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California Educational Data Processing Association |
The DataBus - Vol. 37, No. 4
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Commercial industry and educational institutions face many similar challenges in their current trend towards heavy multimedia usage. Both environments can require the movement of large chunks of data over a shared network. Northrop Grumman has been especially challenged over the last three years as the consolidation of the aerospace industry has resulted in the merging of three other companies with the Northrop Corporation. The new company went from a half dozen plant locations to over a hundred! The people in these locations required access to common corporate data, as well as access to other employees across the street and across the country. All forms of electronic communication were required by these diverse groups: voice, video, e-mail, interactive collaboration, Web and file transfer to name a few. So, as you can imagine, a cost effective infrastructure design was a critical requirement. The following is a case study of a solution that Northrop Grumman has embraced that has relevancy to demanding education communication requirements.
In an effort to take advantage of new and cost effective technology, Northrop Grumman has decided to utilize SMDS, or “Switched Multi-megabit Data Service”. This revolutionary new service provides faster, money saving and effective means for networking and transporting large amounts of data. In addition, SMDS offers a wide variety of options, such as faster service and addressing features. Most importantly, however, SMDS has multimedia capacities, having the ability to carry voice, video and data simultaneously with a high quality of service. According to network engineering manager Marty Keller, SMDS is a natural transition from private line hybrid networks (used previously) to future services such as ATM, or “asynchronous transfer mode”. because like ATM, it uses cell relay with a 53 octet cell. SMDS is an exciting new service that has many specialized features and important benefits. Subscribing to this service will be beneficial to Northrop Grumman in a multitude of ways.
Previously, private line hybrid networks with T1 technology were used to transport data. Many sites all over the United States were used as connecting points for data transportation. However, there are several problems with this type of networking. First of all, it can only transport 1.536 megabits per second. Due to priority deadlines and increasing amounts of data, information needs to be transported at a faster rate. Second, this type of networking is hardly cost effective. Similar to a landline phone situation, Northrop Grumman must pay for service on a monthly basis. Even when the system is not being utilized, the end user is still being charged. Further, the cost cannot be abolished until the T1 line is removed. SMDS offers workable solutions to these and other problems.
Finding a new means of transporting data was first attempted by the Working Group IEEE P802.6 within Bell Laboratories. Following the breakup of the Bell System, Bellcore (Bell Communication Research) continued the development. The basic concepts of SMDS were finally developed around 1986 (Klessig and Tesink, 1995). In other words, it operates according to a “cloud theory.” Information is sent out, and is transported to any given receiver without having to connect to a landline site. Instead, it is transported in or out, and analyzed further within the SMDS systems.
There are many beneficial features of SMDS that were not present in past services. First of all, end users only pay for the amount of data actually received. Unlike former data transport systems, SMDS does not charge fees when the service is not in use. Clearly, this is much more cost effective to the company. Specifically, as Keller claims, using SMDS will result in an approximately 20% savings to Northrop Grumman. This will result in a $1 million savings per year. A second benefit is that peak bandwidth to any given site (determined by the access line and SMDS port) can increase or decrease in incremental jumps. As opposed to the rigid capacity levels of past services, SMDS offers access classes to meet bandwidth needs for rates that are greater than T1, yet less than full T3, which has the capacity of 28 T1s, or 44.736 megabits per second (Pacific Bell User’s Guide, 1995). Subscribers can decide the amount of transport they need, and SMDS will react accordingly.
A third benefit of SMDS is that it uses cell-based technology. As previously mentioned, this type of technology plays a major role in the inner workings of ATM. Since the adaptation of ATM is a future networking goal due to its ability to handle multimedia (voice, video and data) information with anticipated high quality, it is helpful to be exposed to some if its features beforehand. A fourth benefit of SMDS is its screening and control options. As Northrop Grumman works with and has access to important and often classified information, it is of utmost importance that these documents be protected. End users of the service are able to make up member lists that allow and/or disallow specific addresses from sending or receiving pertinent documents. When information is sent out or tries to be received, SMDS switches screen the addresses involved to insure that there is proper authorization. If the addresses are not authorized to work together, the file will be dropped. This feature also helps authenticate against fraudulent activity. An unauthorized user is unable to hack into the system to gain access to any documents. Finally, a fifth benefit of SMDS is that it has been described as being user friendly and easy to use. Although SMDS provides many interesting benefits, there are also some potential problems that might serve as temporary obstacles to data transportation. As pointed out by Keller, if the pipeline fails for any given reason, it may be difficult to achieve a connection. Fortunately, however, there are alternate routes by which documents can travel by. A second possible obstacle is that if the sender or receiver address is incorrect, the file will be dropped (Pacific Bell User’s Guide, 1995). However, this problem is present in almost any application, including electronic mail and faxing. Therefore, this problem is not major, and can be corrected by having accurate addresses.
Because ATM will not be available for several years due to extremely high costs and lack of standardization across the world and the industry itself, it is necessary to use another service--one that is similar to ATM but does not have its present faults. In addition, a new service must be an improvement over the obstacles of previous ones. Clearly, SMDS is a service that meets both of these criteria. It appears to be an excellent service, one that has many benefits without many problems. By subscribing to SMDS, Northrop Grumman is likely to reap benefits that will service to better the company as a whole.
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