SERVERS AND COMMUNICATION TOOLS

SERVERS AND COMMUNICATION TOOLS Web Server Software  Web server software, is an additional piece of software that is installed and runs on the server platform, either NT, Unix or some other operating system. At the heart of the software is utility called the HTTP daemon that accepts and processes commands from the browser software running on the server. In other words, when the user clicks a hyperlink on a Web page, a request is sent to the Web server for the page associated with the link. It is the HTTP daemon that responds to the request and sends the results to the client machine. The basic functionality has been built on and enhanced by all of the 100+ software products currently available to run the Web server.   Some of the most popular applications are available as free downloads from the Internet, and often, in some instances offer better functionality and features than many of the commercial products.   Choosing Web server software is not an easy task. There is a vast array of products available, with many different features, and the only way to really make a proper and informed choice, is to actually evaluate the software. In all cases, the server software you are currently running on your server will narrow the choice. If you are a Windows-centric company, then there is little point in fiddling with Unix based products, since you would need to enlist the services of a Unix expert to make it work.   The purpose of your Web server will also narrow your choice. If for example, you desire to trade over the Internet, like an on-line shop, you will need software that provides on-line transaction functionality. Or perhaps you will desire to provide referencing capabilities, for which you will require a built-in search engine.  Software Apache - SSL (Stronghold)  The public domain Apache server runs more Web servers software than any other server software. The commercial version (Stronghold) has been enhanced and improved, and will run on a wide range of Unix platforms, whereas the basic Apache server will run on any Unix system. The main difference between the commercial and basic packages, is the commercial version's inclusion of SSL-2.0, which is a secure connection protocol.  Stronghold has to be downloaded from the Internet (currently at version 3) and unzipped onto the Unix server. The software is installed and run from the command-line interface, which will undoubtedly prove quite daunting for newcomers and the inexperienced alike. However, for those experienced in the use of Unix, this is a relatively simple process.   Apache does not come with any management tools or authoring utilities. To perform these functions, Apache supports Unix compatible scripting tools such as Perl and CGI. Again, these skills remain in the possession of the Unix experts, and not suitable for the average user.    IIS (Internet Information Services)  Microsoft's Web server software is supplied free as part of the server operating system. If comes with any of the more recent members of the Microsoft server family packages, and for the earlier NT server 4.0, it can be acquired free with the NT Server 4.0 service pack. IIS integrates very closely with NT and 2000 versions of Windows, making it a sound choice for administrators already running Microsoft servers in their organisations. Even if you are unfamiliar with Windows Server applications, it is easy to install and configure using the numerous wizards that lead you through the process, step-by-step. Included with the HTTP server, IIS includes Gopher and FTP servers, both also making use of wizards.   Latest versions of IIS see the inclusion of ASP (Active Server pages), an application development environment. This product allows yon to create complex Web sites that combine HTML, ActiveX, Visual Basic scripting and JavaScript. Links to back-end database servers, and support for SQL Server, Oracle, SyBase, Informix, ODBC databases and of course Microsoft access, is also provided.

