【正文】 護(hù)主管人員每月應(yīng)檢查維護(hù)作業(yè)。第3章 維護(hù)作業(yè)管理細(xì)則 維護(hù)作業(yè)制度無線寬帶維護(hù)應(yīng)納入大運(yùn)維的匯報(bào)制度。 最高值： 最大性能。迅馳芯片Intel無線網(wǎng)卡幫助中定義的“電源管理”概念：默認(rèn)值： 電源設(shè)置基于計(jì)算機(jī)的電源。客戶端與AP間的認(rèn)證和關(guān)聯(lián)，都是發(fā)生在“切換”“漫游”動(dòng)作后。如果不同的AP設(shè)備發(fā)送相同SSID服務(wù)的Beacon報(bào)文，且對(duì)于同一終端用戶來說，看到的AP RSSI(接收信號(hào)強(qiáng)度指數(shù))也不存在明顯區(qū)別，那么對(duì)于接入終端來說，就存在隨時(shí)切換的可能，也存在著接入“信號(hào)格數(shù)”差1格的設(shè)備，這就是我們常說的“無線網(wǎng)絡(luò)的不穩(wěn)定性是絕對(duì)的，穩(wěn)定性是相對(duì)的”。無線終端連接AP設(shè)備是通過主動(dòng)發(fā)送探針請(qǐng)求報(bào)文(Probe Request)發(fā)現(xiàn)相關(guān)設(shè)備，或者通過被動(dòng)接收AP設(shè)備發(fā)送的Beacon報(bào)文獲得物理空間AP覆蓋信息。 最高值：您的無線客戶端持續(xù)跟蹤鏈接質(zhì)量。 最低值： 您的無線客戶端不漫游。迅馳芯片Intel無線網(wǎng)卡幫助中定義的“漫游主動(dòng)性”概念：此設(shè)置允許您定義無線客戶端為改善與接入點(diǎn)連接的漫游主動(dòng)程度。這包括當(dāng)您更加喜歡的無線網(wǎng)絡(luò)可用時(shí)自動(dòng)選擇并連接到該網(wǎng)絡(luò)。If there are no preferred networks in the list of those available, the WZC service attempts to configure connections to the preferred networks in their configured order. This is done in case the access points for the wireless network are configured to prohibit the beaconing of their network name (SSID).如果在現(xiàn)有的無線網(wǎng)絡(luò)中，并沒有首選網(wǎng)絡(luò)，那么WZC將按照已有的配置順序正常連接。If there are two preferred wireless networks and the most preferred one is not initially available, the WZC service configures a wireless connection to the next most preferred network. When the most preferred network eventually bees available, the WZC service automatically switches the wireless client connection to it after the next scan. 如果有兩個(gè)首選網(wǎng)絡(luò)并且最優(yōu)的一個(gè)還并沒有被使能，那么WZC將在下次可能時(shí)連接這個(gè)最優(yōu)的網(wǎng)絡(luò)。經(jīng)過這樣的步驟以后，WZC將會(huì)保持這樣的連接方式。The operation of the WZC service provides the following: The first time a wireless adapter is added to a puter running Windows XP, the WZC service prompts you with the One or more wireless networks are available message in the notification area, which leads you to select a wireless network by using the Wireless Network Connection dialog box. After you select a wireless network and the connection is successful, the selected network is automatically added as a preferred network, and you are no longer prompted with the One or more wireless networks are available message whenever you are within range of it. 現(xiàn)在我們來回顧一下WZC工作的步驟：首先，WZC在客戶端提示你有一個(gè)或多個(gè)無線網(wǎng)絡(luò)可用，當(dāng)你選擇其一并成功連接以后，選擇的網(wǎng)絡(luò)(SSID)自動(dòng)被添加進(jìn)首選網(wǎng)絡(luò)，那么當(dāng)你下次再進(jìn)入進(jìn)入它的覆蓋區(qū)域，系統(tǒng)將不再提示。