【正文】 當處理水平網(wǎng)絡時，錯誤判斷將帶來昂貴而持久的后果。但通常只有一個得到正確的機會，因為水平布線的壽命是 10年或更多點。通過對比的方式， PC 機的壽命約為 2 3年，而以太交換機 3 5年。鑒于此 ,正確的選擇水平布線是至關(guān)重要的。 對于 10Mbs 工作，銅 3類電纜很足夠了。 對于 100Mbs 工作，銅 5類電纜是必需的。 對于 1 Gbs 工作，銅 5e 類電纜是必需的。 對于 10 Gbs 的工作，延長工作 50/125μ m 的光纖電纜是必需的。 如果，作為趨向建議，我們也許期待在布線的壽命之內(nèi) 10Gbs 的操作，然而，事實上，水平布線是昂貴的改變，我們應該盡我們所能設法使當前的裝置作為所謂 “面向未來的”。因為改進的銅纜布線提供的解決方案很可能是短暫的，也很可能和光纖一樣昂貴，所以我們需要在所有的新工作考慮提供光纖。如果因為目前的成本問題，在任何給定的項目并不實際安裝光纖，但至少，在布線內(nèi)容中應該預留光纖的空間，以適應未來的應用。一種實現(xiàn)這一沒有鋪設任何實際的光纖的方法就是是使用“ 氣吹光纖 ”導管。這是一種藉以沿著傳統(tǒng)布線的輸送管道安裝光纖的技術(shù)。他們隨后可能會投入使用，通過使用壓縮空氣將光纖吹入預裝管道下到目的地。這具有下列優(yōu)點： 對裝修有最小的干擾； 對大廈的員工正常工作模式有最小的干擾。當 在零碎的基礎上且和現(xiàn)有的線路同行需要或預算許可時， 光纖可以提供額外的帶寬 。它允許將開支推遲。 氣吹光纖是“原始”（直徑約 ）的光纖。它是由預安裝管道保護的免受損壞。它比傳統(tǒng)的由熟悉的塑料護套包裝的光纖電纜更便宜。 如果環(huán)境改變或發(fā)生損壞，光纖的等級可以被改變。老化的光纖能夠快速方便地回收 ,并且被不同的光纖取代。 輸送管道是小的，并且 可以通過傳統(tǒng)的線纜包含進行運載 。損壞的管道可以切去進行修理，并且損壞的部分也可以用新的管替換它。 因為光纖具有成熟的優(yōu)勢技術(shù) ,大大優(yōu)于電噪聲免疫、本質(zhì)電氣安全 ,優(yōu)越的帶寬 能力 ,數(shù)據(jù)高度安全性，通過長距離攜帶數(shù)據(jù)的能力允許在“主干”的拓撲結(jié)構(gòu)中使用，所以它的用途或潛在的用途應該在所有新線纜施工時認真被考慮。 如果歷史告訴我們什么，那就是沒有任何解決方案是“面向未來的”。 外文原文： The Future of Structured Cabling The JHMI Premise Distribution Plan will be consistent with standards specified by the ATamp。T Premise Distribution System and the International Standards Organization39。s Integrated Services Digital Network. This includes wallplates, wire for the horizontal distribution and the voice/data wiring closet modular cross connection equipment.It is remended that wire runs be less than 230 feet from the voice/data wiring closet to the wall station. Horizontal Distribution Wire amp。 Wallplates ATamp。T type D unshielded twisted pairs shall be used. Each voice/data wall station will receive four type D cables. Each 4pair D cable will be terminated in an standard RJ45 (8position) jack so that each wallplate will need to house four RJ45 jacks. Vertical Distribution Wire amp。 Voice/Data Wiring Closets The wiring closets are generally located on each floor of a bui buildings must be evaluated on a casebycase basis since some of the older buildings have limited space. For new buildings, each closet should be large enough to acmodate a minimum of two standard 19 puter racks. Each of the major premiseplans remends mounting electronics in 19 racks. The larger electronic ponents will require full frame puter racks. These racks will support the ISDN, Ether and Token Ring ponents. In addition, cross connection panels will be required for the telephone wiring, terminal wiring, Ether connections and future Token Ring. Two separate sets of cross connection panels will be required. The data wires will terminate in one set of panels and the voice wires in will segregate functions and minimize confusiondue to two separate organizations maintaining the same set of wires.The data wires will be patched into the appropriate rackmounted data hardware (. 3274 controllers, Ether Bridge boxes, etc.) and the voice wires will be patched into the rackmounted voice hardware (where possible). However if needs change, the base wiring plant will be able to support either the voice or the data technology. Modular cross connection equipment provides easier longterm maintenance and reconfigurability. There are many configurations available from third party sources such as ModTap, Nevada Western and Ortronics. At this point, however, it is most likely that JHMI will go with an ATamp。T solution. A minimum of two ThickWire Ether segments (Belden 9880 or equivalent) will be run through each building to the interconnecting basements. Loops should be left on each floor for future instal cable must have readily available access (. not run in conduit) to insure future use. A minimum of one d in each building riser for future data munications use. Sufficient bulk voice munications riser cable should be run to meet the current and projected requirements. Again, the wiring of existing buildings will need to be evaluated with feasibility in mind. In many buildings the basement wiring closet will act as an intermediate distribution frame back to the main wiring frame. Interbuilding links