SDN

Question 1

SDN

Answer 1

Software Defined Networking

Uses software-based controllers to manage and control network hardware dynamically. Virtualisation of networks

Question 2

Traditional Network vs SDN

Answer 2

Traditional Network:
- Management Plane:
- Control Plane: Routing, neighbour tables
- Data Plane: Hardware dealing with packets

SDN separates control plane away from switches and puts it into a Controller Machine

Question 3

Forwarding Devices/Network Elements

Answer 3

hardware that deals with packets e.g. switch, router, access point

Question 4

SDN Controller

Answer 4

centralised manager of forwarding devices, it provides an abstraction of the network which can vary in detail

Question 5

Applications that manipulate networks

Answer 5

Routing, Switching, Monitoring, Load Balancing

Question 6

SDN Workflow

Answer 6

Forwarding Devices receive packets, contact SDN controller for instructions on where to forward the data. They cache the information to avoid overloading the SDN controller with queries

Question 7

Issues with SDN Controller Centralisation

Answer 7

• Reliability
• Scalability

Question 8

Addressing SDN Controller Centralisation Issues

Answer 8

• Clustering: Multiple SDN Controllers
• Regional Segregation: Divide network intro regions so forwarding devices contact nearest SDN Controller
• Hierarchy: Multiple SDN Controllers

Question 9

SDN Benefits

Answer 9

• Networking is flexible, adaptable
• Potentially reduces management costs and increases security