CCIE Cheat Sheet 2026

The 30 highest-yield CCIE facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which Cisco DNA Center feature automates network configuration based on business intent rather than device-level CLI? → Intent-based networking
2. What is the purpose of the LISP protocol in Cisco SD-Access? → Providing mapping between endpoint identifiers and routing locators
3. In MPLS L2VPN VPLS, what is a VSI (Virtual Switching Instance)? → A virtual bridge that emulates a LAN across the MPLS backbone
4. What is the primary function of Cisco Application Centric Infrastructure (ACI) in a data center? → Automate and manage network infrastructure
5. Which transport protocol is typically used by RTP (Real-time Transport Protocol) for voice media streams? → UDP
6. How can you only enable SSH connection on a Cisco Route for management? → Transport input ssh
7. In MPLS L3VPN, which protocol is used to distribute VPN labels and VPNv4 routes between PE routers? → MP-BGP
8. Which Cisco ISE feature allows guest users to self-register and have their access approved by a sponsor? → Sponsored Guest Portal
9. In a Cisco Unified Communications cluster, what is the purpose of the TFTP service? → Providing phone configuration files and firmware to IP phones
10. In Cisco SD-WAN, which plane is responsible for distributing routing and policy information between WAN Edge routers? → Control plane
11. What cryptographic protocol flaw makes TLS 1.0 and 1.1 deprecated for enterprise use? → Vulnerability to POODLE, BEAST, and other attacks due to weak cipher suites and CBC mode
12. What mechanism in MPLS service provider networks controls which VPN routes are imported/exported between VRFs? → Route Target (RT) community
13. In OSPF, what mechanism prevents routing loops by ensuring non-backbone areas communicate only through Area 0? → Backbone requirement
14. What is the primary difference between stateful and stateless firewalls? → Stateful firewalls track connection state; stateless only inspect individual packets
15. Which 802.11 amendment introduced OFDMA and multi-user MIMO for the 6 GHz band? → 802.11ax (Wi-Fi 6/6E)
16. In Cisco ASA, what is the default security level for the 'inside' interface? → 100
17. In the Cisco hierarchical network design model, which layer is responsible for routing between VLANs and applying QoS policies before traffic enters the core? → Distribution layer
18. What channel width provides the highest throughput in 802.11ac but requires the most contiguous spectrum? → 160 MHz
19. Which Cisco WLC feature automatically adjusts AP transmit power and channel assignment to optimize RF coverage? → RRM (Radio Resource Management)
20. What is the adminitrative distance of EBGP route? → 20
21. What is the main purpose of the Cisco Data Center Network Manager (DCNM)? → To monitor and manage data center network infrastructure
22. In Cisco ISE profiling, which probe collects device information based on DHCP option 55 (parameter request list)? → DHCP probe
23. What QoS mechanism is used by service providers to guarantee bandwidth and bound latency for real-time traffic like voice? → DiffServ with Per-Hop Behaviors (EF for voice)
24. Which authentication framework is used in WPA3-Enterprise for improved security over WPA2-Enterprise? → 192-bit security suite with GCMP-256
25. What is the role of the Cisco Nexus 9000 series switches in a data center environment? → They are designed for high-performance, low-latency data center networks.
26. Which QoS mechanism uses a token bucket algorithm to limit traffic bursts while allowing sustained rates? → Traffic shaping
27. Which IKE version is recommended for modern IPsec VPN deployments due to improved security and mobility support? → IKEv2
28. In Cisco wireless, what is the function of the CAPWAP protocol? → Providing tunnel between lightweight APs and WLC
29. Which Cisco Firepower feature provides advanced malware protection by continuously analyzing file behavior after initial inspection? → AMP (Advanced Malware Protection) retrospective analysis
30. In MPLS, what is the label imposed at the ingress PE router called? → Transport label