Building a Simple Data Center Network Infrastructure for Campus

ISSN 2356-4393 Building a Simple Data Center Network Infrastructure for Campus Tedi Lesmana Marselino 1), Kiki Bayhaki 2) Informatika, Institut Teknologi dan Bisnis Kalbis Jalan Pulomas Selatan Kav.22 22 Jakarta Timur 13210 1) Email: tedi.lesmana@kalbis.ac.id 2) Email: kiki.bayhaki@kalbis.ac.id Abstract: The Data center is an important part of organization information system. In many situations building The data center is not well planned due to lack of skills of the personnel of IT department, growing network topology, the complexity computer networks, big collection of servers and also the configuration of software and applications. This paper tries to give an approach to build a simple data center, step by step in the area of computer network infrastructure. This approach will use a network simulator program called NetsimK, originally build for teaching tools for a student in learning the fundamental of computer network. NetsimK is a network simulator that is capable of building a complete working network topology. In this case, the simulator is used to build a data center network infrastructure that is designed to support a fully functional data center, which consist of a group of servers where the applications and software resides on it. The result is a template model of networking infrastructure designed for data center in hierarchical style topology. Keywords: data center, networking infrastructure, NetsimK, network simulator, hierarchical topology Abstrak: Data center merupakan bagian penting dalam sebuah sistem informasi organisasi. Umumnya data center tidak dipersiapkan dengan baik karena keterbatasan kemampuan dari personel departemen teknologi informasi, topologi jaringan yang berkembang, kompleksitas jaringan komputer, koleksi server yang besar dan juga konfigurasi aplikasi dan perangkat lunak. Tulisan ini mencoba untuk memberikan suatu pendekatan membangun sebuah data center sederhana, selangkah demi selangkah di area infrastruktur jaringan komputer. Pendekatan akan menggunakan simulator jaringan yang disebut NetsimK, yang biasanya digunakan untuk perangkat pengajaran bagi siswa yang mempelajari dasar-dasar dari jaringan komputer. NetsimK adalah simulator jaringan yang memiliki kemampuan membangun topologi jaringan lengkap yang berfungsi. Dalam kasus ini, simulator digunakan untuk membangun infrastruktur jaringan data center yang dirancang untuk mendukung data center yang berfungsi secara penuh yang terdiri atas kumpulan server-server di mana terdapat perangkat lunak dan aplikasi-aplikasi. Hasilnya adalah sebuah model dasar dari infrastruktur jaringan untuk data center dalam gaya topologi hirarkikal. Kata kunci: data center, infrastruktur jaringan, NetsimK, simulator jaringan, topologi hirarkikal I. INTRODUCTION In a complete information system, mostly the critical infrastructure that must exist is a data center. Data center plays a major role in information system technology and infrastructure. From the perspective of physical infrastructure, data center is a place where all the major equipments of computing system resides such as main computer servers which usually called a server farm, central of computer networking devices and also the main connection to the network provider, the main applications software and software systems that is installed in computer servers. In practice data center is the head of the body of information systems. So critical, data center is then designed to run all the time. It means no down time at all, in 24 hours x 7 days x yearly. To have this sophisticated situation and high reliability of computer systems, data center will be supported by backup. The coverage of backup will include power, servers, network connections, storage devices of the server, applications servers and systems servers. This whole package of full backup systems will guarantee data center will run without any disruption or downtime. Not just servers and all the equipments of the room, one of the main infrastructure that will focuses on this paper is the main infrastructure of the network of data center. A computer network for data center must plan with the 61

Kalbiscientia Volume 1, Nomor 1, Agustus 2014 consideration of the reliability and complexity of the data center. Continuous processing of the application that running on top the computer network infrastructure will also be considered for high availability of the systems. Computer network systems must build with consideration of the whole perspective of the issues of data center as a central of information systems and processing. To do this some methodology and steps will be taken to design and test the plan of computer network infrastructure. The challenge will arise in situations like small or medium organization where the budget only limited for some investments in information technology infrastructure. In this situation usually the information technology team will design the network in minimum standard to support basic function. This can raise a difficult situation in the future when there is a development of the network caused by the needs of the organization like enlarging staff and computation. The design without considering this development will causes big changes in network infrastructure, in turn this can be very costly for rebuilding the network infrastructure. To prevent this condition a well planned design of network infrastructure blueprint must build to anticipate the changing in the future. There is some methodology to do a good design of network infrastructure blueprint like design method using the hierarchical method [1]. Like in the previous explanation data center needs a complex infrastructure support that can be costly, but must anticipate the changing in the future. For a small