For subsequent scans, the WZC service determines if there are any changes in the wireless environment that require switching the connection. If the Windows XP wireless client is already connected to a wireless network and there is no other preferred network higher in the preference list that has not been attempted already, the WZC service maintains the existing connection. If the Windows XP wireless client is already connected to a wireless network but a more preferred wireless network bees available, the WZC service disconnects from the currently connected wireless network and attempts to connect to the more preferred wireless network.在隨后的掃描過程中，WZC自主決定當(dāng)網(wǎng)絡(luò)環(huán)境發(fā)生變化的時(shí)候是否進(jìn)行切換。所以，我們常會(huì)發(fā)現(xiàn)，客戶端會(huì)自動(dòng)連接到一個(gè)可用網(wǎng)絡(luò)。If Automatically connect to nonpreferred networks is enabled, the WZC service attempts to connect to the available networks the order in which they were sensed by the wireless adapter. If all connection attempts fail, the WZC service creates a random network name and places the wireless network adapter in infrastructure mode. After this, the wireless adapter is not connected to any wireless network but continues to scan for preferred wireless networks every 60 seconds. This behavior prevents the Windows XP wireless client from accidentally connecting to a wireless network that does not appear in the list of preferred networks. You are then prompted with the One or more wireless networks are available message in the notification area. WZC服務(wù)將按照無線網(wǎng)卡的感知順序來依次連接可用網(wǎng)絡(luò)。If there are no successful connections and there is an ad hoc network in the list of preferred networks that is not available, the WZC service configures the wireless network adapter to act as the first node in the ad hoc network. 如果連接仍不成功，同時(shí)有一個(gè)點(diǎn)到點(diǎn)的服務(wù)出現(xiàn)在首選網(wǎng)絡(luò)中，WZC將配置無線網(wǎng)卡作為這個(gè)點(diǎn)到點(diǎn)網(wǎng)絡(luò)的第一個(gè)節(jié)點(diǎn)。(enus).aspxHow the WZC service Works無線零配置服務(wù) (WZC)是如何工作的For the initial scan of available networks, the WZC service performs the following process: 對(duì)于初始掃描無線可用網(wǎng)絡(luò)，WZC服務(wù)的工作步驟如下：The WZC service attempts to connect to the preferred networks in the list of available networks, in the preferred networks preference order.WZC服務(wù)嘗試去連接在可用網(wǎng)絡(luò)列表中的首選網(wǎng)絡(luò)服務(wù)，它們是按照一定的優(yōu)先級(jí)來排序的。