Client Local Server Applications And Services

Published Date: 02 Nov 2017

In the early age of network technology, there was a strong believed that wired networks are much faster and secure than wireless networks. But with the enhancement of network technologies and improvement in wireless network standards have eroded those speed and security differences.

Wireless network devices are connected through radio waves to the Internet and to your business network and its applications. When a laptop is connected to a WiFi hotspot, it is actually connected to that business's wireless network. Wireless network is a modern substitute of a wired network that relies on copper and/or fiber optic cabling between network devices.

Convenience and cost advantages of wireless LANs over wired networks are discussed are discussed below.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Mobility: Wireless LAN systems can provide LAN users with access to real-time material anywhere in their organization. Wireless network provides productivity and service opportunities, which may not be possible with wired networks.Thousands of universities, hotels and public places having public wireless connections, make it easy to connect to the world of network at very cheap rates.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Simplicity of installation: wireless LAN system can be fast and easy and can remove the hurdles of managing the cable and altering them on the walls and ceilings.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Cost effectiveness: initial expenses for wireless LAN hardware are higher than the cost of wired LAN hardware but the overall expenses and life-cycle cost can be significantly lower. Long-term cost benefits are greatest in dynamic environments.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Scalability: in order to meet the needs of specific applications and installations, wireless LAN systems can be configured in a variety of topologies. To enable users roaming over a broader area or to provide services to a few users, wireless LANs can be easily configured ranging from peer to peer networks.

In this essay we explore the details of designing and implementing a wireless and mobile network for a university having over five campuses, each about 5km apart.

Since early 1970s, mobile wireless industry has evolved tremendously with respect to the creation and revolution of its technology. A few competitive and popular technologies are briefly described here:

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Wi-Fi indicates usage of specifications of the 802.11 family. It is a popular wireless technology that allows an electronic device to wirelessly connect to a high speed internet connection to exchange data. It allows connecting to a wireless access point which has a range of about 20meters (indoor).

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ WiMAX is another popular competitor which provides wireless alternative to cabling with a portable mobile connectivity across variety of devices. Being originally based on the 802.16e-2005, mobile WiMAX has been deployed across the world in many countries.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Bluetooth, a short range wireless connection specification, describes interconnecting PDAs, mobile devices, or laptops. Originally standardized as 802.15.1, Bluetooth is used in a quite many applications today.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ UWB or Ultra WideBand, is used to transmit large amounts of digital data. A frequency band spread wide over the spectrum is used for short distance communication as long as 200 feet. Signals are carried across obstacles and doors at higher power and limited bandwidth.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Wireless Application Protocol or WAP is a way to standardize how wireless devices can be configured for use of internet access. WEP (Wired Equivalent privacy) is another security protocol is designed to provide security comparable to that of a wired network. It is included in the 802.11 Wi-Fi standard.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ 802.11 is a complete standard to implement Wireless LANs. Wi-Fi brand is used to provide the basis for the wireless network products using 802.11 specifications. It is an evolving family of standards worked upon by the IEEE (Institute of Electrical and Electronics Engineers). The family consists of a series of modulation techniques that are based on a single protocol.

With respect to technologies, the requirements of a campus network can be categorized as internal and external. According to (http://community.brocade.com/docs/DOC-2886) users, applications and devices (as personal PDAs, laptops, computers) are included to external requirements. Whereas, internal requirements include quite a few technologies which include, layer 2 and layer3 technologies, the Wireless Local Area Network (WLAN), and other network management and IP network services.

The IEEE's 802.11g is a high bandwidth standard descendant to the previous accepted standard 802.11b or previous Wi-Fi standard. 802.11g has a maximum speed of 54Mbps while 802.11b has an 11Mbps (Megabits/sec) of maximum speed. An 802.11g has an access point which is compatible with both 802.11b and 802.11g clients, therefore, a laptop which has 802.11g card can easily access the previous 802.11b and also a new 802.11g access points. The main advantages of 802.11g over 802.11b are as follows:

Higher bandwidth of 54 Mbps,

Cheaper than 802.11a, and cost similar to 802.11b. Like 802.11b.802.11g uses 2.4GHz frequency band.

