Book Image

Building Modern Networks

By : Steven Noble
Book Image

Building Modern Networks

By: Steven Noble

Overview of this book

<p>As IT infrastructures become more software-defined, networking operations tend to be more automated with falling levels of manual configuration at the hardware level. Building Modern Networks will brush up your knowledge on the modern networking concepts and help you apply them to your software-defined infrastructure.</p> <p>In this book you'll gain the knowledge necessary to evaluate, choose, and deploy a next generation network design. We will cover open and closed network operating systems (NOS) along with the protocols used to control them such as OpenFlow, Thrift, Opflex, and REST. You will also learn about traffic engineering and security concepts for NGNs. You will also find out how to fine-tune your network using QoS and QoE.</p> <p>By the end of the book, you'll be well versed in simplifying the way you design, build, operate, and troubleshoot your network.</p>
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
2
Networking Hardware and Software
4
Using REST and Thrift APIs to Manage Switches
9
Where to Start When Building a Next Generation Network

Utilizing QoS


Turning on QoS on traffic from a system is relatively painless. There will be an option in the operating system to enable either CoS or ToS.

Example of QoS in Linux

In Linux, you can see how traffic is being prioritized using the ip link list command, where it will show you what queuing discipline or qdisc you are using:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
 link/ether 74:d4:35:86:74:e6 brd ff:ff:ff:ff:ff:ff

Here we can see that qdisc is set to pfifo_fast; First In, First Out (FIFO). The pfifo_fast queuing discipline will honor some CoS/ToS tags, but this is not guaranteed. In order to utilize QoS, we will need to change the qdisc to something that can be configured, such as Hierarchical Token Bucket (HTB) disc.

HTB utilizes the token bucket algorithm, which does not need to know about outgoing interface characteristics, such as bandwidth. A fundamental part of HTB is borrowing tokens from parent...