CCIE Enterprise study guide
CCIE Enterprise · Work through your exam, one topic at a time.
CCIE Enterprise Infrastructure - often shortened to CCIE EI and grouped under the wider CCIE Enterprise label - is Cisco's expert-level certification track for network engineers who design, deploy, operate, and troubleshoot large enterprise networks. Unlike associate and professional certifications that lean heavily on multiple-choice assessment, the CCIE track is built around a hands-on lab exam in which candidates configure and diagnose live technologies under time pressure, after first clearing a qualifying written exam. The CCIE Enterprise study guide has 5 sections and about 1,680 words.
01Network Infrastructure
For OSPF, know the DR/BDR election precisely: highest interface priority wins, ties break on highest router ID, and there is no preemption - a newly arrived router with a better priority will not take the DR role until the existing DR fails or the interface/process is reset. Priority 0 makes an interface permanently ineligible.
374 words, about 2 min02Software Defined Infrastructure
Cisco SD-Access separates the underlay (IS-IS, OSPF or BGP, often with a routed-access design) from the overlay. The overlay is VXLAN encapsulated data plane plus LISP control plane .
320 words, about 2 min03Transport Technologies and Solutions
A VRF creates a separate routing table; the RD makes otherwise identical prefixes unique inside MP-BGP VPNv4, and the RT controls import/export between VRFs. Packets carry a label stack: an outer transport label (LDP or segment routing) and an inner VPN label.
340 words, about 2 min04Infrastructure Security and Services
TACACS+ runs over TCP 49, encrypts the entire payload, and separates authentication, authorization and accounting - the right fit for device administration. RADIUS runs over UDP 1812/1813, encrypts only the password field, and is the standard for 802.1X and VPN access.
294 words, about 1 min05Infrastructure Automation and Programmability
JSON and YAML dominate configuration payloads; XML remains the native NETCONF encoding. For REST APIs know the verbs (GET read, POST create, PUT replace, PATCH partial update, DELETE remove) and status classes: 2xx success, 4xx client error (401 bad or missing token, 404 unknown resource), 5xx server error.
352 words, about 2 min