Server Performance  When running a Web server, it is crucial that the machine hosting your site and the various software components installed, is able to perform well at all times. Granted, there will be times of increased traffic where users of your site will experience slowdown. However, the slowdown must be kept within acceptable limits, otherwise one of two things can happen. The server may fail under the strain of heavy traffic, or users will be so discouraged by the poor performance, that they will seek whatever it is the wish to find elsewhere. The aim of having a website, is to entice as many people as possible, not to drive them away. This is only half of the battle, getting them to stay is another challenge altogether. This is extremely important, particularly if your site provides a source of income, perhaps running an e-commerce application for example. Connection Speed  There are several things that organisations can do in order to maintain acceptable levels of performance, all server-based. A very important aspect of web server performance, is the speed of connection to the Internet. As in all things, cost is a consideration. It is advisable to stretch the budget as far as possible, in order to acquire the fastest connection. The bottom end of the scale is a 56K modem connection. This is totally unacceptable for commercial use. Modems may still have a part to play however, if several are installed and the server software combines the bandwidth of all modems, thus increasing the speed of the connection. This is perhaps acceptable for servers that are not required to handle high volume traffic, however, faster technologies such as ISDN, ADSL or even T1, are a more likely solution.  Hardware Specification  The more obvious means of ensuring good performance of the server, is to ensure that it is loaded with fast resources. The internal components of the machine should again be the best that is affordable. Cutting corners in this area will be terminal. Server machines require as much RAM (random access memory) as possible, with the amount of RAM being directly proportionate to the amount of traffic being handled by the machine. Also, a fast processor is essential, in fact, it might be a worth considering multiple processors. OEM versions of Windows NT can support up to 32 CPUs. This may be rather heavy handed, however, more than one is a worthwhile consideration, again as needs and cash flow dictate. The hard drive is a component often overlooked. The faster data can de accessed on the drive, the faster the user is serviced. Faster drive types should be consider, e.g. SCSI (small computers system interface, pronounced scuzzy). SCSI drives have faster access times and faster throughput, therefore all round better performance. Also, the nature of SCSI drives is such that more dives can be attached to the motherboard than the EIDE variety. This of course amounts to more storage space also, very important for clients who may wish to rent server space or upload sites. Depending on the nature of your business and purpose of the server, the extra space may be useful for storing utilities like programs, drivers, presentations and files, made available as downloads via FTP.  The need for these types of resources is further underlined by the fact that NT server is a resource-hungry platform. Unix systems on the other hand, manage resources more efficiently and requires less.

Mapping  The home directory is mapped to your domain name, for example, if you're Internet domain name is www.buymystuff.com and your files are stored in C:\website\mysite (mysite being the home directory) then browsers use the URL www.buymystuff.com to access files in your home directory. This directory is automatically created when you install IIS then manually configured later by the administrator. This technique can allow your server to host multiple Web sites.

Performance Monitoring A state-of-the-art server machine is not the end of the matter. Keeping tabs on the system is also a very important aspect of running a Web server. This will unsure that any problems with the machine's hardware, software or even the physical connection to the Internet, will show up in the analysis. Data gleaned from monitoring, alerts administrators to problems, and can provide positive identification to the source of the problem also. Management System  In a management system, there is a central suite of software that is dedicated to monitoring the Web server and the network. The software can assess the performance of all related objects on the network, e.g. servers, routers or hubs. A terminal is available that allows the administrator to view the results, called the management system. The central suite of software monitors each object, by communicating with each of them through software agents installed on the objects and collecting statistical information. Installing a management system such as this, means a difficult choice has to be made; which of the different protocols, currently available, should be used?  Management Standards  There are basically two categories that network management systems fall into, those which utilise proprietary protocols, and those which comply with a standard. The ISO (Industry Standard Organisation) defines its management system within the CMIP (common management information protocol) system. CMIP might be the official standard, but the most widely accepted standard with the greatest installed base is the SNMP (simple network management protocol) suite. This was defined by the developers of TCP/IP, the Internet protocol. Other systems are also available, such as IBM's NetView. It has been suggested that CMIP is the most powerful of all the management protocols, and will be widely embraced as the protocol of choice.  Information Gatherers  The agents running on various objects like the server, firewall, proxy, routers, bridges and hubs can possess an area of memory and a processor, to gather statistical information and pass it on to the management station monitor. The monitor polls each agent and retrieves the statistical information that has been gathered about its own performance. Usually the monitor station can present these results in a graphical format on a GUI-based interface. Server Performance Tools  Thus far we have seen by and large the management of the entire network. This is of course very important, since your Web server may well be providing Intranet services to the organisation as well as Web services for the outside world. From the Web server perspective, it is more important to monitor the server. It is the task of the administrator to ensure that the server is operating at its optimum performance, ensuring that there are no problems, bottlenecks, or disasters lying in wait. The best way to look out for these is to run server-monitoring tools on the server, to continually check its status.  As mentioned under the section dealing with Networks, NT comes with a good selection of tools. Other operating systems come with a range of similar tools, or tools can be installed from a third part vendor.  Windows NT includes the following utilities: Network Monitor  This utility is a good tool for finding out what is happening around the server at the packet level of network transmission. It monitors all traffic to and from the server, and can be set to filter the information from a particular node or address Performance Monitor This utility provides comprehensive information on how the server is working, and is the main way of detecting upgrading needs. Its main feature is to display information in a chart form, relating to a particular resource on the server. It supports an impressive list of items from different memory objects, CPU and network traffic, and even more Internet specific items like, CGI requests, connections and file throughput. Server Monitor  This utility provides a way of monitoring the resources being used on the server. This includes a view of shared resources, users connected to the server and which is connected to what resource. Task Manager This utility provides a graphical view of the CPU and memory usage on the server. It also lists current processes and applications running on the server. These representations allow the administrator to assess the performance of the components. Obviously, if they were being strained, then this would indicate the need for upgrading.  Making good use of these utilities, or others like them, will ensure that your server's health is continually monitored. Problems that arise can be  Load Testing Load testing is a technique that allows you to simulate traffic on your server. If you run a mission-critical system, then load testing will help you spot bottlenecks in your system under high stress scenarios, before they happen in the production environment. You can view your system as it handles thousands of concurrent users, before you launch it for the entire world to visit! IT projects are very expensive, so load testing will help you avoid wasting money, by ensuring that your system will cope. Portent provides a family of software options that carry out load testing simulations on your server. Their software is easy to us, comes with an attractive GUI, and is cost effective. The various features allow you to simulate HTTP Gets, CGI scripting, heavy database traffic and queries, among many other features. The Portent Classic version costs $80, while the Supreme version costs $280. There are other versions available, but the cost is not advertised. Perhaps they are afraid of frightening the customers away! Pricing is acquired by e-mailing their sales team direct.  Their Web site contains detailed information about their products, and better still, they provide on-line software demonstrations that you can run in your browser, there is a downloadable version also. The simulation contains attractive and detailed screenshots, with plenty of information, giving detailed accounts about the function of each screen.   Visit their website at www.loadtesting.com

