Network Virtualization

Sandip Chakraborty

• In routing table we keep both the next hop IP (gateway) as well as the default interface. Why do we require both?

R1-eth0

R1-eth1

R2-eth0

R2-eth0 R3-eth0

R4-eth0

1. A router may have multiple interfaces !2. An interface may have multiple routers

connected to it !

Finding a next hop essentially means finding a L3 device along withits L2 connectivity – The policies and access control get added upwhen we talk about routing in ISP domains! Essentially, the routers need to do a lots of “CONTROL” operations!

The Life of a Network Administrator is very tough !!!

Can we get a simple view of networking system?

Logical Similarity between Networks and Operating System

Applications

OS Functionalities

Hardware ResourcesMemory, CPU, I/O Devices

System Calls

Applications – Process Communications

Network Services

Hardware ResourcesPhysical Links, NICs, Switches

Service Primitives

Operating Systems Networks

Networks and Operating System – Where they Differ?

Applications

CENTRALIZEDOS Functionalities

Hardware ResourcesMemory, CPU, I/O Devices

System Calls

Applications – Process Communications

Network Services

Hardware ResourcesPhysical Links, NICs, Switches

Service Primitives

Operating Systems Networks

Networks and Operating System – Where they Differ?

Applications

OS Functionalities

Hardware ResourcesMemory, CPU, I/O Devices

System Calls

Applications – Process Communications

Network Services

Hardware ResourcesPhysical Links, NICs, Switches

Service Primitives

Operating Systems Networks

DISTRIBUTEDCONTROLLED

Networks and Operating System – Where they Differ?

Applications

OS Functionalities

Hardware ResourcesMemory, CPU, I/O Devices

System Calls

Applications – Process Communications

Hardware ResourcesPhysical Links, NICs, Switches

Service Primitives

Operating Systems Networks

DISTRIBUTEDCONTROLLED

Network isCompletely Distributed andUnsynchronized

How OS Manages Centralized Control over Distributed Architecture?

Network Virtualization – Decoupling Infrastructure and Service Providers

Infrastructure Providers:

Maintains routers, links, data centres, and other physical infrastructure

Service Providers:

Offer end-to-end services to users

Example from Other Sectors

• Airport authority provides the infrastructure, Airline operators “rent” it and provide end-to-end services.

Solution – Network VirtualizationA

A

A

A

A

AB

B

B B

B B

Packet Forwarding with Network Virtualization

Competing ISPs with different goals must coordinate

Single service provider controls end-to-end path

Today’s Network Network Virtualization

Network Function Virtualization (NFV)

• Network Functions:– Routing / Forwarding– Access Control– Traffic shaping – …

• Implement network functions in software• Load the software functions on-demand to the

hardware

SOFTWARECONTROLLER

Switch A Switch B Switch C

Flow 1VOICE

Flow 2VIDEO

Policy VOPolicy VOPolicy VO Policy VIPolicy VIPolicy VI

Putting These All Together – Software Defined Networking (SDN)

SDN Architecture – Control and Data

Control Logic

Network Administration – Things are Much Simple Now !!

• Fed the control logic (routing logic like routing policies, QoS control, Access control list etc) to the controller

• Controller will convert that logic to switch configuration (through Network virtualization)