The IT Stuff

Cisco has used the three-level hierarchical network design model for years. This older model (also referred to as the switch block model) provided a high-level idea of how a reliable network could be conceived but was largely conceptual, because it did not provide specific guidance.

Cisco therefore developed a newer design model-the enterprise composite model-that is [...]

Advertised Distance is the distance a neighbor router says, or advertises, is the distance to a destination. This is key in electing a feasible successor or backup route. The lower the distance, the better. The lower the value the better the route is believable. These values can be changed with the distance command.

Administrative Distances
Protocol                             [...]

VLANs are broadcast domains in a Layer 2 network. Each broadcast domain is like a distinct virtual bridge within the switch. Each virtual bridge you create in a switch defines a broadcast domain. By default, traffic from one VLAN cannot pass to another VLAN. Each of the users in a VLAN is also in the [...]

General Certifications: Three Levels of Certification

Associate: The first step in Cisco networking begins at the Associate level, which also includes CCENT, an interim step to Associates for those with little job experience. Think of the Associate level as the apprentice or foundation level of networking certification.
Professional. This is the advanced or journeyman level of certification.
Expert. [...]

IGP:

Within a single autonomous system
Single network administration
Unique routing policy
Make best use of network resource
An IGP (Interior Gateway Protocol) is a protocol for exchanging routing information between gateways (hosts with routers) within an autonomous network (for example, a system of corporate local area networks).
IGP’s fall into two categories:

Distance Vector Protocols

Routing Information Protocol (RIP)
Interior Gateway Routing [...]