350-501 Networking Practice Question
Which technology should be used to provide per-flow load balancing across multiple equal-cost paths in an MPLS network while preserving packet order?
⚠ Common exam trap
Cisco often tests the distinction between per-flow and per-packet load balancing, and the trap here is that candidates confuse ECMP with per-packet round-robin, assuming both preserve order, but only per-flow hashing guarantees packet ordering within a flow.
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
✓
ECMP with a hash algorithm based on layer 3 and layer 4 headers
ECMP with a hash algorithm based on Layer 3 and Layer 4 headers is the correct choice because it provides per-flow load balancing by computing a hash over source/destination IP addresses and TCP/UDP port numbers, ensuring that all packets belonging to the same flow are forwarded over the same equal-cost path. This preserves packet order while distributing different flows across multiple paths in an MPLS network.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ECMP with a hash algorithm based on layer 3 and layer 4 headers
Why this is correct
ECMP hashing preserves flow ordering.
- ✗
LAG with default hashing
Why it's wrong here
LAG is for link aggregation, not per-flow across ECMP.
- ✗
Policy-based routing with next-hop per destination
Why it's wrong here
PBR does not provide per-flow load balancing.
- ✗
Per-packet round-robin load balancing
Why it's wrong here
Per-packet may reorder packets.
Go deeper
Related to this question
About these practice questions
This 350-501 question is part of Courseiva's 971-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.