The document provides an overview of Software-Defined Networking (SDN), highlighting its advantages like virtualization, automation, and programmability that enhance network innovation and management. It discusses the architecture of SDN, emphasizing the separation of control and data planes, and the role of the OpenFlow protocol as a key component. Additionally, it projects that SDN will lead to more flexible and scalable networks, vital for modern cloud environments.

1. Introduction to
Software Defined
Networks (SDN)
By:
Shreeya A. Shah
161060751013
GTU PG SCHOOL
shr.shah.1363@gmail.com

2. Contents:

3. Abstract
Software-defined networking (SDN) has gained a lot of attention in recent
years, because it addresses the lack of programmability in existing
networking architectures and enables easier and faster network innovation
Software Defned Networking (SDN) allows management of all types of
networks under a protocol known as OpenFlow which facilitates nodes and
network monitoring.

4. Limitations of Current Networks
Million of lines
of source code
Billions of gates
Many complex functions baked
into infrastructure
OSPF, BGP, multicast,
differentiated services,
Traffic Engineering, NAT,
firewalls, …
Specialized Packet
Forwarding Hardware
Operating
System
Feature Feature
Cannot dynamically change according to network conditions

5. What = Why We need SDN?
1. Virtualization: Use network resource without worrying about
where it is physically located, how much it is, how it is
organized, etc.
2. Orchestration: Should be able to control and manage
thousands of devices with one command.
3. Programmable: Should be able to change behavior on the fly.
4. Dynamic Scaling: Should be able to change size, quantity
5. Automation: To lower OpEx minimize manual involvement
Troubleshooting
Reduce downtime
Policy enforcement
Provisioning/Re-provisioning/Segmentation of resources
Add new workloads, sites, devices, and resources

6. Why We need SDN? (Cont)
6. Visibility: Monitor resources, connectivity
7. Performance: Optimize network device utilization
Traffic engineering/Bandwidth management
Capacity optimization
Load balancing
High utilization
Fast failure handling
8. Multi-tenancy: Tenants need complete control over their
addresses, topology, and routing, security
9. Service Integration: Load balancers, firewalls, Intrusion
Detection Systems (IDS), provisioned on demand and placed
appropriately on the traffic path

7. Why We need SDN? (Cont)
10. Openness: Full choice of “How” mechanisms
Modular plug-ins
Abstraction:
Abstract = Summary = Essence = General Idea
Hide the details.
Also, abstract is opposite of concrete
Define tasks by APIs and not by how it should be done.
E.g., send from A to B. Not OSPF.
Ref: Open Data Center Alliance Usage Model: Software
Defined Networking Rev 1.0,”
http://www.opendatacenteralliance.org/docs/Software_De
fined_Networking_Master_Usag

8. What is Software Defined Networking (SDN)?
Many Definitions
• Openflow
• Controller
• Openstack
• Overlays
• Network virtualization
• Automation
• APIs
• Application oriented
• Virtual Services
• Open vSwitch
• …

10. new control planes”
“An open solution for
VM mobility in the
“An open solution for customized flow
forwarding control in and between Data
Centers”
“A way to
scale my
firewalls
“A solution to build a very
large scale layer-2 network”“A means to do
traffic engineering
without MPLS”
security/encryption solution”balancers
delivery by optimizing cache
A means to scale my fixed/mobile
gateways and optimize
their placement”
“A wayDtoartead-uCceenthteer”
CAPEX of my network
and leverage commodity
switches”
“A solution to build virtual
topologies with optimum
multicast forwarding
behavior”
“A way to optimize link utilization in my
network enhanced, application driven
routing”
“A means to get
assured
quality of experience
for
my cloud service
offerings”
“A way to distributepolicy/
intent, e.g. for DDoS
prevention, in the network”
cache selection”
“A way to configure my entire
network as a whole rather
than individual devices”
I don’t want to work with my network
vendor or go through lengthy
standardization.”
Simplified
“A platform for deOveplopeinrgatio“Dnevselop solutions at software speeds:
New
“A way to bBuildumsyinoewnssandload
Opportunities”
“A solution to get a global view
of the network – topology and
state”
“A wEantohoatinczebrdoadcastTV
Aplgacielliteyntand
“SDN Is…

11. Real Business Values of SDN
Flexibility:
IT groups can become more agile; deployment backlogs are less problematic
Departments are more easily able to self-select services – including internal, 3rd
party and external cloud services
Automation:
Easily add features (protect, segment, provision, add policies) to new workloads,
groups, branches, employee devices and cloud resources
Visibility drives speed:
Holistic view of application connectivity and external needs (branch, device)
Applications can ask for resources, routes, and access instantaneously
Heat maps (by application) of traffic across the campus and data center
Revenue generation (for SPs):
Service providers can provide more value-added services to customers
Innovation in software can accelerate service delivery and create stickiness

12. Software defined networking (SDN) is an
approach to building computer networks
that separates and abstracts elements of
these systems
What is SDN?(per Wikipedia definition)

13. In other words…
In the SDN paradigm, not
all processing happens
inside the same device

14. Over the years…
this network paradigm
has remained mostly
intact…

15. Where did this SDN “thing” come from?

16. ARCHITECTURE OF SDN
In the SDN architecture, the control and data planes are decoupled,
network intelligence and state centralized, and the underlying network
infrastructure is abstracted from the applications.