non-profit organization like education or campus, this can be very challenging. They usually have a very small budget, the building infrastructure is not very complex, but the growth of the information system arises. The situation is like this. When the designer wants to build a network infrastructure, they can not just buy the equipment and deploy the devices and connecting to each other to build a network. This methodology cannot always guarantee the design will be successful when tested. If it fails, then some devices or some equipment will be useless because is not fit the test. Then all the buying will be a waste as expenses. To avoid the cost of failure test, then we can use a network simulator. By using a network simulator much of the potential failure can be avoided through the use of network software simulators. Because the simulator does not use real physical network devices or real physical equipments. But the network simulator can emulate some major network devices or equipments. There is a lot of network simulator which have the capacity to emulate some network devices and other device to build a complete computer network system. One of the software that is easy, cheap or free and complete to emulate most commonly used network devices on the market is NetsimK [2]. NetsimK originally build to aid as a teaching tool for learning a computer network. To do this NetsimK emulates some major computer network devices, such as: router, hub, switch, cloud, UTP cables, serial cables and configuration function to configure network devices and protocols. NetsimK also have computer emulator and application emulator like Windows XP operating system application similar to command prompt, hyperterminal application, and menu to configure IP Address, command prompt application to test the connection using the ping command. The view and interface built to mimic the appearance of the real applications. This tool really helps students to learn how to build and configure computer networks without using a real device but they will have a similar situation when they come to the real one. The other benefits of this tool are beside of the main purpose, the software is really working to design and test a fully functional computer network design. This tool is free and can reduce much failure possibility when test the real computer network. Because the design is already tested in network simulator. The pilot project to design a simple network infrastructure which can anticipate the changing in the future is a campus data center network infrastructure [3]. This type is being chosen because campus is one of the important facilities in society and culture that continues evolving to become more complex organization model that need a serious attention almost like a business model organization. Much campus grows fast and have a large data to be processed using information system, which in turn will need a data center to maintain all the process. A. The Downtime of Computer Systems In this scope computer system will include: servers, network devices, network connections, data storage, camera, environment protection, computer peripherals mainly that located in the data center room or floor or building and other supporting devices. All these components will be seen as the important things that should be cared and protect. The main sources of downtime come from many aspects. Some portion of the country, especially in Indonesia it is because of the lack of power supply from PLN (Perusahaan 62

Listrik Negara) will contribute in the stability uptime of the systems. Outside the Java Island, electricity supply is not very stable. Sometime in a day there will be 2 or 3 hour power outage [3]. This condition can also happen in Jakarta, even though Jakarta is the capital city of the Indonesian Republic. This situation should be anticipated by providing enough UPS power (Uninterruptable Power Supply). But most UPS for medium use, only provide power backup just about 15 minutes. During this period of time the administrator of the server should shut down the servers or systems normally to prevent losses of data or damaging data because of the abnormal shutdown of the systems. Another source of downtime of the systems is human error. Human error problems come from incorrect configuration of the servers or network devices, firewall or other errors. Sometimes human error downtime can make a big problem for availability of the systems. For example: a missed configuration of proxy server can be the cause of unavailability of internet access to the users or an incorrect configuration of firewall can block some portion of access to the user s applications. Security threats are nowadays becoming a major source of problems of the downtime. It happens intentionally. It is not like human error that usually happen without the intention of the person, the threat of computer security happens obvious and clearly with the intention to disrupt, damage, or stolen data from computer systems. This threat can attach to the infrastructure of computer networks, application of the systems or even a physical attack to door lock or compromise room. Computer security threat as the source of downtime systems play as an active activity done by a professional person, groups or organization. It is very rare that this happens unintentionally, because if this happen then can be categorized as human error problems not as a threat. Downtime of computer system is a part of the computer security domain which consist of three aspects, such as: confidentiality, integrity and availability [4]. Availability factors will include the inaccessibility applications from any kind of factors, failures of computer network connections, server fails, computer viruses that damage the applications and disrupting network