Virtual Directories and Aliases Virtual directories are also a means of making your site more accessible to users and therefore more manageable. If for example, you have a directory on another part of your server, that is not included in the home directory or its structure, it is possible to make it appear to a client's browser as though it were contained in the home directory. As previously mentioned, use of this technique allows directories running on different machines to appear as though they are running on the one server in the one directory. Again, using this technique allows the load to be spread across multiple machines. With more machines doing the job, traffic is handled well, and efficient performance is maintained.  Virtual directories can also be assigned an alias. An alias is a nickname of sorts, which is assigned to a directory. The directory my have a complex path, which will be difficult for users to remember. For example, Intranet users may need to access files stored in the last directory on the following path:   c:\wwwroot\manufacturing\sales\invoices.  This is cumbersome and difficult for users to remember and enter without making errors, so it is possible and advisable to assign an alias to the last directory. For example, Invoices. When the alias is entered into the browser URL bar, the users will be transported to the invoice directory as the diagram below shows. Portability  Portability is an issue that affects many aspects of your domain. It may come to a point were things will have to be moved around in your organisation, for various reasons. Perhaps your server is down, or you are simply upgrading to a newer better machine to cope with an increased load. Your site has to be designed in such a manner that it can be "lifted" and placed in another location. It is important to ensure a certain degree of portability within your site. Will your various scripts, forms, animations, movies, sounds etc, run on a new server platform? Will it perform as reliably as before on an upgraded version of the current platform? There is possibly no way to fully know the answers to these questions, because new hardware and software is being designed everyday, and there is no way that we can legislate for the odd failure.   However, there is still much that can be done. Research and testing is required to be carried out regarding the choice of hardware and software when creating your original site. Knowing what will work and where, often allows us to extrapolate for the future. When designing and implementing your site, a firm eye ought to be fixed on the future, in order that you are able to know, to the best of your ability, what will and wont run across the various technologies. Remember, nothing in computing remains motionless long enough for the dust to settle on it.  Organisation is another key factor. Keeping your site well organised and well documented, will ease the hassle of moving. If your site is ad-hoc in nature, then great difficulty will be experienced when trying to move it, and again, when attempting to reassemble it. Much time will undoubtedly be lost, and there is the possibility that your site may not run the way it once did. FOR MORE INFORMATION CLICK HERE