Logical & Physical Design - Ntc 410

Logical and physical designs are guidelines as to how networks should operate and serve a business. Logical design mostly involves the IP structure of the network, for example a, b, or c addresses in case of wireless networks. Logical designs also look at sub netting, based on how many desktops are involved in that environment. The physical design on the other hand will involve the topology that will be used to determine the network. This involves things like Ethernet, fiber, ISDN and type of design to be used i.e. star or linear designs.

Logical design has to have a blueprint for security which provides layers of security among the framework stages. Security is implemented at the infrastructure layer, appliances layer, service control layer, and applications layer. Each layer has intelligent, scalable security services in every platform that will involve routers, switches, and other devices. The application layer will incorporate both security functionality and critical security protocols.

Information security policies standards and procedures are implemented during the logical design phase, as a way to underpin the security and the well being of the network. The policies act as the foundation, the bottom line, of information resources within the organizations' network. Design of the network architecture also comes into play during the logical planning phase as a way to map out structural areas within the network's location for example the office building that would have access points to resources like printers, scanners etc. The main difference between logical and physical designs is that in the logical design planning of continuity is a major issue as it involves reevaluating, the strength of the network and back up resources. Planning of continuity is a form of business tool that keeps a business operational network infrastructure running through disaster. In logical design incident response planning is a necessity as it prepares the organization for the inevitable such as system crushes or naturals disasters. The logical design consists of clients and services, mapped into zones. Device types that provide network connectivity and security are mapped in with the logical network design for function ability. The design has to be flexible in order to meet the end user's needs over time. The diagram below illustrates a logical design of an office network.

The physical design of the network deals with the topology of the network mainly an ISP (inside plant) or OSP (outside plant). When mapping out the physical design considerations such as the type of cable used is determined by what kind of buffer the network will require depending on the size of the physical area. Physical security issues are a common concern as in the logical design side. Security measures are limited if a hacker or an unauthorized person has physical access to a switch, router, firewall or any other device on the network. Physical design looks at who has access or control to network facilities, physical access to data centers, and physical PC threats.

Hardware layout is a part and parcel of physical network design, determining where PC's, routers, switches, hubs, and printers are located in a physical environment like an office. Layout also brings