traffic. Even stolen data using USB stick drive can be categorized into this aspect. In a simple word if the legitimate users cannot access data or information stored in the main storage because of any kind of problems than the availability factors is not compliance with the standard computer security. B. The Causes of Networks Downtime To be more focus to the specific problems to tackle in the design of computer network infrastructure using the network simulator application, this paper will more detail in computer network problems cause downtime. A computer network builds using network devices that are smart enough to control network traffic. A Modern network devices is not like a simple physical, electrical devices controlling electricity as a digital data. A Modern network devices have a complex system which includes an operating system, software application, and tools to control traffic of network data. This can be done using some configuration and management control by the software. The network administrator should configure and monitor these devices using some command or configuration, then the misconfiguration of it, can also result some problem of network connections [5]. Other problems come from misuse of the network devices or access. Without proper understanding of using the internet, can also become the source or network problems. For example: when people do not know how to use the internet wisely, he or she can infect the systems with a virus unintentionally, in turn, it can affect the network traffic drastically that will disturb the stability of the connection. A computer virus of the network like worms can affect a big disruption of bandwidth because this kind of malicious software consumes bandwidth drastically. Although this situation can be mitigated in advance this kind of threat should be recognized and aware. The Process of the installation of computer cabling, power connection and other physical implementation can leave a potential damage in the future. Some vendor who implemented the network installation will leave some problems without proper supervision. They tend to miss a perfect connection of the cables, misplaced some devices, careless power outlet installation and unanticipated rats when lay down cables on top of the ceiling of each room. The other problems of computer network downtime or disruption is devices failures. This problem comes because of the time use of the device which called of maintenance between failures of the device. This must be anticipated using some backup device that identifies with the device being used. And to predict the age of maintenance between failure parameters of each device, the administrator must note the date of manufactured of the device and counter of the used devices, that usually can be found in the configuration of the device. 63

Kalbiscientia Volume 1, Nomor 1, Agustus 2014 C. Continuous Availability of Systems The main concern of data center is to provide continuous availability of the system. As mention earlier in introduction this only one of three aspects of computer security. This availability will provide using fault tolerance capability [6]. Fault tolerance capability is the ability to provide a backup plan for any of systems problems. So the backup plan can be implemented for server, data storage or computer network devices. This backup will replace the used devices or system automatically without the interception of human being or system administrators. With this condition then the high availability of systems can provide for the users. This situation can be illustrated using daily application, we used. Almost every day we use internet application like search engine or free email application. Can we image this services stop for maintenance? Or how may time this public service, although it is provided by a big corporate, doing maintenance schedule and stop the services for a while? Almost none. How can this happen? Do the systems and devices need maintenance? Yes, but all the maintenance process doing without disrupting the services, because the system has fault tolerance capability. This kind of big systems design the backup line, devices, or processes so in any time of maintenance the services will almost never stop. Of course, this can have an exception like major disaster like an earthquake or tsunami, hence there is some approach to mitigate this situation using Disaster Recovery Center (DRC) but this approach will not include in this article. Then the idea of sustainability system that will continuously operate without disruption for giving service to the user will be the fundamental principle of data center and all supporting devices like computer networks. D. Data Center Functions For most common using, the data center will be the central of the computation process. Because all the information will be stored, process, and deliver from and to data center, then it will need a computer network, from the end users to the central of information processing. Usually the all main network devices will reside in the data center room, located close to the servers. This position can have an advantages and disadvantages. The advantages to have all the network devices in the same location as the servers is the maintenance aspects such as HVAC (Humidity Ventilation and Air Conditioning) services will be easier to provide in the same location. The monitoring process and the controlling of the devices in physical ways are more simple when all the cables of many sources come to the central location. The disadvantages of this principal is the possibility of a single point of failure if anything happens at data center, then all the systems equipment will be damaged. The other main components of the data center are computer servers that will consume much of data center