Previous | Table of Contents | Next |
Daniel A. Kosek
Large-scale WAN conversions are some of the most difficult projects in networking. To make the process easier, network managers can secure corporate backing, carefully document the current and planned networks, and properly prepare their sites.
Perhaps one of the toughest networking jobs is a technology conversion or replacement on a large WAN. Migration of large-scale WANs from one technology to the next is necessary to allow corporations to take advantage of newer data services and transport technologies. ATM and frame relay have changed the face of these networks forever. The scale of a project is inversely proportional to the need to upgrade the larger the network to be replaced, the more the upgrade appears to be needed.
These larger networks have often been in operation for many years. A switch to newer equipment allows corporations to take advantage of the advancements available in equipment today. Unfortunately, the corporations that can typically gain the most benefit from this type of change seem to be paralyzed in respect to doing a full-scale conversion.
The most prevalent reason for this paralysis is the network that is in place. For example, many companies have operated for more than 15 years using one exclusive network service, such as IBMs SNA. To say the network is fine because SNA operates acceptably shows limited vision. Todays networks include PCs, UNIX workstations, Windows NT, Novell, and Macintosh machines operating companywide. Even LAN applications such as cc:Mail and Lotus Notes indicate the evolution of corporate computing needs. Most IT projects have moved to client/server applications rather than mainframe development.
Newer products and services require a LAN that offers a routable protocol such as IP or IPX. Although such a network is more efficient than SNA for running new applications, it actually does little to replace SNA in many areas. These products must coexist on the corporate WAN in a tolerant manner. A corporate network manager cannot rely on past network performance. Network managers must understand the impact new service requirements demand from the network and the time frame in which they will be delivered.
Another reason for paralysis during a WAN conversion project is fear of change. The politics of changing network technologies are almost totally responsible for most delays in the application of new WAN technologies. For example, a large corporation in the transportation industry had just selected new WAN technology when a major outage occurred in the LAN. The vendor of the WAN equipment used the outage to create great worry about what might happen if the company replaced equipment. The vendor took the exaggerated message higher and higher into the organization until a senior vice-president vetoed the upgrade of the network, fearing the possibility that additional outages might happen.
A poorly managed network conversion results in an ineffectual network. Network managers should follow the same rule as a trim carpenter finishing houses: measure twice, cut once. The following sections discuss several areas that are key to a successful conversion.
Corporate buy-in for a project is a must. The lack of corporate agreement is typically the main cause of the fear that stands in the way of many network upgrades. This is why it is important that corporate management be knowledgeable about the facts concerning a potential upgrade, especially in geographically dispersed companies.
Management, including regional and site managers, should participate in the planning and conversion of the network. The network manager should try to avoid setting any unrealistic expectations. The corporate management team should understand that there will be service outages, but that the plan is designed to keep them to a minimum.
If sites are being converted on the weekends, a member of the conversion team should be available to test voice and data port connections once they are moved onto the new system. One of the main concerns in large companies is other projects competing for the same personnel and possibly already creating outages.
There should be a common schedule, available throughout the company, that documents the scheduling of each competing project. Then not only the conversion but all work related to the project can be scheduled. Some corporations operate around the clock; in these cases there is no good time to be out of service. The slowest business hours must be determined before work is scheduled.
IS personnel should be ready at all times for the possibility of emergency troubleshooting. Project leaders should be informed right away if troubleshooting has started.
A clear understanding of the current network services supported is required to properly complete a migration or technology replacement project. Current detailed data on the network is an absolute necessity. After the information is collected, it must be verified, which may require a number of people at various sites performing a physical check of cables connected to the equipment.
During the verification process at one company, more than 300 connections had either been disconnected or were actually unused. Also, about 110 new connections had been added. Because the new equipment was modeled using the connection counts prior to this verification process, the new equipment orders were in error. There was also an active T1 line that someone had issued a disconnect order for. If the company had continued to pay for that line, hundreds of dollars per month would have been wasted.
The process of verification is actually an audit of the physical network. This audit provides a current snapshot of the network for comparison with what was ordered for the new network. This protects the new installation from having too many or too few ports of the correct type.
One company ordered all high-speed data circuit cards with V.35 interfaces for their conversion, which is typical. However, the audit revealed the need for several RS-449 ports. The ports were for a small videoconference setup between several division locations and the companys headquarters for the top executives daily conference session. Omitting these ports may have cost the network administrator his job.
Once all of the network information is collected, it should be formatted so that it is highly portable. Many companies like to use a spreadsheet. The resulting files can be imported to database programs should the company decide to track the network in the future. Drawings of the network should be created in a file format that is standardized within the company.
All of the files should be stored as data where there is easy access. Although a subdirectory on a server is acceptable, an intranet server is best. It does not take long to set up a Web page and store documents, pictures, and charts as files to be downloaded. Users can download them as needed. This online information system should include lists and drawings, as described in the following sections.
Previous | Table of Contents | Next |