Technological advances over the years have driven the manufacturers of information technology products and systems to add “plug & play” features into their systems as much as possible. The industry direction has been to lower the level of technical knowledge/skills required for system installations and configurations. However, the by-product of this has been to add a tremendous amount of overhead into all aspects of networking.
The most obvious overhead comes in the form of the amount of hard-drive space and system RAM now required on workstations and other subsystems. This overhead extends well beyond the boundaries of the traditional workstation. Routers now require additional RAM in order to support standard feature sets within a given Internetwork Operating System (IOS). A standard system configuration file, whether it is a Microsoft System Registry or a Cisco Running Configuration, has grown in both size and complexity in recent years. This increase in complexity is in direct proportion to the increased desire to make these systems integrate into existing networks with the minimal of amount technical expertise required (i.e. plug & play).
Managers, engineers, and technicians must understand the impact of “plug & play” on their integrated systems (networks). Not only have the bandwidth requirements increased, but also the communications processes between components (along with the complexity to manage these processes). Some manufactures establish their default configurations to give customers as much performance from their systems as possible. Others configure their defaults attempting to provide a system that is as stable as possible. Here are two examples of default plug & play configurations that appear in today’s switching technology:
1. Some switches enable Spanning Tree on all ports by default. This eliminates the potential for bridging loops within the environment. Bridging loops are created when redundant layer-2 paths exist between a source and a destination.
If these redundant paths are both forwarding data at the same time, the same data may then be circulated (looped) between these 2 paths without being removed from the network. Spanning Tree has been developed to eliminate this possibility by disabling one of the paths as long as a “better” path exists. The cost of having Spanning Tree enabled is that it takes Spanning Tree approximately 30 seconds to calculate the “best” path whenever a port is activated (whether any redundancy exists or not). Dynamic addressing techniques, such as IPX and DHCP, will often time out before Spanning Tree is able to complete its computation and forward data through a given port.
2. Other switches have Spanning Tree disabled on all ports by default. This allows clients to acquire a dynamic address as soon as a port is activated. However, if a redundant path is established, whether by design or by accident, the entire network segment may crash.
It is vital for IT departments to understand the plug & play nature of systems within the industry regardless of what layer of the OSI model that system operates at. Although the new technology allows for easier and faster equipment deployments, they may be sacrificing network performance and/or reliability. Departmental standards must be developed (and enforced) to insure optimal system configurations, thus minimizing overall network complexity. These standards must be developed based upon a thorough understanding of the technology and the systems installed on a network. Additionally, by having well defined and well-documented departmental standards, IT organizations will have a vital tool to assist them with network stabilization and recovery procedures.
WEBNET Communications, Inc. specializes in proactive network analysis. Our proactive services include Network, Application and Client Evaluations, Network Standardizations, and Network Documentation. Additionally, we offer services to include emergency response (as available) and on-site analysis and methodology training. For additional information e-mail us at: services@webnetcomm.com
