In this project I must develop an enterprise network design which is composed from two distinctiv parts : LAN design and WAN design .

In romanian version of this text I described what means LAN and WAN but here I consider it’s no need for that because if you are a visiter on this pages you allready know that.

Today, LANs have metamorphosed into high-bandwidth, high-performance, local area networks that support bandwidth- and CPU-intensive client applications such as live, interactive voice and videoconferencing, as well as e-mail and some of the more traditional forms of data processing.

WANs, too, have experienced radical, evolutionary change. Today, 33.6Kbps is deemed inadequate for most of the needs of even a single user. Just try to give a user a 33.6Kbps modem for use as anything but a paperweight!

Although there are two parts in networking design there is a single set of requirements which every network ( it doesn’t matter what type is ) must follow .

* Functionality-The network must work. That is, it must allow users to meet their job requirements. The network must provide user-to-user and user-to-application connectivity with reasonable speed and reliability.

* Scalability-The network must be able to grow. That is, the initial design should grow without any major changes to the overall design.

* Adaptability-The network must be designed with an eye toward future technologies, and it should include no element that would limit implementation of new technologies as they become available. 

 To design LANs for high-speed technologies and multimedia-based applications, network designers should address the following critical components of the overall LAN design: 

· The function and placement of servers. Servers provide file sharing, printing, communication, and application services, such as word processing. Servers typically do not function as workstations; rather, they run specialized operating systems, such as NetWare, Windows NT, UNIX, and Linux. Today, each server usually is dedicated to one function, such as e-mail or file sharing. Servers can be categorized into two distinct classes: enterprise servers and workgroup servers. An enterprise server supports all the users on the network by offering services, such as e-mail or Domain Name System (DNS). E-mail or DNS is a service that everyone in an organization would need because it is a centralized function. On the other hand, a workgroup server supports a specific set of users, offering services such as word processing and file sharing, which are services only a few groups of people would need.

· Collision detection . You should decide carefully on the selection and placement of networking devices to be used in the LAN in order to decrease the collision detection and media contention on a network. Contention refers to excessive collisions on Ethernet caused by too many devices, each with a great demand for the network segment. The number of broadcasts becomes excessive when there are too many client packets looking for services, too many server packets announcing services, too many routing table updates, and too many other broadcasts dependent on the protocols, such as Address Resolution Protocol (ARP).

· Segmentation Segmentation is the process of splitting a single collision domain into two or more collision domains. Layer 2 (the data link layer) bridges or switches can be used to segment a logical bus topology and create separate collision domains, which results in more bandwidth being available to individual stations.

· Bandwidth versus broadcast domains . A bandwidth domain is everything associated with one port on a bridge or switch. In the case of an Ethernet switch, a bandwidth domain is also known as a collision domain. All workstations within one bandwidth domain compete for the same LAN bandwidth resource. All the traffic from any host in the bandwidth domain is visible to all the other hosts. In the case of an Ethernet collision domain, two stations can transmit at the same time, causing a collision.

Traditionally, relatively low throughput, high delay, and high error rates have characterized WAN communication. WAN connections are also characterized by the cost of renting media (that is, wire) from a service provider to connect two or more campuses together. Because the WAN infrastructure is often rented from a service provider, WAN network designs must optimize the cost of bandwidth and bandwidth efficiency. For example, all technologies and features used in WANs are developed to meet the following design requirements:

· Optimize WAN bandwidth 

· Minimize cost 

· Maximize the effective service to the end users 

Compared to current WANs, the new WAN infrastructures must be more complex, based on new technologies, and able to handle an ever-increasing (and rapidly changing) application mix with required and guaranteed service levels. In addition, with a 300% traffic increase expected in the next five years, enterprises will feel even greater pressure to contain WAN costs.

Network designers are using WAN technologies to support these new requirements. WAN connections generally handle important information and are optimized for price and performance bandwidth. The routers connecting the campuses, for example, generally apply traffic optimization, multiple paths for redundancy, dial backup for disaster recovery, and quality of service (QoS) for critical applications. The table summarizes the various WAN technologies that support such WAN requirements.

When I started to develop this project I intended to follow all of this requirements but it’s long way from therory to practice .

So my enterprise has three location : Cluj-Napoca , Timisoara , Bucharest.Al of this country are in Romania The headquarter is in Cluj-Napoca .

The  image lists a overview on the project. : image