both interfaces are valid.
- C
The 'allow-service all' command is invalid on a tunnel-interface; only specific services can be allowed.
Why wrong: The 'allow-service all' command is valid and permits all services through the tunnel.
- D
The configuration will cause a conflict because both interfaces use the same encapsulation (ipsec).
Why wrong: Multiple interfaces can use the same encapsulation (IPsec) without conflict; they are separate tunnels.
Quick Answer
The correct answer is that the router will establish two separate SD-WAN tunnels, one for each color, and load balance traffic across them. This is because in Cisco SD-WAN, each WAN interface configured under the `sdwan` section with a unique `color` creates a distinct transport location (TLOC), and each TLOC builds its own independent IPsec tunnel to the SD-WAN fabric. With two TLOCs—`public-internet` and `3g`—the router becomes multi-homed and can perform load balancing using ECMP or policy-based traffic steering. On the ENCOR 350-401 exam, this scenario tests your understanding of how multiple TLOCs enable transport diversity and load sharing, a common topic in the SD-WAN architecture section. A frequent trap is assuming both interfaces form a single tunnel or that colors are just labels; remember that each color equals a separate tunnel endpoint. Memory tip: "One color, one tunnel—more colors, more load."
350-401 SD-WAN Architecture Practice Question
This 350-401 practice question tests your understanding of sd-wan architecture. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Consider the following SD-WAN device configuration on a Cisco IOS-XE router:
sdwan
interface GigabitEthernet0/0/1
tunnel-interface
encapsulation ipsec
color public-internet allow-service all !
interface GigabitEthernet0/0/2
tunnel-interface
encapsulation ipsec
color 3g allow-service all !
Which statement about this configuration is true?
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
The router will establish two separate SD-WAN tunnels, one for each color, and load balance traffic across them.
In Cisco SD-WAN, each WAN interface configured under the `sdwan` configuration with a unique `color` creates a separate SD-WAN transport tunnel (TLOC). The router will establish two distinct IPsec tunnels—one for `public-internet` and one for `3g`—and can load balance traffic across them using ECMP or policy-based steering. This is the standard behavior for multi-homed SD-WAN edge routers.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The router will establish two separate SD-WAN tunnels, one for each color, and load balance traffic across them.
Why this is correct
Each tunnel-interface with a different color creates a separate transport tunnel. SD-WAN can use multiple transports for load balancing and redundancy.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The router will use only the first tunnel interface (GigabitEthernet0/0/1) because the second interface has an invalid color name.
Why it's wrong here
The color '3g' is a valid SD-WAN color (for cellular/3G transport). Both interfaces are valid.
- ✗
The 'allow-service all' command is invalid on a tunnel-interface; only specific services can be allowed.
Why it's wrong here
The 'allow-service all' command is valid and permits all services through the tunnel.
- ✗
The configuration will cause a conflict because both interfaces use the same encapsulation (ipsec).
Why it's wrong here
Multiple interfaces can use the same encapsulation (IPsec) without conflict; they are separate tunnels.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that `color` values are limited to a small set or that duplicate encapsulation causes a conflict, when in fact `3g` is a valid color and multiple IPsec tunnels are expected for multi-homed SD-WAN designs.
Trap categories for this question
Command / output trap
The 'allow-service all' command is valid and permits all services through the tunnel.
Detailed technical explanation
How to think about this question
Under the hood, each `tunnel-interface` with a unique `color` creates a separate TLOC (Transport Location) in the OMP routing table. The router then establishes a separate DTLS/TLS control connection and IPsec data tunnel per TLOC. In a real-world scenario, an enterprise might use `public-internet` for primary broadband and `3g` for cellular backup; the SD-WAN controller can steer traffic based on SLA policies, and the router can perform active/active load balancing or failover using BFD liveliness detection.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 350-401 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this 350-401 question test?
SD-WAN Architecture — This question tests SD-WAN Architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The router will establish two separate SD-WAN tunnels, one for each color, and load balance traffic across them. — In Cisco SD-WAN, each WAN interface configured under the `sdwan` configuration with a unique `color` creates a separate SD-WAN transport tunnel (TLOC). The router will establish two distinct IPsec tunnels—one for `public-internet` and one for `3g`—and can load balance traffic across them using ECMP or policy-based steering. This is the standard behavior for multi-homed SD-WAN edge routers.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
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 →
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Last reviewed: Jun 24, 2026
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