反之，如果分布式覆蓋AP及其BSS內(nèi)的STA進(jìn)行大流量數(shù)據(jù)傳輸，也會(huì)給其覆蓋區(qū)域內(nèi)的其他AP帶來信道阻塞，從而影響其性能甚至接入。由于相對(duì)距離關(guān)系，其他AP互相之間的干擾相對(duì)較小，但是這些AP都會(huì)對(duì)可以接收到其信號(hào)的覆蓋AP產(chǎn)生干擾，從而影響WLAN覆蓋網(wǎng)絡(luò)的性能。如下面這個(gè)無線環(huán)境顯然不很理想。通過一段時(shí)間的統(tǒng)計(jì)，從圖形中也可觀察此信號(hào)的穩(wěn)定程度。此信號(hào)強(qiáng)度的單位為dBm，一般情況下，信號(hào)強(qiáng)度在75dBm以上可認(rèn)為此信號(hào)較好。見上圖“Signal+”表示至運(yùn)行Network Stumbler軟件以來，此SSID的最大信號(hào)強(qiáng)度，注意此值不是當(dāng)前信號(hào)強(qiáng)度。首先我們先介紹一下常用的查看信號(hào)的軟件Network Stumbler。WLAN系統(tǒng)中每個(gè)信道的帶寬是有限的，其有限的帶寬資源會(huì)在所有共享相同信道的STA間平均分配。這樣就最大可能地避免了樓層間的干擾，無論是水平面還是垂直面都做到無線的蜂窩式覆蓋。但在信道設(shè)置時(shí)要考慮三維空間的信號(hào)干擾，如下圖。當(dāng)某個(gè)無線設(shè)備功率過大時(shí)，會(huì)出現(xiàn)部分區(qū)域有同頻干擾，這時(shí)可以通過調(diào)整無線設(shè)備的發(fā)射功率來避免這種情況的發(fā)生。l 蜂窩式無線覆蓋實(shí)現(xiàn)無交叉頻率重復(fù)使用。蜂窩式覆蓋原則：l 任意相鄰區(qū)域使用無頻率交叉的頻道，如：11頻道 。為了最大程度的利用頻段資源，我們可以使用11；12；8，13；14這四組互相不干擾的信道來進(jìn)行無線覆蓋。在中國(guó)，與歐洲一樣，同樣開放113信道。信道14 是特別針對(duì)日本所定義的，其中心頻率與信道13 的中心頻率相差12 MHz。兩個(gè)信道中心頻率之間為5MHz。如AP使用auto方式注冊(cè)成功后，需及時(shí)對(duì)AP進(jìn)行固化并修改相關(guān)配置，進(jìn)行正確的描述，以區(qū)分AP的安裝位置。大量FIT AP向AC注冊(cè)時(shí)會(huì)用到三層注冊(cè)方式dhcp option 43，但有些時(shí)候AP可以獲取到DHCP地址卻獲取不到option 43下發(fā)的AC地址，此時(shí)可以用PC替換AP進(jìn)行抓包確認(rèn)DHCP SERVER下發(fā)地址時(shí)有沒有成功下發(fā)option 43屬性。 室外FIT AP加大增益天線覆蓋設(shè)備安裝在室外時(shí)，若設(shè)備為非室外型，需保證設(shè)備的工作環(huán)境符合室外安裝的要求（防水、防塵、防雷）或增加室外機(jī)箱，一般室外覆蓋會(huì)用長(zhǎng)饋線把AP設(shè)備與天線進(jìn)行連接，天線通常暴露室外，因此防水、防雷、接地工作一定要按要求完成。建議對(duì)AP進(jìn)行靜態(tài)信道配置，可更加有效更加清晰地對(duì)設(shè)備進(jìn)行管理，同時(shí)也會(huì)最大限度的避免信道干擾。定期巡檢，觀察AP的指示燈是否正常，檢查AP工作溫度及環(huán)境是否滿足要求，盡量做到設(shè)備出現(xiàn)故障前就對(duì)設(shè)備進(jìn)行更換或修理。 FIT AP產(chǎn)品運(yùn)維建議216。（2）能正常連接到AP上并可以得到網(wǎng)絡(luò)服務(wù)，但過一段時(shí)間后發(fā)現(xiàn)上網(wǎng)速度越來越慢，最后導(dǎo)致無法訪問外網(wǎng)，但還仍然連接到AP上。設(shè)備運(yùn)維巡檢及問題處理方式（1）用戶反饋AP信號(hào)弱飄忽不定的故障現(xiàn)象。（6）減少周圍無線干擾源，在允許或可以調(diào)節(jié)的情況下把同頻干擾減少到最小，同時(shí)也要注意周圍是否有無線電微波干擾源，如微波爐、無繩電話等。因?yàn)锳P天線安裝在樓頂時(shí)，由于室外天線覆蓋角度問題會(huì)造成1層與2層覆蓋效果欠佳，這時(shí)可以適當(dāng)調(diào)整覆蓋天線角度或把AP的天線從樓頂下移到3樓位置以改善覆蓋區(qū)域的效果。（3）在AP天線與覆蓋區(qū)域間盡量避免有樹林的遮擋。 非結(jié)合室內(nèi)分布系統(tǒng)（室外覆蓋）的安裝環(huán)境設(shè)備運(yùn)行基本環(huán)境檢查與維護(hù)：（1）定期檢查AP設(shè)備工作環(huán)境溫度與濕度，因室外AP設(shè)備一般工作在復(fù)雜惡劣的環(huán)境下，因此定期檢查AP的工作環(huán)境是為了AP更加穩(wěn)定高效的運(yùn)行。（5）在對(duì)AP設(shè)備進(jìn)行更改配置前請(qǐng)備份AP設(shè)備配置文件，在確認(rèn)AP修改配置并生效后請(qǐng)及時(shí)保存。（3）在portal認(rèn)證模式下，無線客戶端可以連接SSID，但