BANDWIDTH MANAGEMENT CONCEPTS RESULT

Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005 ISSN 1858-1633 2005 ICTS 38 Our network is fully managed by Informatics Department with a help from Computer Network Laboratory assistant. Recently we run two PC routers with Linux Operating Systems one with Fedora and one with Trustix to connect users in network so they are able to connect to Internet with Network Address Translation NAT technology. By mid end 2005, we plan to use Cisco Router to replace the PC routers which is equipped with network QoS. We also run a web server with mobile-phone Proliant server with dual Xeon Processor, and in mid 2005 we will run a mail server also using mobile- phone Proliant to provide email system in our faculty by our self. The Faculty of Industrial Technology has two buildings, to connect both; we provide a fiber optic backbone. Since March 2005, the Faculty of Industrial Technology implementing WiFi, hence devices equipped with 802.11 devices compliant can connect to Internet. To provide wireless access, we use Linksys WRT54G and WAP54G Access Points.

2.1 The Case

The Faculty of Industrial Technology Network is divided into two main subnets. The first is the north area the new building and the second is the south area the old building. Both servers are running Linux to serve as gateway to connect them to the Internet. Our gateways are installed with Squid to serve as proxy server, which is responsible in caching and distributing Internet connection. To serve the network well, we also run a firewall in our Linux system, so inappropriate access of network can be avoided. Figure 1. Faculty of Industrial Technology Network Infrastructure Design Our networks serve about a hundred computers that connect using cables, and more than fifty wireless devices in everyday of working hours that are connected to Internet. If we count this amount of devices, we will have not less than 150 computers. If we just divide the 256 kbps with 150 computers then each computer will have a connection only in 1.7 kbps, which means that each can download a file in size 100 kilo byte in 470 seconds. Of course, that is not what we expected. So, we need to manage well so that everyone can have its connection fine, although of course we cannot serve in a maximum speed.

3. BANDWIDTH MANAGEMENT CONCEPTS

Bandwidth management is neither a technique nor tool. Successful provision of managed network bandwidth within an organization is likely to involve the application of many tools encompassing a number of different techniques. The techniques and tools an institution uses will depend on a number of factors [2]: • ratio of available bandwidth to existingfuture demand; • need to prioritize some traffic typesusers over others; • resources available to implement bandwidth management strategies; • Organizational experience with products and systems. Before an institution can decide how to solve the problem of reducing bandwidth demands, it is important to be aware of how bandwidth is being consumed at the moment. There are a number of options for doing this. Firstly some of the bandwidth management products have a monitoring as well as proactive mode. Simple Network Management Protocol SNMP based network management solutions give an overall indication of bandwidth ‘hotspots’ on the network that can be further investigated. Here, we use CACTI that connected to our SNMP to manage, monitor, and learn the network behavior in Faculty of Industrial Technology. And also, we learn from log file that produced by our Proxy Server.

4. BANDWIDTH MANAGEMENT IMPLEMENTATION

4.1 Caching

Web caching [3] is the storage of recently accessed pages locally, and delivery of subsequent requests for pages from the local cache rather than the original web site. Caching resources allows a single copy of a resource to be downloaded over an external network connection and then served out to multiple users locally. Caching not only reduces the amount of bandwidth used on the external network connection but can also sometimes provide increased performance for the local users. The prime objective of caching is to improve user response time, but it also reduces the load on the long-distance links. Caching is widely Managing Internet Bandwidth: Experience in Faculty of Industrial Technology, Islamic University of Indonesia – Mukhammad Andri Setiawan ISSN 1858-1633 2005 ICTS 39 used on the Web, and can provide bandwidth savings of up to 40 [1]. After the initial download of the resource the users do not have to compete for bandwidth on what is likely to be a slow and congested external network path. Instead, users will get a copy of the resource delivered rapidly to them from a local cache server over what will normally be a much faster and less heavily loaded internal institutional network connection. A hierarchy of caches may be used to increase the effective cache size and thus improve the hit rate. Push caching attempts to place content in a cache before it is requested, either by looking at other caches, or by predicting usage. Some of these techniques are discussed by Dias 1996 in his research paper in title “A Smart Internet Caching System” as described in [1]. In Faculty of Industrial Technology, Islamic University of Indonesia, we do serve the Internet access by using the Squid proxy server. Squid proxy server is used to cache web pages that have been accessed recently. Squid is implemented as a transparent proxy at the central cache server, therefore, users are automatically served by the proxy for all web access without any browser configuration.