space. Servers will placed on a rack or several racks. The server type will be racked server, which measured by U metric. One racked server, usually occupied 3 U in rack server. One rack server of 42 U will consist of 4 or 5 servers, but it depends on the design of each server administrator. Principally this is not an absolute rule, hence a best practice according to each need of the design. Beside of the server, there are also some storage devices such as SAN (Storage Area Network) with the form factor is like the racked server but thicker. These storage devices have a direct connection to the servers through fiber channel cables. Fiber channel is not a network rather than it is an interface. So the fiber channel is not affected computer network infrastructure [3]. Some components that will be used for the most common data center is tape drive devices, monitor switch that will handle multiple server and other supported environment equipment like camera, fire extinquiser, power outlets, UPS, and electrical devices. The important thing is to identify all the components that have connection to computer networks such as: servers, network devices, IP camera, UPS, monitor console switch and door lock. This connection will be very useful for maintenance when the admin of the systems have to access some devices remotely. The vulnerability point in using remote access is when there is no power to support network devices, so all the equipment will be useless. E. Campus Network Campus network is a traditional meaning of a LAN consist of several buildings within a geographic area in the same locations. This scope can be 1 or 2 kilometers. This is a multi storey building, so the important thing to consider is like: floor of the building, connection between building, collection of department of subjects, and other supported unit or building located in the same area. Not to mention 64

the internet connection to the cloud. Although in the same location, some campus can have a building with a distance between each other more than a kilometer at difference address. A typical WAN type of network will suit for this condition. In a campus LAN network the main goal of the data center is identical as data center used in business model. Sometime campus network topology can be more complex that a business organization that only occupied a single office room in a single floor of a building. This kind of topology of the campus network is a very good example and template for other kind of campus building. This type of topology also good because it can be as a representative of a complete network infrastructure used in most common networking technology. Campus network topology can compare to a multi branch office with a headquarter connection to each branch. Many kinds of technology can be applied in this topology like internet connection, WAN, VPN, secure channel. The firewall, bandwidth management tools, remote access control, data storage or even the disaster recovery center is very suited to this kind of topology. On the basis of this consideration, campus network is good to model the network design as a template model [7]. II. METHODOLOGY When building a computer network there a lot of things to consider. This can be messed up for a designer. To give a guidance and systematic way to make a good design Cisco Corp [7] give a model which consist of some principles to be followed. This principle will cover all aspects of network design for a good blueprint of the design. All aspect will cover the necessary things that must have in computer design, to anticipate changing in the future like scalability, adaptability or security. A. Network Design Principles There are many ways to design and build a computer network topology. Some best practices are used in the industry. One of the famous principle, is the following [7]: 1. Functionality 2. Scalability 3. Adaptability 4. Manageability, and 5. Security These five principles in most situations are perfectly suited to consider as a basis for building a complete good network infrastructure. This is a principle for designing a logical topology diagram. Actually, there are two steps to build a network infrastructure, which is: 1. Logical network topology diagram, and 2. Circuit network topology diagram. The five principles, basically, is a principle of logical network topology diagram design. It means that this principle will be considered when designing a computer network topology. The principle number one is a function. This principle, consider about the very basis of computer network function which is connecting two or more devices using a medium such as cables, fiber optic, or wireless. Of course this is important since computer network is about connecting devices. One device can send or receive data through a medium. At the first step, computer network should always perfectly have a function to transport data from one point to the other point. This will be made using the medium, the protocols, the end devices on each side and the data or information itself. Before that, the designer will use a medium for transmission, such as copper wire like UTP / STP cables and or fiber optic. The other medium is electromagnetic signal that will use frequency and modulation. This is a basic concept of computer network communication. So, since the modern computer network not using just a switching electrical devices, but smarter devices that required a simple or even complex configuration, then to build a network there will be some configuration to implement for each device such as a switch, router, firewall and other network smart devices. After configuring the devices, then the test will be engaged. A simple ping program will test the connection between two or more devices. Then it is successful. Even though this test cannot be used as a measurement basis for capability and capacity test, this is enough for function principle. Beware of firewall which can be given a false conclusion. In latest operating system like Microsoft Windows 7, a failing test does not indicate that the connection is failing, but it just blocks a icmp echo or icmp reply protocol. So like it is mentioned earlier to have a complete conclusions about connectivity, we must see some consideration like physical connection and protocol configuration. Since data of the application is differ to protocol for the test, so even though the firewall will block the ping, the data itself still can be transferred through the medium to the other side of the network. The analogy of this situation is like when there is a physical link 65

