
AWS Certified Advanced Networking – Specialty (ANS-C01) Certification Guide
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AWS uses the layer 2 VLAN concept to extend the Direct Connect virtual interface (VIF), for connectivity to AWS resources across the DX. While the physical cabling of Direct Connect can be provisioned using as little as a single cable, or it can be as complicated as extending across an entire WAN, the VIF architecture is the same irrespective of the physical connectivity. But before we start talking about VIFs, let’s spend a little time understanding the concept of a VLAN and how it ties back to VIFs.
At OSI layer 2, an Ethernet frame includes encapsulation for the payload, or the application data, and a few other fields. Without getting into the deep details of the OSI model and Ethernet technology, the most important fields include the source and destination MAC address (the addressing mechanism at layer 2) and a VLAN tag. VLAN stands for virtual local area network and is a logical way to separate networks utilizing the same physical infrastructure...