4.2 Access List

Faculty of Industrial Technology is an academic institution. We realize that, most of Internet access should be addressed into academic needs, and should not intended to fulfill needs on leisure such as networking games, peer to peer program such as napster, e donkey, grokster, or bit torrent, and adults sites, and ads. Here, we define access lists that will control user, which site they can visit and which one is not. We also combine access list and firewall in PC router to disable some common port that is used to run some spyware program. Figure 2 show access list that is implemented in our server. acl notsex url_regex -i etcsquidnotsex acl sex url_regex -i etcsquidsex acl utara src 192.168.100.024 acl ftinetwork dst 202.150.76.20029 http_access always_direct allow ftinetwork http_access allow notsex all http_access deny sex all http_access allow utara Figure 2. Access list configuration file As a result, users who try to access site that is prohibited in our access list will get an error message.

4.3 Quality of Service QoS

To provide a good link connection, sometimes a network manager may wish to offer different levels of service for different subsets of the traffic passing over the infrastructure. The QoS technologies allow the manager to do this. The service levels that QoS deals with include dedicated bandwidth, reduced packet loss, controllable amounts of jitter and latency and ensure that particular traffic flows do not swamp the network and drown out other flows. These facilities can help ensure that critical traffic is delivered more reliably [2]. The QoS systems operate only in real-time, in response to the traffic. They do not generally attempt to manage traffic over a longer term. Also, QoS systems normally operate in an environment where the total bandwidth requirement of high-priority traffic is less than the available bandwidth. If high-priority traffic approaches or exceeds the available bandwidth, performance degrades rapidly [1]. To make use of QoS, packets in flow need to be identified, classified and then marked. The identification and classification of packets is performed as described above for traffic shaping, either by source, destination and ports or by using application level probing into the packet contents [2]. In Faculty of Industrial Technology, we manage QoS especially at wireless networking. As we provided free hotspot areas, we must provide a guarantee that the academic staffs still have a good link quality even a numerous wireless user is connecting to our hotspot areas. We provide QoS well so that our bandwidth doesn’t run out quickly because of the use of WiFi devices in our free hotspot areas. The objective of much work on Quality of Service QoS is to provide desired levels of throughput, delay, etc. in the face of unreliable networks and congestion. In wireless networking especially for the free hotspot areas, we provide a low priority to all services, including HTTP, FTP, POP3, SMTP and a few ports that commonly used in Internet. It means that all services will be treated as a lower level priority if there are other activities that is using those services but not using the free hotspot connections. If the priority is set to lower, a lower speed will impact; hence our bandwidth isn’t grabbed out by wireless connections. The free hotspot areas will have its high priority back if the other connection is not using those services.

