Compare and Contrast Collapsed Core and Three-Tier Architectures

Update: check our new article for new CCNA exam blueprint.

The next topic from the CCNA routing and switching blueprint that I thought would be interesting to go through is LAN-design related:

1.5 Compare and contrast collapsed core and three-tier architectures

While there might be more modern approaches for LAN or Campus designs, for the purpose of this specific exam objective let’s start with three-tier architecture. The 3 tiers are – Access, Distribution, and Core. Tiers are logical, so it doesn’t have to be a dedicated device on each one of them.

Access layer exists in every design because it’s where end devices, such as computers and phones are connected. QoS classification and marking, 802.1X authentication is performed on access tier switches, as these services should be applied as close to the source as possible. Access switches usually have high copper port density and Power Over Ethernet functionality for the phones and access points.

What are the current LAN access platforms? Catalyst 2960-X/XR (can be stackable), Catalyst 3650 (can be stackable), and Catalyst 3850 (stackable), Catalyst 9300 (stackable), and Catalyst 9400 (modular).

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Describe The Effects of Cloud Resources on Enterprise Network Architecture

CCNA Routing and Switching exam has this topic in the blueprint, which I will try to cover in this blog post:

1.4 Describe the effects of cloud resources on enterprise network architecture

•    1.4.a Traffic path to internal and external cloud services

•    1.4.b Virtual services

•    1.4.c Basic virtual network infrastructure

What is a cloud service or resource?

There are many definitions of the term. Many of them refer to public clouds reachable over the Internet. For example, AWS, Microsoft Azure, or Google Cloud Platform. It is often opposed to on-premises private infrastructure. However, cloud service can be private if it has characteristics of public clouds, such as self-service and automation of infrastructure provisioning.

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