电脑设备连接器 东莞皆瑞鹏 网管员技巧 10种方式应对网络出现的问题

电脑设备连接器 东莞皆瑞鹏 网管员技巧 10种方式应对网络出现的问题 网管员技巧 10种方式应对网络出现的问题 [导读]网络故障是在所难免的，重要的是应快速隔离和排除故障。网络维护人员应该配备相应的工具和相应的知识，以便及时、有效的找到和解决问题。本文讨论了网络技术人员和工程师经常遇到的十个令人头疼的问题。先 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 问题，然后讨论使用何种工具来帮助查找和进行故障隔离。旨在起一个抛砖引玉的作用。 网络故障是在所难免的，重要的是应快速隔离和排除故障。网络维护人员应该配备相应的工具和相应的知识，以便及时、有效的找到和解决问题。本文讨论了网络技术人员和工程师经常遇到的十个令人头疼的问题。先分析问题，然后讨论使用何种工具来帮助查找和进行故障隔离。旨在起一个抛砖引玉的作用。 问题1:逮捕物理层的滥用者 -用户抱怨-不能登陆或时断时续 -症状-只影响一个工作站，而该站原先没有问题 -查找问题: 电缆终端链路太长。用户每天都移动，弯曲，连接和切断网络终端(尤其时膝上型笔记本电脑)。廉价的电缆测试仪就能检查这种问题。在你能确切地说是电缆的问题之前，通常首先考虑不是电缆的问题。这需要使用网络测试工具来证明本地网段的健康状况是否良好，集线器端口功能是否正常，网卡及其驱动程序工作是否良好。最后，检查网络互连设备是否有问题。只有此时，你才会知道为了孤立有问题的终端，断开的连接器或是接地回路等问题该从何处着手测试电缆。在铜轴线网络中，搜寻在同轴“T型头”和网卡之间的断头，在UTP网络中，连续运行仪器图测试功能，不断扭动终端以识别接触不良或短路。 -解决问题: 更换工作站连接电缆，更换损坏的连接器，或者必要的话停止使用水平电缆。再次全面检查处理过的电缆。 问题2:快速以太网比升级前的以太网还慢 用户抱怨-10Mbps的以太网速度慢，升级为100Mbps快速以太网后甚至不能连接上网。 -症状-影响新工作站或升级的工作站连接上网。 -查找问题: 对于UTP5类非屏蔽双绞线，用电缆测试仪测试其是否符合对应100Mbps传输速率的EIA/TIA-TSB67标准。某些在10Mbps以太网工作正常的电缆链路因为近端串扰太大在100Mbps以太网就不能正常工作。信号耦合到邻近线对引起高频信号传输失败。将UTP的线对分开甚至会使网络在达到一定流量时瘫痪。 rotary master common neurological disease pathogenesis, clinical manifestations, diagnosis (localized and qualitative diagnosis), differential diagnosis and therapeutic principle. 2. basic requirements (1) number of diseases and cases: the number of disease cases (?) 20 30 cerebral hemorrhage cerebral infarction after subarachnoid hemorrhage: report of 5 5 of encephalitis meningitis in 5 10 10 3 migraines Parkinson's disease epilepsy sclerosis multiplex more than 5 2 spinal disease Guillain-Barre (Guillain-Barre) syndrome in 10 single neuropathy or multiple weeks Surrounding nerve 5 (2) basic skills required: name cases (?) standard full neurological physical examinations and locate 60 waist size 10 reading 20 EMG-EEG reading 20 skull and spinal CT reading 80 head and spine MRI reading 80 Department of Neurology ... (2) clinical knowledge and high skills: basic standards on the basis of further a high standard of inflammatory and degenerative diseases of the nervous system in pathogenesis, clinical presentation, diagnosis, differential diagnosis and therapeutic principle. Familiar with common neurological diseases such as encephalitis, epilepsy, EEG; grasp the imaging of inflammation and degeneration of the nervous system, as well as the results of Transcranial Doppler examination of clinical significance. (3) foreign language, teaching, research and other requirements: can read professional foreign language documents and perform simple medical English -解决问题: 更换或停用不能连接的链路，故障清除后再全部测试处置过的链路。 问题3:无效的看门狗 -用户抱怨-不能连接Novell网络的Netware远程服务器 -症状-影响本网段内与服务器相连的所有工作站 -查找问题: 检查网段的健康状况，注意观察其利用率，碰撞，错误帧和广播帧水平。此时可观察到大量的碰撞或错误帧，该碰撞或错误帧可引起客户机和服务器之间“Hello”帧出现延迟。在某一指定的服务器所在的远端网段重复此测试。