Qos -Traffic Classification In The Internet

QoS -Traffic Classification in the Internet


Authors

Paula Venosa pvenosa@info.unlp.edu.ar
Nicolás Macia nmacia@info.unlp.edu.ar
Luis Marrone lmarrone@info.unlp.edu.ar


Abstract

In UNLP’s network, like in most of the present networks, a great percentage of the traffic network demand is that of HTTP protocol. At the moment it is around 60%. To be more precise, we would have toclaim that most of the traffic is transported by TCP port 80. Although port 80 TCP is used by default by protocol HTTP, any other application can use it, taking advantage of the fact that usually this port is not filtered and that it is even assigned a greater priority over the others. This work proposes a way to classify traffic at the top level of the application. The objective consists ofapplying effective techniques of QoS, that distinguish HTTP from other protocols as well as different uses which the users generally give, like being navigation, streaming and downloading.



Introduction


At the time of applying QoS in a network, its policies of use determine what type of network they are going to be applied to. It is for that reason that we can come across with two typesof networks:
.- Open or permissive networks.
.- Closed or restrictive networks.
Open networks are characterized by their freedom of access due to the lack of explicit restrictions; whereas closed networks are networks highly controlled with exact guidelines of what is allowed and what is not.
It is quite common in academic environments to find open networks, where anyone can offerInternet services which are accessed in a discreet way or making intensive use of network bandwidth. Therefore, the application of QoS techniques in open networks is oriented towards avoiding the use of the resources by a user leaving other Internet services, or even other users, without resources.










Nevertheless, the proliferation of P2P applications working with ports that areusually not filtered (80 or 53 for example), and also the increasing use on the part of the users of video or radio streaming, degrade the QoS of Internet services and still make its implementation quite more difficult.
The main reason of this problem is that the traffic from the desirable applications is mixed with the traffic of the undesirable ones, so that the application of QoS traditionaltechniques is not suitable in these new scenarios.
The UNLP network, where we develop our research activities, is distinguished for being a network of the open or permissive type. Applying QoS in this network becomes difficult for the reasons above mentioned, mainly due to the great amount of internal laboratories and to the existence of local administrators who respond to differentnecessities. Without QoS mechanisms, symptoms of traffic congestion in Internet services in rush hours would be experienced. Also interruption of services could exist when a user is infected by a virus or worm.
Many techniques of QoS exist that could be applied considering some guidelines as regard an academic network like this one:
.- The tasks of academic character are high-priority ones.
.-Tasks that are not of academic character can go on as long as they do not interfere with the academic tasks.
.-Tasks of academic character would not have to leave other tasks of academic character without service.
While it is very difficult to determine which are academic tasks and which are not, it is not so difficult to know when a task can be interfering with others.
This work gives abrief outline of traditional QoS techniques applied to this type of network, accompanied by their main results (Part 2). These results will show that they would not provide the QoS required by users of this network (Part 3).
In order to offer the required QoS, we set out a solution, based on traffic classification in layer 7 of the TCP/IP stack. The objective consists of applying effective...