Backward compatible with 802.11b standard.

The main disadvantages are:

At least 50% higher cost than 802.11b.

Not widely supported by the machines like laptops and PDAs.

While making any procurement in the future, think about the availability of dual band devices. The devices which are compatible with both 802.11a and 802.11g are a better idea to purchase for the future expansion and compatibility in diverse network environments.

 802.11g is a descendant of 802.11b having all the properties of 802.11b which includes the backward compatibility with 802.11b and the higher performance related with OFDM transmission. Cisco based 802.11g products are the other reasons to consider the advantages which are outside of the advantages of 802.11g itself.

These products provide an integrated RC4 encryption engine which provides Wired Equivalent Privacy (WEP) and WPA security having no performance degradation and also provides an encryption engine that is useful for both the RC4 and the Rijndael algorithm for WEP, WPA, and also Advanced Encryption Standard (AES) encryption for high-speed support for the forthcoming 802.11i standard and FIPS-140 compliance.

The Cisco 802.11g is a fifth generation of 2.4 GHz which corresponds to building ahead previously 802.11 and 802.11b radios. These radios provide better performance as compared to the previous 802.11b-only radio while operating in 802.11b DSSS mode. For applications where 802.11g is not a requirement, one should still consider the 802.11g radio can be consider for applications purposes where 802.11 is not required. Due to its dependency on previous 2.4-GHZ technology it has the advantages of cost reduction in engineering and economies that faced the increasing volumes of 802.11b.

Though the building cost of 802.11b and 802.11g is similar and Cisco provides its 802.11g products similar to its 802.11b in price and customers can get the products with increased performance, with improved rang and with robust security in the same price.

The main reason of not to buy the 802.11g devices over 802.11b is the it does not provide alone the type of capacity which was provided by the 802.11a previously and this problem has the answer called dual-band.

Network professionals are beginning to deploy such dual-band infrastructure so that they can have the better capacity that is available with 802.11a due to the reason that WLAN capacity needs to increase.802.11g is not a substitute of 802.11a but a part of WLAN architecture, and it is used as a bridge between 802.11b(Low capacity) and dual-band(High-capacity) networks..

A campus network is a building or group of buildings all connected into one enterprise network that consists of many local-area networks (LANs). Implementation of Wi-Fi networks have been improved a lot in the field of its speed and ease of access, the methodology of radio frequency (RF) is generally unchanged. With the increase of network users and its access the WLAN in a limited physical space remains a challenge. To overcome these challenges, ( ) architecture optimizes and implements a successful WLAN design. It includes the following general steps:

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Plan: plans the basic requirements of a device and determine applications such as service level agreement (SLA), bandwidth, frequencies, protocols, etc.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Design: it determines density, antennas, cell sizing, site survey, coverage, etc.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Implement: Install, tune, test, establish baseline, etc.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Optimize: Monitor, adjust, report, review baseline for SLA.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Operate: Cisco Wireless Control System (WCS) monitoring, capacity monitoring, troubleshooting tools and reporting tools, etc.

The general concepts basic high-density Wi-Fi designs remain true for many locations. But it is important to know that the solution presented over here does not fit to every WLAN design scenario. Rather, the idea behind the explanation of the challenges in WLAN design is to offer successful strategies so that engineers and managers realize them and are able to articulate the impact of design decisions will have.

The design of a campus network is greatly influenced by the networking services that are to be offered in that campus. The traffic patterns inside a campus network are identified by the critical applications and the network capacities required by these applications. Quite few network parameters are influenced by the kind of the network traffic. Transmission medium, bandwidth, response time and many other performance parameters are thus involved.

