The answer is to enable BGP multipath on the PE routers. This feature allows the router to install multiple equal-cost paths into the routing table, directly addressing the suboptimal path selection caused by duplicate VPNv4 routes from different PEs. In an L3VPN design with a route reflector, iBGP typically selects only a single best path, but BGP multipath overrides this by permitting multiple paths with the same AS_PATH length and next-hop reachability to be used for load balancing. On the Cisco SPCOR 350-501 exam, this question tests your understanding of how to achieve BGP multipath for L3VPN load balancing without altering the route reflector’s behavior—a common trap is confusing this with BGP additional paths, which only advertises extra paths but does not install them locally. Remember the mnemonic: “Multipath installs, additional-path just lists.”
350-501 Networking Practice Question
This 350-501 practice question tests your understanding of networking. 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.
An SP engineer is designing a BGP-based MPLS L3VPN service. The PE routers are fully meshed via iBGP for VPNv4 routes, and an RR is deployed to reduce sessions. The engineer notices that all PE routers are receiving duplicate routes from different PEs, causing suboptimal path selection. Which BGP feature should be enabled to ensure proper load balancing across multiple equal-cost paths?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable BGP multipath on the PE routers
Option A is correct. BGP multipath allows the router to install multiple equal-cost paths into the routing table, load balancing traffic. Option B is wrong because BGP additional paths allows advertising more than one path per prefix but does not directly install them. Option C is wrong because BGP best path selection is a process, not a feature to alter outcomes. Option D is wrong because BGP route reflectors do not influence multipath behavior.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Enable BGP additional paths on the RR
Why it's wrong here
Additional paths allows the RR to advertise multiple paths, but the receiving PE must still configure multipath to load balance.
✗
Deploy a second RR to reduce the number of iBGP sessions
Why it's wrong here
Adding another RR does not affect multipath load balancing; it only provides redundancy.
✗
Configure the BGP best path selection algorithm to ignore interior cost
Why it's wrong here
This only changes which path is selected, not the ability to use multiple paths.
✓
Enable BGP multipath on the PE routers
Why this is correct
BGP multipath allows the installation of multiple best paths for load balancing, given the paths are equal cost and meet similarity conditions.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-501 NAT questions on configuration and troubleshooting.
Networking — This question tests Networking — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Enable BGP multipath on the PE routers — Option A is correct. BGP multipath allows the router to install multiple equal-cost paths into the routing table, load balancing traffic. Option B is wrong because BGP additional paths allows advertising more than one path per prefix but does not directly install them. Option C is wrong because BGP best path selection is a process, not a feature to alter outcomes. Option D is wrong because BGP route reflectors do not influence multipath behavior.
What should I do if I get this 350-501 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-501 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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 →
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.
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.