NSE7 Advanced Networking and SD-WAN Practice Question
Which routing protocol is commonly used in SD-WAN deployments to exchange routes between FortiGate and the provider edge router in an MPLS network?
⚠ Common exam trap
Watch out — candidates often default to OSPF as a 'common' routing protocol in enterprise networks, failing to recognize that MPLS VPNs specifically require BGP for inter-domain route exchange and SD-WAN overlay integration.
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
✓
BGP
BGP is the correct answer because it is the standard exterior gateway protocol used in MPLS Layer 3 VPNs to exchange customer routes between a FortiGate (CE router) and the provider edge (PE) router. BGP supports advanced features like route filtering, load balancing, and traffic engineering, which are essential for SD-WAN overlay integration with MPLS underlay networks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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RIP
Why it's wrong here
RIP's 15-hop limit and periodic full-table broadcasts cannot carry the scale or convergence speed an MPLS provider edge handover demands. It is tempting because RIP suits small, flat networks needing simple distance-vector routing with minimal configuration. BGP is the protocol actually used for SD-WAN-to-MPLS route exchange.
- ✓
BGP
Why this is correct
BGP is the exterior gateway protocol used between the FortiGate and the provider edge router to exchange routes across the MPLS network, supporting policy and multi-path control. OSPF and RIP are interior protocols, unsuitable for PE-to-CE peering here.
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IS-IS
Why it's wrong here
IS-IS is an interior gateway protocol typically deployed within a single service provider's core, not for customer-edge peering. FortiGate SD-WAN uses BGP to exchange routes with the provider edge router across the MPLS handoff. IS-IS would be the correct choice for routing inside a provider's backbone domain.
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OSPF
Why it's wrong here
OSPF is a link-state IGP for a single administrative domain, so it does not exchange routes with a provider edge across an MPLS carrier boundary. It tempts within an enterprise campus, where OSPF is the standard interior protocol.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This NSE7 practice question is part of Courseiva's free Fortinet 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 NSE7 exam.