According to [] following are few requirements and demands of the kind of services and applications common to campus networks:

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Peer-to-peer Applications and Services:

The applications in which most of the network traffic passes through the organization’s network, from one edge device of the network to another are regarded as peer-to-peer applications. Such applications include,

Video Conferencing, Voice over IP, sharing of files and instant messaging. Through instant messaging, the communication takes place directly between the two peers as soon the connection is established. Video conferencing as such as IP telephony requires more network resources as well as bandwidth and Quality of Service. Through voice over IP or IP phone calls, a central telephony manager helps two peers to establish communication. As soon the connection is established, the communication takes place directly between the two peers. QoS (Quality of Service) are restricted here as well in order to handle delay and jitter which affects the telephone quality. File sharing allows operating systems or some applications to access data directly from other workstations.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Client-Local Server Applications and Services:

Following the client-server application’s 80/20 workgroup rule, earlier, clients and servers were attached to a same LAN segment through a network device. According to the rule, only around 20% of the traffic leaves the LAN segment whereas 80% of it is local to the LAN. As the traffic increases over the corporate network, a network can be split into segments with users on fixed locations. Each segment has a local server to deal with the applications. This is when same VLAN exists for the servers and the users whereas the administration or the department administrators are responsible for controlling and managing these servers. The campus backbone is used to exchange data over a different VLAN, however, most of the traffic generated is intended for the same segment. The traffic that generates to pass to another segment can be easily handled and the operation is not critical. Lower performance requirements are incurred by such traffic which goes to the internet through one common segment, which is lower than the requirements of the traffic to local segment servers.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Client-to-Server Farm Applications:

Larger organizations ensure that the access to critical applications by the users is properly controlled, rapid and consistent. As insignificant delay is incurred by the high-performance multilayer switches, and as network bandwidth cost is reduced, therefore, it is technically feasible to locate the servers centrally as compared to groups, and it also reduces support cost.

The servers are located in a common Server farm to keep the management costs lower and to fulfill the demands as well. A highly secure and reliable network infrastructure providing redundancy and resilience is required in order to use server farm which in turn is capable of providing satisfactory throughput. In such environments, fastest LAN technologies coupled with high end switches are used, for example Gigabit Ethernet.

In order to reach a server farm, application traffic may have to pass quite a few wiring closets, LANs or VLANs, in a large organization. A 20/80 rule applies here with 20% local LAN segment traffic and 80% traffic which crosses the segment to enter internet or the centralized servers. For example; file servers, organizational mail servers, and database servers.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Client-to-Enterprise Edge Applications:

Servers on the Enterprise edge are used by such client-to-enterprise edge applications in order to exchange data within the organizations and outside to the public servers. The critical issues encountered here are related to security and high availability. Moreover, consistent exchange of data should take place with the external entities. Such applications residing on the enterprise edge may prove to be critical to the process flow of the organization and hence can increase cost by outages.

DNS servers and external emails as well as the public web servers are the examples of typical enterprise edge applications which can be found in any organization and are web technologies based E-commerce applications also tend to place their e-commerce servers at the enterprise edge. Two way data replication makes it important to communicate with these servers.

Therefore, high availability and redundancy, as well as security and resilience are known to be most important requirement in case of these applications.

With the growth in the cellular industry over the last decade had spurred the mobile manufacturing industries to manufacture the smart phones which provide ease of use to the customers worldwide. Smart phones are equipped with most of the latest wireless technologies like Wi-Fi and Bluetooth. It is hard to believe that someone has a phone which does not have a Bluetooth in it. 90% of the mobile phones in the market are now equipped with Bluetooth which will reach to 100% over the next few years. Then there is a question arise that what can we do with this Bluetooth technology to gain a positive use for the students in the universities apart from just sharing apps and files.