如果两个网段都出现空白，用网络测试仪向路由器中的SNMP代理查询，检查两个网段之间的路由表。确定该路径不存在拥挤问题。为了有效地使用资源，在看门狗允许的时间内如果客户机对“Hello”帧无反应，则Novell服务器会将该客户机注销。 -解决问题: 简便地方法时改变看门狗时延地参数，将Novell服务器中的该参数改大。如果情况有所改善，则可确定为引起帧丢失的原因，纠正看门狗延时帧计时器的参数。 问题4:刍菊链效应 -用户抱怨-网络服务变慢 -症状-影响某个以太网段的所有用户。网络服务(访问服务器)变慢，但与所连接的某的服务器无关。 -查找问题: 在高峰时段将网络测试仪连入集线器，运行网络健康状况测试。此时将会观察到大量错误帧。在10BASE-2网络中，错误帧的类型归类为“延迟碰撞”。在10BASE-T网络中帧错误的类型归类为典型的帧校念序列错误(FCS错误)，随着网络用户的增长，新增加的集线器通常与原来的集线器形成效应。 -解决问题: 统计一下任意两个网络设备之间经过的中继器的数量。在10Mbps以太网中不应超过4个，在100Mbps快速以太网中不应超过2个。如果数量超标，则按以太网的标准修正网络拓扑结构，然后再看错误帧是否还出现。 问题5:IP网络管理者的报应 -用户抱怨-一个工作站间隙性出错，不能登陆或者不能访问远端服务器 -症状-只影响一个工作站，通常在增加、移动、变更工作站后出现此问题 rotary master common neurological disease pathogenesis, clinical manifestations, diagnosis (localized and qualitative diagnosis), differential diagnosis and therapeutic principle. 2. basic requirements (1) number of diseases and cases: the number of disease cases (?) 20 30 cerebral hemorrhage cerebral infarction after subarachnoid hemorrhage: report of 5 5 of encephalitis meningitis in 5 10 10 3 migraines Parkinson's disease epilepsy sclerosis multiplex more than 5 2 spinal disease Guillain-Barre (Guillain-Barre) syndrome in 10 single neuropathy or multiple weeks Surrounding nerve 5 (2) basic skills required: name cases (?) standard full neurological physical examinations and locate 60 waist size 10 reading 20 EMG-EEG reading 20 skull and spinal CT reading 80 head and spine MRI reading 80 Department of Neurology ... (2) clinical knowledge and high skills: basic standards on the basis of further a high standard of inflammatory and degenerative diseases of the nervous system in pathogenesis, clinical presentation, diagnosis, differential diagnosis and therapeutic principle. Familiar with common neurological diseases such as encephalitis, epilepsy, EEG; grasp the imaging of inflammation and degeneration of the nervous system, as well as the results of Transcranial Doppler examination of clinical significance. (3) foreign language, teaching, research and other requirements: can read professional foreign language documents and perform simple medical English -查找问题: 先排除用户是否有帐户和安全设置方面的潜在问题。让用户登陆并且试图从另一个工作站重复这一操作。如果成功，则可以用网络测试仪从用户端到服务器之间的链路状况。然后测试网卡，检测硬件和驱动程序的功能和状况。如果没有问题则检查IP设置，确定用户的IP地址是否有效或者是否有重复的IP地址。确定本网段的子网掩码和路由器默认地址是否正确，DNS服务器(如果有)地址是否专用。如果一个新工作站的IP地址与打印服务器的 IP地址设置重复，将会把每个人的打印工作指向该新客户机。 -解决问题: 改为合适的设置，然后重启工作站 问题6:光纤错觉 -用户抱怨-整个网络变慢 -症状-影响所有连接到网段上的工作站 -查找问题: 在正常的网络使用时段，将网络测试仪连接到集线器，在光纤连接的两端产生流量，测试健康状况。在某一时刻断开或接上光纤，每当光纤连入网段时，就会观察到大量的错误帧。劣质的光纤链路连接会在其附属的网段中产生大量垃圾帧，迫使工作站重发帧，网络速度变慢。 -解决问题: 清洁或重新安装好光纤连接器，复位所有的连接器，再次检查网络健康状况，此时应该只有少量的错误帧。 问题7:奇怪!难道电缆在夜间受到过撞击? -用户抱怨-不能连接上网或不能登陆 -症状-网段上只有一个工作站能上网 -查找问题 断开工作站的连接电缆，接上网络测试仪，注意从集线器上检测不到连接信号。运行电缆测试，查看从办公室到配线间之间的电缆是否开路。如果不正常，将工具设置在音频发生器位置，从配线间用音频探测器查出与办公室对应的电缆，通常情况下，在配线间有变动时，电缆线索会受到推挤和碰撞，引起连接器脱落或松动。 -解决问题: 重新插好工作站和工作站和集线器之间的电缆连接器，查看连接信号指示灯是否发亮，确定用户是否能上网。 问题8:“病人”的心还在跳吗? rotary master common neurological disease pathogenesis, clinical manifestations, diagnosis (localized and qualitative diagnosis), differential diagnosis and therapeutic principle. 2. basic requirements (1) number of diseases and cases: the number of disease cases (?) 20 30 cerebral hemorrhage cerebral infarction after subarachnoid hemorrhage: report of 5 5 of encephalitis meningitis in 5 10 10 3 migraines Parkinson's disease epilepsy sclerosis multiplex more than 5 2 spinal disease Guillain-Barre (Guillain-Barre) syndrome in 10 single neuropathy or multiple weeks Surrounding nerve 5 (2) basic skills required: name cases (?) standard full neurological physical examinations and locate 60 waist size 10 reading 20 EMG-EEG reading 20 skull and spinal CT reading 80 head and spine MRI reading 80 Department of Neurology ... (2) clinical knowledge and high skills: basic standards on the basis of further a high standard of inflammatory and degenerative diseases of the nervous system in pathogenesis, clinical presentation, diagnosis, differential diagnosis and therapeutic principle. Familiar with common neurological diseases such as encephalitis, epilepsy, EEG; grasp the imaging of inflammation and degeneration of the nervous system, as well as the results of Transcranial Doppler examination of clinical significance. (3) foreign language, teaching, research and other requirements: can read professional foreign language documents and perform simple medical English -用户抱怨-在网络繁忙的高峰期访问网络的速度很慢 -症状-个别网段的所有工作站对不论是本网段的服务器还是其它网段的服务器都无反应。 -查找问题: 在高峰时段将网络测试仪连接到该网段。运行该网段的网络健康测试，注意网络的利用率、碰撞、错误帧、广播帧的状况，此时可能看到平均碰撞率不正常，观察到的流量中可能有高达50%是碰撞帧碎片。这是帧信号收发错误——SQE(Signal quality error)的表现。“心跳”信号被不经意地停留在“博”的位置。 -解决问题: 定位网络中每一个信号收发者。检查SQE开关是否位于“关”的位置。此信号用在早期的10BASE-5以太网中，新的以太网设备已不再使用。 问题9:可以连接，但不能登陆 -用户抱怨-不能登陆到欲连接的服务器 -症状-问题通常在新安装或重新设置工作站后出现，但仅限于一个工作站 -查找问题: 断开工作站连线，接上网络测试仪，执行IPXPing或者在取得服务器列表后来检查配置的哪一层 802.2)。现在可以测试网卡，检查安装和运行程序是否正确。的网络协议。注意帧的封装类型(例如 还要注意检查网卡绑定帧的类型(比如802.3)。两个帧类型要匹配，如果服务器和工作站运行的帧类型不同，则不能连接上网。 -解决问题: 用Editor打开工作站的NET.CFG,修改其中一行:将FRAME-ETHERNET-802.3改为FRAME-ETHERNET-802.2之后将工作站连接上网，重启。检查服务器连接状况。 问题10:莫名其妙得间歇性连接中断 -用户抱怨-服务速度太慢，连接间歇性中断 -症状-问题仅再一个网站上出现，与正在访问的代理服务器无关。 -查找问题: 断开网站，接上一个具有流量发送(此为诊断过程的一部分)功能的测试工具，检查网络的利用率，碰撞和错误帧水平，确定网络是否健康。若仪器检测通过而只是网站时通时断，则表明是典型的物理层故障。进行电缆链路测试(包括用户连接电缆)，此时长度测试可能显示电缆超长(UTP电缆为100米，铜轴电缆为185米)。超过IEEE规定的允许长度，着将会引起局域网内的传输信号严重衰减。 -解决问题: rotary master common neurological disease pathogenesis, clinical manifestations, diagnosis (localized and qualitative diagnosis), differential diagnosis and therapeutic principle. 2. basic requirements (1) number of diseases and cases: the number of disease cases (?) 