In this site I will try to offer information about
IP Network Quality of Service (QoS) focusing problems
from a practical point of view. The site is divided in 4 sections:
General
QoS information
Windows related
QoS information



 
General QoS information

 

An study of network load

Last year, one customer of mine called me to evaluate some congestion problem they had in their network. The company have had congestion problems in the LAN, very frequent collisions in the main switch and very low performance. Because three protocols were running in the LAN (IPX/SPX, TCP and UDP), I suggested to make an study of the network load to understand better what's going on, just before having any decision.

Flows: how they compete for network resources

I do really recommend to read this document. My goal will be trying to explain how TCP and UDP flows compete for scarce network resources and how these fights, when are well understood for network administrator people, convey in better decision criteria at the moment to make a choice.

Buying additional bandwidth is always the solution?

Don't let of having a read to this document. Perhaps your mind change after reading.

Quality of Service

This document explains briefly what is Quality of Service.

TCP-specific issues to improve the protocol response

There has been discussions about what kind of modification should be made to the TCP congestion control algorithms such that the protocol response could be improved. Here this theme is revisited.

Some TCP related notes

This document summarizes some TCP related concepts that I think are very important to understand Internet behavior.

Some OSPF related notes

I do really recommend to read this document. My goal will be trying to explain how TCP and UDP flows compete for scarce network resources and how these fights, when are well understood for network administrator people, convey in better decision criteria at the moment to make a choice.

Some MPLS related notes

MPLS combines the best network technology of all over the world: Traffic Engineering, QoS routing, Resource assignment, RSVP signaling and IntServ and DiffServ integration.

Some DCCP related notes

DCCP is a new transport protocol being designed by IETF to replace UDP for realtime applications.



 
Linux related QoS information

 

Differentiated Service on Linux HOWTO

Each network card (NIC = Network Interface Card) on a Linux box is drived by a Network Driver which control the hardware. In this document I will explain how to configure these cards.

Querying libiptc HOWTO

This HOWTO written by me and published by The Linux Documentation Project explains how to use the libiptc library included in the iptables package. This document can show you how to use short C or C++ programs to query the internal structure of the firewalling code, to check chains and rules, packet and byte counters, and in a second phase, if you are a little "brave", to modify them.

Voice over IP using Linux

Frequently I've seen in LARTC list questions related to the best configuration to forward Voice over IP (VoIP) packets using Linux. Some people compliant because they can't get the same quality of service they get when using Cisco routers that when using Linux routers. This short document explain why.


 
Cisco related QoS information

 

Network QoS using Cisco HOWTO

This document explains why QoS need to be applied in current corporate LAN and WAN installations and how this technology can be implemented. Some practical examples are given using Cisco routers.

Differentiated Service on Cisco HOWTO

his document explains how to use Cisco to create a Differentiated Service domain. If you have the infrastructure I will be very happy to help you to make this possible; in counterservice you help me to finish the HOWTO. In brief, do it yourself and do not throw your money.


 
Windows related QoS information

 

Network Modeling using Windows

This document presents one of the best Network Modeling tool I ever have seen. It is written to run on Windows, being intuitive, hardly complete, easy to use and really very, very, very powerful. It's a pitty it costs so much. But, don't be worried, smile please, not all is lost. There exists a very good academic version at no cost, for us, poor people who want to learn something new every day. Enjoy, students.