Kalbiscientia Volume 1, Nomor 1, Agustus 2014 like a bridge, it does not guarantee all the cars, bike and other can pass that bridge if there is a barricade blocked the bridge. Network topology is not a static system or environment. It is growing as far as the growing of the organization and business. Capacity, application, complexity and other factors. The second principle comes as the meaning of capability to grow and changing without disruption of computer network stability. The scalability function has to accommodate a new member of computer network, or to create a new group of VLAN, or to extend the capacity of the switch to accommodate new employees. And this should be done without much or any changing of backbone connection, at least the big picture of network topology. For example, when in the future the organization will require higher bandwidth to support the new way of meeting through teleconference. So the design of network medium should consider the capacity of each medium for later used and upgrade, like UTP cables or fiber optic when at the same time, considering a budget for the investment. This must be put in the middle, which is a minimum design that can be upgraded later without sacrifices the function of the network and capability to adapt changing in the future. The third principle is talking about adaptability. Computer network adaptability means a capability to adopt new technology to replace the old one without neglecting the function of the network. Since computer technology, especially computer network has advanced so robust, fast and vast, the capability of network design to adapt a new technology should be anticipated. This is important to upgrade the network capacity without changing drastically network topology. In a business day, any interruption can cause a big loss of financial benefit, whether it is directly or indirectly. The capability of adapting new technology of computer network technology without changing the network design will prevent much of disruption, or maybe there is no disruption. This kind of network is really good for continuing stability. The end user of the computer network should not be bothered by the maintenance of computer network in the background. This can be done silently, but the impact will get felt directly to the user, when they found the internet speed faster than usual or maybe some workers now can work remotely from their home, or they just join to an access point in the meeting room. This is a capability to absorb a new technology. All the first three of principles has actually been the principles in the making of computer design and development. The next two principles should consider in the process of the computer network activity. The management principle. When building a computer network, the complete finish development of computer network design is not the end of using a computer network, rather it is a beginning. The complexity of using computer network will rise along with the daily activities of computer network. The maintenance process of computer network basically is an activity to keep the network work as maximal as it can. This job is a continuous process because a computer network will operate all the time. Especially the core computer network to support the data center. Maintenance of computer network is a big job to do. It is a part of network management. Start from inventirizing computer network devices, archiving network topology, updating the changing of the network topology, backing up the network configuration, identify network device expiration for upgrading software, and supporting users when having problem using networks, such as connecting their PC to an internet connection [1]. The design of computer network will have a big influence to the maintenance process of computer network. If the design is too complex and not simplified in a fashion model refer to best practice of industry, the maintenance will be so difficult to do. At the end, every time a problem arises, it will need a long time to solve problems. The last principle of designing the network topology is security principle. Nowadays this principle becomes a big issue. Even though a computer network will still function without concern to much of this factor, this will not stand for long periods because the trustworthiness of the users of their network will make them leave it if there is a serious problem in network computing. The Security problem arises from many sources like misconfiguration network devices, misuse of a computer network or a failure of a network device. Most common problems come from human as a factor of threat. Right now hacking activities to get a financial advantage or a political issue triggering cyber terrorism become a vast threat. The Network will always be a target to compromise by this person, group or a professional crime organization. For a data center security issues scope maybe reduce to only organization area, but without neglecting every potential issues that come from internet access or internal access from the employee of the organization. 66