20 30 cerebral hemorrhage cerebral infarction after subarachnoid hemorrhage: report of 5 5 of encephalitis meningitis in 5 10 10 3 migraines Parkinson's disease epilepsy sclerosis multiplex more than 5 2 spinal disease Guillain-Barre (Guillain-Barre) syndrome in 10 single neuropathy or multiple weeks Surrounding nerve 5 (2) basic skills required: name cases (?) standard full neurological physical examinations and locate 60 waist size 10 reading 20 EMG-EEG reading 20 skull and spinal CT reading 80 head and spine MRI reading 80 Department of Neurology ... (2) clinical knowledge and high skills: basic standards on the basis of further a high standard of inflammatory and degenerative diseases of the nervous system in pathogenesis, clinical presentation, diagnosis, differential diagnosis and therapeutic principle. Familiar with common neurological diseases such as encephalitis, epilepsy, EEG; grasp the imaging of inflammation and degeneration of the nervous system, as well as the results of Transcranial Doppler examination of clinical significance. (3) foreign language, teaching, research and other requirements: can read professional foreign language documents and perform simple medical English 在链路中增加中继器，使电缆长度限制在允许的范围内。另一个办法就是用光纤代替电缆或铜 轴线。 总结:从以上例子可以清楚的看到，为了查找通常的网络错误，配置合适的网络测试工具是非 常必要的。 rotary master common neurological disease pathogenesis, clinical manifestations, diagnosis (localized and qualitative diagnosis), differential diagnosis and therapeutic principle. 2. basic requirements (1) number of diseases and cases: the number of disease cases (?) 20 30 cerebral hemorrhage cerebral infarction after subarachnoid hemorrhage: report of 5 5 of encephalitis meningitis in 5 10 10 3 migraines Parkinson's disease epilepsy sclerosis multiplex more than 5 2 spinal disease Guillain-Barre (Guillain-Barre) syndrome in 10 single neuropathy or multiple weeks Surrounding nerve 5 (2) basic skills required: name cases (?) standard full neurological physical examinations and locate 60 waist size 10 reading 20 EMG-EEG reading 20 skull and spinal CT reading 80 head and spine MRI reading 80 Department of Neurology ... (2) clinical knowledge and high skills: basic standards on the basis of further a high standard of inflammatory and degenerative diseases of the nervous system in pathogenesis, clinical presentation, diagnosis, differential diagnosis and therapeutic principle. Familiar with common neurological diseases such as encephalitis, epilepsy, EEG; grasp the imaging of inflammation and degeneration of the nervous system, as well as the results of Transcranial Doppler examination of clinical significance. (3) foreign language, teaching, research and other requirements: can read professional foreign language documents and perform simple medical English