"In which rooms are my lessons?", "Do they start this week or next week?", "Where is the examination office or the office of the registrar?", "what is the procedure to register the course?" These are typical questions both the freshmen and senior students are asking at the beginning of each new semester. There should be a campus information system which supports the student life cycle in a personalized way at any time, at any locations. We have a Bluetooth technology that can be use to start a campus news and information system for the students to get updated with their day to day activities, class schedules and addresses for different offices while on the go using just the phone in their hand. Motivated by the development of powerful mobile devices and the semantic web, there should be Semantic Mobile Environment. In such an environment, so-called service nodes are installed at chosen points of interest. These service nodes broadcast messages to nearby mobile users using Bluetooth wireless technology. The kind of message depends on the location of the broadcasting access point. For example a bookshop could send its latest offers, or the University restaurant could present its menu or a faculty presents the schedule of events to the students. The applications of the concept are vast and have many areas, e.g. an access point near the cafeteria can broadcast its menu and special offers, library can broadcast the new books arrivals, admission department can broadcast the details and procedures for registration and so on.

The proposed concept can provide more sophisticated network for students to stay informed and up to date with the day to day activities and also the university can take advantage of the network to issue their news, rules of conduct, and announcements.

In a nutshell every student in the university always has a cell phone and 90% of these cell phones have the integrated Bluetooth technology. So this technology can be put to use by creating a Bluetooth based campus news and information system to keep the students up to date.

In order to link buildings as in given scenario, with campuses 5 km apart, an appropriate idea will be to use extended LANs. A wireless LAN bridge has the capability to interconnect networks that are 5 km apart. An easy way of connecting buildings, without the usage of cables is through wireless bridge. Its functionality is similar to that of footbridge. As a footbridge links two points, similarly, wireless bridge links two buildings. Wireless LANs at each of the campus can thus be connected. Another spread spectrum radio technology known as AIRLAN, enables the creation of a wireless backbone, which has the capability of extending to as far the distances which are beyond a LANs’ each.

Although it may sound expensive or costly, however, it overcomes the need of and the expenses over leased lines.

An alternative may be to use long range wireless bridges in order to entertain the areas where wireless bridge may not be able to provide services. Similar technology as spread spectrum radio technology is used in such long range wireless bridges to provide Ethernet and Token Ring bridging. The distance it covers is however extended to up to 40 km.

As by using wireless LAN bridges, use of long range wireless bridges also gets rid of the expenses over microwave connectivity or the T1 lines.

Areas with difficult physical installations as campuses and hospitals require a cost effective solution as such as wireless networking, where more than one building separated by some distances. Such installations may require more access points, which perform the operations of routers and bridges in order to connect the LAN to the wireless connection. The access points are allowed to communicate by the wireless connection directly and thus the LANs interconnect. Such distribution of interconnecting the access points wirelessly is known as Wireless Distribution System. Different roles may be thus performed by these access points as; remote BS, relay or a main access point. The relay base station has the functionality of forwarding/relaying information between relay stations, clients, to a main or another relay station. A main base station on the other hand is connected directly to the wired Ethernet. Connections from wireless clients are accepted by the remote base station and are then passed to the main or the relay station.

Same radio channel, and shared WEP keys should however be used by all the base stations.

Among many other challenges which tackle the wireless network implementation, security is one of the most critical challenges. Insecurity is an inherent feature of wireless networks. In order to handle security related weaknesses of the wireless network, a standard, WEP (Wireless Encryption Protocol) was designed. However, the standard is yet incapable of fully securing the network and as the networking technologies keep developing, new deficiencies keep arising. An alternative could be to use a VPN (Virtual Private Network), however, it may not work well for all types of devices and is limited in scope. For example, VPN clients are not supported by several PDAs and many other handheld devices.

[] describes a secure solution to be as;

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ An authentication entity that authenticates all wireless access requests.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ It does not itself involve any application that requires authentication.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Should be compatible across devices and is not based on specific platform.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Any packet inspection methods, firewalls, should not be used by the solution, which interfere with traffic performance.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ All forms of network traffic should be allowed by the solution.

ï‚·ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ ï‚ Administrators should be supported to identify users.