ch 04 --- sdn deployment models

NDI Communications - Engineering & Training

Software Defined Networking (SDN)

Chapter 4 – SDN Deployment Models

Chapter Content

Introduction

Centralized vs Distributed Control

Flow Routing vs. Aggregation

2

Introduction and Terms

Symmetric vs Asymmetric:

In an asymmetric model, SDN global information is centralized as much as possible, and edge driving is

distributed as much as possible.

In a symmetrically distributed SDN model, an effort is applied to increase global information

distribution ability, and SDN aggregation performance ability so that the SDN elements are basically

one type of component.

Floodless vs Flood-based:

In a flood-based model, significant amount of the global information sharing is achieved using well

known broadcast and multicast mechanisms.

In a FloodLess model, all forwarding is based on global exact match typically achieved using

Distributed Hashing and Distributed Caching of SDN lookup tables.

Host-based Vs Network Centric:

In a host-based model, under an assumption regarding use of SDN in data-centers with lots of virtual

machines moving to enable elasticity, the SDN encapsulation processing is already done at the

host HyperVisor on behalf of the local virtual machines.

In a Network Centric design, a clearer demarcation is made between network edge and end points.

Such an SDN edge is associated with the access of Top of Rack device and outside the host endpoints.

Reactive vs. Proactive (pre-populated)

Reactive

First packet of flow

triggers controller to

insert flow entries

Efficient use of flow

table

Every flow incurs small

additional flow setup time

If control connection lost,

switch has limited utility

Proactive

Controller pre-populates

flow table in switch

Zero additional flow setup

time

Loss of control connection

does not disrupt traffic

Essentially requires

aggregated (wildcard)

rules

Chapter Content

Introduction



SDN Domains

OpenFlow Switch

Domain Controller

OpenFlow Switch

OpenFlow Switch

OpenFlow Switch

OpenFlow Switch

OpenFlow Switch

OpenFlow Protocol

Domain Controller

SDNi

Chapter Content

Introduction




Flow-Based

Every flow is individually

set up by controller

Exact-match flow

entries

Flow table contains one

entry per flow

Good for fine grain

control, e.g. campus

networks

Aggregated

One flow entry covers

large groups of flows

Wildcard flow entries

Flow table contains one

entry per category of

flows

Good for large number of

flows, e.g. backbone

9

Summary

Yoram Orzach

[email protected]

Thank You!!!

Coming soon LIVE on our NEW e-Learning portal

ch 04 --- sdn deployment models

Internet