B. Network Hierarchical Model Design Hierarchical network model is not a topology, but just a kind of designing technique or method to put a network design in three types of partitions. The purpose of this method is to segregate the function of each network device and to group the same function. By this technique, complexity of the network topology can be examined partially. So the view will be easier to understand by seeing the topology as a whole picture of a diagram. For large and big topology the design can made cascade using a network cloud. The first part will become the main network devices which centralized most of the traffic, whether it is in or out from the LAN to WAN and vice versa. The core layer will be the backbone of all the network traffic. This layer is a very important layer, because the higher layer the bigger impact that can come to the whole topology when something happen like system failure. Considering this condition, usually the IT department will invest quite expensive devices to handle core layer traffic and control. A device like router, firewall, bandwidth management and network medium like fiber optic are typical network devices that will reside in this layer. Each component will cooperate tightly to form a reliable and fast backbone. Beside of the devices, core layer also the place where main connection to the external network happen. The internet and WAN connection is two examples that almost reside in this layer. This is also the important thing to consider when provisioning, network services to locate Point of Present (PoP) of the network. Core layer will also consist of several main connection to the other part of the building or floor. Main Distribution Facility (MDF) will be the central located in the core layer to give a distribution access to the next switch on distribution layer. Data center as the main point of this paper, obviously, will be located here. Because data center is just a special room with adequate equipment in physical perspective, there is no representation of the data center room in the network topology, but the server farm or collection of server function as a main physical server and as a host of main business software application will be visible in the design. The next layer is distribution layer. On the campus network design topology, this layer will play an important position. A campus network as mentioned earlier will consist with a lot of department following with a person for each department. In most common organization each department will have a segregate network, because they have a different job, classification of document and other restrictions. This situation will push the tight management of network traffic. To provide this segregation or segmentation of the network, then Virtual Local Area Network will take place to give this function. Basically VLAN has been just like a separate physical switch, but with logical technology the LAN can be made in the same devices so it creates logically. This technology in the future of the network will provide flexibility and capability to manage a lot of different subnetwork and variation [7]. Most variation usually come is like when different person in different rooms and building want to keep joining in the same group of network or segment. Using an old technology like physical switch this can be done, but very inefficient and costly. Because each connection must be made physically. With VLAN technology, although the physical connection still needs to be made, but there is only one or two physical connections that exist. The other connection will use a logical connection using a tagging for each network packet, which travel at the same network trunk or link. For the next development of the network, distribution layer will play an important role in providing a backup connection from the access layer to the core layer. Using this backup connection, then the high availability of the network will keep stable for continuous availability. Why distribution layer is so important. If the design puts the backup connection in the core layer, the impact will not cover most of the network traffic, but in the middle of the hierarchy the connection will give a balance between the top and the bottom of network topology. Even though the core layer also very important to have such a backup device for continuous availability of network connection. The last layer is the access layer of topology. In this layer, all end computing devices, usually used by the end user will reside. Most common devices like computer and printer will positioned here. The uniqueness of this layer is, there is a long cable or wide wireless access area between the intermediate connection to the end connection. When using cables like Unshielded Twisted Pair (UTP) or wireless access point, there will be a quite long distance from the end user to the first intermediate network devices in control box or wiring closet. This can give a challenge for an unwanted condition where a mouse can make a serious problem with cables. For wireless connection this can be a vurnarabilites point if the configuration is done correctly. 67

