tailieunhanh - Mạng và viễn thông P43

Tham khảo tài liệu 'mạng và viễn thông p43', kỹ thuật - công nghệ, kĩ thuật viễn thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Networks and Telecommunications Design and Operation Second Edition. Martin P. Clark Copyright 1991 1997 John Wiley Sons Ltd ISBNs 0-471-97346-7 Hardback 0-470-84158-3 Electronic 42 Selecting and Procuring Equipment The preceding chapter described the factors in outline equipment design which are crucial to the success of the network evolution plan. Having a good plan is one thing executing it is another and in this respect the ordering and delivery of the equipment should receive considerable attention. This is an activity often referred to as procurement and it can be carried out very successfully by highly mechanistic management methods. Various project management techniques are available which tackle network design as if it were the input of a procurement process much as raw material is the input to a manufacturing process . In production-line fashion project management techniques lead the project through its design and checking stages and on to ordering installation and testing. However in the same way as a poor raw material has an effect right through to the end product of a manufacturing chain so the defects of a poor network design cannot be made good during implementation. This chapter describes a typical methodology for selecting and procuring equipment starting from the outline equipment design. TENDERING FOR EQUIPMENT Except for some of the largest corporations very few companies that operate networks also manufacture the equipment that goes to make them up everything from personal computer links upwards needs to be bought from other manufacturers. For small pieces of equipment like modems the purchase may be straightforward because a range of items meeting a standard specification say an ITU-T V-series recommendation is available from a number of manufacturers. The purchaser then has time to concentrate on the finer differences size price reliability ease of maintenance etc. of the various equipments and to choose what suits them best. More costly