3.1 Network Infrastructure concepts

Question 1

Physical isolation

Answer 1

• Devices are physically separate
  –Air gap between Switch A and Switch B
• Must be connected to provide communication
  –Direct connect, or another switch or router
• Web servers in one rack
  –Database servers on another
• Customer A on one switch, customer B on another
  –No opportunity for mixing data

Question 2

Physical segmentation

Answer 2

Separate devices
–Multiple units, separate infrastructure

Question 3

Logical segmentation with VLANs

Answer 3

• Virtual Local Area Networks (VLANs)
  –Separated logically instead of physically
  –Cannot communicate between VLANs without a Layer
  3 device / router

Question 4

SDN (Software Defined Networking)

Answer 4

• Networking devices have different functional
  planes of operation
  –Data, control, and management planes
• Split the functions into separate logical units
  –Extend the functionality and management of
  a single device
  –Perfectly built for the cloud
• Infrastructure layer / Data plane
  –Process the network frames and packets
  –Forwarding, trunking, encrypting, NAT
• Control layer / Control plane
  –Manages the actions of the data plane
  –Routing tables, session tables, NAT tables
  –Dynamic routing protocol updates
• Application layer / Management plane
  –Configure and manage the device
  –SSH, browser, API