Kalbiscientia Volume 1, Nomor 1, Agustus 2014 III. RESULTS AND ANALYSIS The NetsimK network simulator has some features and functionality that are enough to design an build a complete and functional network infrastructure. The main advantage of course the capability to test the network topology. A. Virtualizing Design There are some devices, NetsimK emulate to function as the real devices. It is categorized as follows: hub/switches, router, host, cables and other as can be seen in Figure 1. The hub or switch is just a simple switch that cannot be managed, so if the configuration need to use a complex switch which can create VLAN then it should use 2950-24+2 device. The router can be more complex router with the almost full function router as the real one. The Userdefine router need to use as the main router. This Userdefine router can add more interfaces like fast ethernet and serial interface. Host consist of three types of end devices, which is: PC, host, and prebuild server DNS and TFTP/ HTTP server. These designs use a host as the end terminal and two servers as a representative server in the area of the data center. Cables emulator support ethernet type, WAN serial and console link. All these types are used in the design. All the WAN connection used serial cables, even though much of a Metronet provider gave an ethernet interface. Other emulator is providing some symbol for network cloud and identification for labeling design. The last tools is Sniffer, but this tool is out of the scope of this paper. NetsimK symbol as mention earlier are some symbols that explicitly be seen by the designer. The NetsimK also has some function that imitates the physical device such configuration tools. This two function is configured for the router and switch. Each device can be configured using Command Line Interface (CLI) and a graphical apps symbol that emulates hyperterminal to create a connection to the console port of router and switch through serial (com) port communication. To test the connection NetsimK simulator emulates DOS prompt that come with Windows XP operating system. To configure an IP address for each PC, the graphical interface is used to set the IP Address and subnet mask. The interface does not look like the real one, but logically it is understandable. B. The Network Topology Figure 2 shows the complete design of simple network infrastructure using NetsimK. The network 68 Figure 1. Network devices emulator in NetsimK topology divided into three parts as a hierarchical network methodology approach. This three parts logically partitioning the works for each sub network. The core part will be the backbone of the whole network. This part consists of network cloud, which is internet cloud and WAN cloud. In this part there is also a main router and main firewall or additional device like bandwidth management. All these components will play a major role and be a central of all traffic. That is why the backbone usually has a very big bandwidth assignment like 10 Gbps. A data center should connect to this core layer without much relay. So in the Figure 2 the core router directly connected to the main switch to the server of HTTP and DNS. Figure 2 Complete simple campus network topology for data center

Figure 3 shows the core layer in more detail. The core router has four interfaces, which is: two serial connections, one is to the Internet Service Provider (ISP), and one more interface going to WAN cloud. And the WAN cloud also connected to another router, that in the implementation this router will represented as a branch location. Two other connections are fast ethernet interfaces. F 0/0 is connected to the main switch of server farm located at his right side of network topology, and F 0/1 connected to the main switch of users. Figure 3. Core layer of campus network Main switch of users will consist of several VLAN to support multi departments organization like campus networks. The switch is an ideal network device to support this situation. The last symbol is PC Console 1. This PC is not part of the network topology. This PC only functions in the NetsimK simulator to play as a console PC to configure both of the router. This PC console, is an emulator of PC Configurator. Figure 4 displays the detail information about typical VLAN that can be used in each department. The important link to the switch is a trunk link. Like Fa 0/1 of the first switch and Fa 0/1 of the second switch. A trunk link is not an access link. Trunk transfer multiple VLAN type into a single network link. In the trunk there are many types of packet data tangging with a special ID (VLAN tagging) that will differ each packet of data so the router, a device at layer 3 of ISO 7 Layer can deliver the packet to the right VLAN at the other port of the switch. This type of configuration which connected different VLAN using a router is called Router on a Stick topology. The last part is an access layer. In this access layer resides all the end devices. The important thing to consider is the access layer will be the critical part about network connection problems caused by a mouse, misconjuction or bad connection. IV. CONCLUSION Simple data center network infrastructure is a generic yet compliance in many cases of campus network design. It is designed to support data center and it is not hard to build and develop also all the configuration is easy to implement. A data center that will be part of the main topology is already anticipated considering the load of the network, the capability of adapting and also management of computer network. The template also flexible to redesign, to adjust the need for each case. IV. REFERENCES [1]. A. Dennis, Networking in The Internet Age. New York: John Wiley & Sons, Inc, 2002, 142, 348 [2]. S. L. Dempsey. http://netsimk.com/. [Online]. http://netsimk.com/ [3]. K. Jayaswal, Administering Data Centers: Servers, Storage, and Voice over IP. Indianapolis, Indiana: Wiley Publishing, Inc. 2006, 453, 283 [4]. I. Sofana, Cisco CCNA & Jaringan Komputer. Bandung: Penerbit Informatika, 2012, 306 [5]. N. Mansfield, Practical TCP/IP Mendesain, Menggunakan, dan Troubleshooting Jaringan TCP/IP di Linux dan Windows. Yogyakarta: Penerbit Andi, 2004, 227. [6]. F. Calzolari, High availability, Geneva, 2006.4 [7]. I. Sofana, Cisco CCNP dan Jaringan Komputer. Bandung: Penerbit Informatika, 2012, 266, 276, 395. Figure 4 Distribution layer of campus network 69