Abstract

Network administrators have more tools and information at their disposal now, than ever before. Networks are changing every day. Users are always demanding faster connections, more stability, reliability and more features. Administrators need to keep this in mind from the initial planning stages of the network to ensure scalability, performance, and end user satisfaction. There are plenty of design concerns and this paper will address some of them and attempt to provide a solid reference to those seeking solid network design principles.

Bandwidth Managers

Bandwidth mangers can be hardware or software based. After implementing the hardware, the software gives the users the ability to break down the traffic based on set criteria. Similar to content switching, the users now has the ability to sort network traffic by IP address, port number, or even custom parameters. Classification schemes vary from product to product, the research in this field is advancing at a rapid pace and soon optimization algorithms can become uniform. Today bandwidth management is quite complex and only for experienced network administrators. Handling TCP traffic requires the examination of each packet while requiring each side of the TCP connection to be fooled into thinking there is a long delay while the bandwidth managers handles the traffic so they don’t retransmit the packets.

Restoration and Disaster Recovery

Sometimes, even the best laid plans falter and the network will go down. The problem can be simple or complex, but is often difficult to diagnose. Some network topologies conform to good design protocols and in the unfortunate even of a cut cable or outage, can self heal. Others are not quite as well designed, and the problems can bring business to a halt. A wise business accounts for these possible scenarios when designing the network to laying the cable to future construction where a cable cut is possible. Business should have a detailed restoration plan as well as the software to successfully restore and repair the network. Additionally, network administrators need to be ready to come in anytime to fix the problem. Network outages can mean lost productivity or revenue for the business. Some of which is time critical (i.e. Amazon.com around Christmas) and the revenue cannot be replaced, damaging the firms reputation and possibly shifting customers to a competitor.

High Availability Networks

While all networks are important, some are mission critical and must be kept up at all times. 3Com has set forth a good definition of a high availability network with the following characteristics:

Resiliency — The ability of network and other devices to apply preventive safeguards as a way of heading off degradation or failure.

Redundancy — The presence of multiple units of critical hardware devices, such as network interface cards (NICs), switches, routers, and other equipment and components.

Manageability — Network management is the manager's window into network availability; it is essential for evaluating and tuning the network's availability.

With this in mind, 3Com also prescribes some very intrusting solutions. A Location-Based Strategy is their solution where the availability of key network components is maintained at critical locations. The data center is a point for critical business applications and should be upgraded with redundant systems to ensure optimal performance and reliability. The building or campus backbone also must be protected. These are high bandwidth links that connect to everything from data centers to desktops. If a backbone fails, most users will be unable to gain access to the network. 3Com recommends the inherently resilient ATM protocol for backbone technology. The WAN interface is another section that needs to be guarded. E-commerce relies heavily on the WAN interface, and it is critical for building truly highly available networks. Load balancing and link redundancy can be used to alleviate the problem.

Improve Performance

There are many methods to improve network performance. Load balancing, clustering and traffic management systems are a few. These can be hardware and/or software based, but will probably include a mix. Network administrators can even design customer applications that work for their specific network. Intel is offering a new network processor with should revolutionize the industry and significantly speed up some network. There have been methods to improve network performance around for as long as networks themselves, but only recently has the subject been researched in depth and solutions derived. New methods like LVS and content switching will have a great impact on the industry and could prove to be a boon for any company knowledgeable to take advantage of the opportunity.

Network Management Systems

Network management is crucial to high available networking. Managing a network allows the administrator to trouble shoot, optimize, or generate reports about the network performance. Some sophisticated network management tools include:

· Remote Monitoring Software - installed on the switch allows information to be monitored from a remote location

· Management Information Base (MIB) - agents that perform protocol analysis and determine network usage

· Service Level Reports - Describe how the goals were met and provide invaluable clues on how to increase performance in the future.

There are new tools coming out everyday, but most are vendor proprietary and there are few standards. However, progress is being made, and these tools are allowing administrators to “bulletproof” their networks and manage them more effectively and efficiently.

Network Security

Security is a major issue in today’s networking world. Information is key, and ensuring it arrives safely, accurately, on time, and to only the intended recipient(s) is of paramount importance. Sharing information across a many users and machines can leave a firm open to attack. There are many forms of attack and many ways to respond to a successful attack. Companies that are successfully compromised are not quick to share that fact with the authorities, the public, or the competition. If a firm’s system has been compromised, the customers may feel unsecure about future dealing with that firm, now perceived to be unsecure. Competitors will be quick to tout their security over the compromised site. The compromised site should be ready and willing to share information with the authorities to bring justice to the offender. This would also dissuade copycat attacks. The shared information would help more sites become secure. Sharing this vital security information with competitor would create a more secure Internet, increase customer confidence and lead to greater long-term profits. While short term profits may decrease in response to this radical idea, overall the industry will be more secure, customers more satisfied, and new unforeseen opportunities will arise. Network security is very important, and needs to be address at every stage of the network planning, design, implementation and maintenance.

Capacity Planning

There is never enough bandwidth. Users always want a faster and more stable connection. This is where strategic capacity planning comes in. When initially designing a network one must assume the basic infrastructure will be in use for a long time, there for it must be very scalable. One of the major costs and hassles is laying cable. One should understand this and realize that laying new lines will be very expensive, in terms of the actual cost and the opportunity cost lost because of the inconvenience. With this in mind, one must consider four factors when making capacity planning decisions:

User Dissatisfaction: Network loads are dynamic and without proper planning, during peak hours, the increased load may force users to wait too long, decreasing their satisfaction.

Productivity Decrease: Increased network traffic will mean a decrease to productivity. Employees may have to wait too long for their transaction to be complete and other work may suffer. Alternately, they may think there is an error, and send the query over and over again, further clogging the system.

Budgetary Constraints: Funds need to be made available before the problem occurs. This will ensure that it can be scaled whenever necessary instead of fighting for funds from management.

Stability: Early Identification of problem areas and being proactive can increase stability and user satisfaction. Stability problems usually occur during peak loads when your systems are most needed. Proper planning and traffic monitoring are needed to fix this problem.

Conclusion

With the importance of networks increasing, it falls upon network designers to ensure there networks will be able to deliver what their clients are expecting. Using proper design techniques, this can be achieved. Ensuring the network is secure, scalable and meets the goals of the business is achievable, but time consuming and expensive. However, the alternative is worse. Not thoroughly planning or sloppy design will cause nothing but headaches for the administrators and users. Setting aside extra time and capital at the outset should alleviate or significantly reduce these problems. Networks are important, and will continue to be so for the foreseeable future, and ensuring proper design will allow the business to achieve it’s goals and make everyone’s life a bit easier.

Reference:

http://www.nwfusion.com/reviews/0406rev2.html

http://intranets.about.com/compute/intranets/cs/bandwidthmanagers/

http://compnetworking.about.com/compute/compnetworking/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.etinc.com%2Fbwmgr.htm

http://www.ieng.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm

http://www.3com.com/technology/tech_news/highavail.html

http://compnetworking.about.com/compute/compnetworking/cs/qoscapacityplan/index.htm