17. SDN LAYERS
• Infrastructure layer: it is the foundation layer consists of both physical
and virtual network devices such as switches and routers. All the
network devices will implement OpenFlow protocol to implement
traffic forwarding rules.
• Control layer: This layer consists of a centralized control plane that is
decoupled from the physical infrastructure to provide centralized
global view to entire network. The layer will use OpenFlow protocol
to communicate with below layer i.e. infrastructure layer.
• Application layer: it consists of network services, application and
orchestration tools that are used to interact with control layer. It
provide an open interface to communicate with other layers in the
architecture.

18. Clean Slate led to the development of…

19. OpenFlow is a Layer 2 communications
protocol that gives access to the forwarding
plane of a network switch or router over the
network
What is Openflow?(per Wikipedia definition)

20. 16
Openflow does not equal SDN
Openfl
ow
Software
Defined
Networking
Openflow is one flavor, or a subset, of SDN
© 201 reserved. CiiscCoi

21. OPENFLOW PROTOCOL
• OPENFLOW is an open API that provides a standard interface for
programming the data plane switches. It is a protocol for remotely
controlling the forwarding table of a switch or router and is one
element of SDN.
• It is implemented on Ethernet switches to allow the forwarding plane
i.e. data plane to be managed by a controller present on control plain
in SDN architecture. OpenFlow based controllers will discover and
maintain an inventory of all the links in the network and then will
create and store all possible paths in entire network.
• OpenFlow protocol can instruct switches and routers to direct the
traffic by providing software-based access to flow tables that can be
used to quickly change the network layout and traffic flows as per
users requirements.

22. OpenFlow
Data Path (Hardware)
Control Path OpenFlow
OpenFlow Controller
OpenFlow Protocol (SSL/TCP)

23. OPENFLOW SWITCH AND CONTROLLER
• An OpenFlow Switch contain one or more flow tables that implement
packet lookups and forwarding, and an OpenFlow channel to link to
an external controller .The switch interconnects with the controller
and the controller directs the switch using the OpenFlow protocol.
• The controller can delete, add or update flow entries in flow tables
existing in the switch, both reactively i.e. in response to packets or
proactively, using the OpenFlow protocol.
• Controller make this decision based on policies set by administrator or
depending on the conditions of the network and the decision it makes
is forwarded to flow table entries of all the switches in the network.

24. CURRENT STATUS of SDN
• Google built hardware and software based on the
OpenFlow protocol
• VMware purchased Nicira for $1.26 billion in 2012
• IBM, HP, NEC, Cisco and Juniper also are offering SDNs
that may incorporate OpenFlow, but also have other
elements that are specific to that vendor and their
gear.

25. CONCLUSIONS and FUTURE SCOPE
• In future, networking will rely more on software to pick up the pace
the innovations in networks.
• SDN can transform today’s static networks into more flexible,
programmable platforms to provide scalability to support large data
centers. It will also provide virtualization that is needed to support
automated, dynamic and secure cloud environment.
• Mostly implementations of newly proposed systems, frameworks,
or applications

26. No. Paper Title Year Published Conclusion
1 Next generation networks under
the SDN and OpenFlow protocol
architecture.
2015
2 Sdn and openflow evolution: A
standards perspective.
2015
3 SDN and OpenFlow for dynamic
flex-grid optical access and
aggregation networks.
2014
4 SDN and OpenFlow for converged
access/aggregation networks.
2013
5 Software-defined networking using
OpenFlow: Protocols, applications
and architectural design choices
2014
6 A survey on software-defined
networking
2015

27. REFERENCES
1)
https://qmonnet.github.io/whirl-offload/2016/07/08/introduction-to-sdn/
2)
https://networklessons.com/cisco/ccna-routing-switching-icnd2-200-105/introduction-to-sdn-
software-defined-networking/
3)
https://www.cse.wustl.edu/~jain/cse570-13/ftp/m_16sdn.pdf
4)
https://www.citrix.com/products/netscaler-adc/resources/sdn-101.html
5)
https://www.menog.org/presentations/menog-15/341-MENOG_SDN_April.pdf