4.4 Rate Limiting

It is very often that the amount of traffic wanting to use a network link of Internet far exceeds the available capacity of the link. Rate limiting techniques are designed to force some request to reduce their demands for bandwidth based on the protocol, network interface or user involved. Traffic shaping on the other hand aims to spread out the demand for bandwidth and ensure that the most efficient use is made of the available bandwidth. Both of these help to either reduce the required bandwidth to within the Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005 ISSN 1858-1633 2005 ICTS 40 available capacity or to give competing traffic a chance of using the link. We implement this techniques using squid delay pool and reply_body_max_size configuration. Below is our Delay pool configuration in Squid Configuration file which is located in etcsquidsquid.conf as shown in Figure 3. reply_body_max_size 8000000 allow all acl magic_words1 url_regex -i 192.168.100 202.150.76 66.179.235 192.168.1 cisco .pdf netacad uii acl magic_words2 url_regex -i ftp .mp3 .vqf .tar.gz .gz .rpm .exe .rar .avi .mpeg .mpe .mpg .qt .ram .rm .iso .raw .wav .tar.bz2 .bz2 delay_pools 2 delay_class 1 2 delay_parameters 1 -1-1 -1-1 delay_access 1 allow magic_words1 delay_class 2 2 delay_parameters 2 50005000 5000120000 delay_access 2 allow magic_words2 Figure 3. Delay pool configuration File The configuration above shows us, that a user can only download file not more than 8000000 bytes approximately 7800 Kbytes. We prevent user to download a huge file, by doing this, it is expected that bandwidth is not run out quickly. We also create a rate limiting management by using delay pool. Conceptually, delay pools are bandwidth limitations – “pools” of bandwidth that drain out as people browse the Web, and fill up at rate we specify – this can be thought of as leaky bucket that is continually being filled. Delay behavior is selected by ACLs low and high priority traffic, staff vs students or student vs authenticated student or so on [4]. Above parameters create two delay pools. Each delay pool is class 2 which is suitable for aggregate and individual access, so that we can control each client. The first delay pool is initiated to provide a maximum capacity of Internet bandwidth to serve client, it is useful when user try to connect to local area network begin with IP address 192.168.100, connect to site that contain UII means every site that contain UII – Universitas Islam Indonesia – Islamic University of Indonesia, then to download some PDF and DOC file, that usually is needed by academic activities. The second delay pool is initiated to limit the use of bandwidth capacity by limiting each user to download at maximum rate 5000 bytes 40 kbps as an aggregate maximum download of each client, and down the rate of download speed after opening some web pages if the total amount of download exceeds 120000 bytes.

5. RESULT

After implementing bandwidth management, we examine for about a month to see how the effect on clients. As a result, we found that each client can browse sites in a tolerable speed, and sometimes can get a maximum speed. So that, users are never wait to long to get a web page shows up in their browser. We also found that, even at peak hours time, users still can get a download speed at rate 24 Kbps per second, which mean that users can download at rate 3 Kbytes per second. And at peak off time, this speed is increasing up to 240 kbps for each user or about 30 Kbytes per second. We realize that, we need to do more to implement a very optimum bandwidth management. And still, we do some research and collecting data in order to improve bandwidth management quality. ACKNOWLEDGEMENT We thank to Gesit Singgih, Agung Priyamanto and Yudha from Computer Networking Laboratory who has helped in implementing Bandwidth management. REFERENCE [1] Dias, G.V., Managing Internet Bandwidth: The LEARN Experience. 2005 http:www.isoc.orgisocconferencesinet01 CD_proceedingsT86ManagingInternetBand width.htm, accesed May 15 2005. [2] Knight, J.P., Review of Bandwidth Management Technologies, Availability, and Relevance to UK Education. 2003, Loughborough University Computing Services JANET Bandwidth Management Advisory Service. [3] Gettys, J., T. Berners-Lee, and H.F. Nielsen, Replication and Caching Position Statement. 2005 http:www.w3.orgPropagationActivity, accesed May 31 2005. [4] SquidVisolve.com, Squid configuration manual. 2002. Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005 ISSN 1858-1633 2005 ICTS 41 MUE: MULTI USER UML EDITOR Suhadi Lili, Sutarsa, Siti Rochhimah Informatics Department, Faculty of Information Technology, Sepuluh Nopember Institute of Technology Kampus ITS, Jl. Raya ITS, Sukolilo – Surabaya 60111, Tel. + 62 31 5939214, Fax. + 62 31 5913804 email : suhadinwa.iao.co.id, sitiits-sby.edu ABSTRACT Most of software developers nowadays use object- oriented method, and Unified Modeling Language UML is the most popular modeling language used. There are a number of tools for modeling software application in UML notations, but the majority of those tools do not support multi-user mode, where on- line team collaboration is not supported. In this paper, we developed a multi-user UML Editor called WEKMU. This system allows a number of developers to work together at the client site on the same model and the server keep them updated in real time of any change made by others. This feature is implemented using .Net Remoting feature provided in .NET framework. Beside the view synchronization, this system also provide another feature, that is, Undo function, which enables user to return to the previous state of the model Keywords : UML Editor, .NET Framework.

1. INTRODUCTION