CCNP-Level Interview Questions and Answers
These are the questions asked once you're past entry level — for senior network engineer and infrastructure roles. They probe depth: multi-area OSPF, BGP policy, redistribution risk, and enterprise WAN design. Build the depth in our CCNP course and redistribution guide.
How to prepare
CCNP interviews want to see you reason about trade-offs and failure modes — not just define terms. Be ready to explain why redistribution can loop, when you'd choose OSPF over EIGRP, and how SD-WAN changes traditional WAN design. Concrete war-stories (even from labs) go a long way.
Frequently asked questions
What is route redistribution and why is it risky?
Injecting routes from one protocol into another. It's risky because protocols measure 'best' differently and mutual redistribution at two points can create routing loops — mitigated with route tagging and filtering.
What is a VRF and when would you use one?
A Virtual Routing and Forwarding instance — separate routing tables on one device, used for multi-tenant separation or keeping certain traffic (e.g. management) isolated from the main routing table.
How does OSPF scale in a large enterprise?
Through a hierarchical area design — multiple areas attached to a backbone (area 0) via ABRs, limiting how far detailed LSAs flood and keeping SPF calculations manageable.
What is the purpose of a route reflector in BGP?
It removes the need for a full iBGP mesh by re-advertising iBGP routes to its clients, dramatically improving scalability in large autonomous systems.
What is DMVPN and what problem does it solve?
Dynamic Multipoint VPN — it lets branch sites build on-demand direct tunnels to each other (not just to a hub), using NHRP to resolve dynamic addresses, reducing hub bottlenecks.
What is the difference between GRE and IPsec, and why use them together?
GRE tunnels any traffic (including multicast/routing protocols) but doesn't encrypt; IPsec encrypts but has limited multicast support. Combined, GRE carries the routing traffic and IPsec secures it.
What does SD-WAN change about traditional WAN design?
It centralises policy and path selection across any transport (MPLS, broadband, LTE) via a controller, enabling application-aware routing and easier multi-site management than traditional per-router configuration.
How would you troubleshoot an OSPF neighbor stuck in EXSTART?
Check for an MTU mismatch between the two interfaces first — it's the most common cause — then verify duplex/speed and any ACLs blocking OSPF multicast.
Related articles
Want hands-on training?
Learn this on real Cisco lab devices with placement support at Attila Technologies, Ahmedabad.