The hottest lanmeter network tester, the baby of n

Lanmeter network tester: take good care of the baby

fluke company is the authority of network maintenance in the world. The network detection tools produced by fluke company believe that every network manager has been in contact. This paper introduces how to find network faults through the lanmeter network tester of fluke company

there are often some thorny problems in management, such as slow network or poor performance. At this time, if there is a network tester to help detect faults, it will undoubtedly greatly improve work efficiency. The following describes how to use the lanmeter network tester of fluke company to detect slow network speed or poor performance from two aspects of hardware and software

I. diagnosis of hardware problems

run network stats test to check high network utilization and abnormal high collision rate. Apply a small amount of background traffic (LLC traffic of 100 frames per second, 100 bytes per frame) and run the test again. If you find that collisions or FCS errors increase as transmission increases, you should run cable scan

if the number of collisions is very high (more than 5%), run collision analysis tests to determine how much bandwidth is lost due to collisions. After adding the bandwidth loss caused by local and remote collisions, fault diagnosis is required if the average loss is greater than 0.5%. At the same time, check whether the collision is "sudden", and the increase of sudden collision does not increase with the increase of network flow. In other words, if the number of collisions changes greatly without corresponding to a large increase in traffic, there may be a serious physical layer problem somewhere. There must be some relationship between flow level and collision. If the network performance is at an acceptable level and the number of collisions is always large, there may be too many stations transmitting in the collision domain, or the network structure needs to be optimized to reduce the distance between network stations. Excessive collisions are often caused by physical media, such as missing or incorrect termination, discontinuous impedance (bad connectors, connecting cables, extruded cables, etc.), or bad cards

if the utilization rate is very high (the continuous peak is more than 60%) and the number of collisions is acceptable (the average value is less than 5%), then the network may be saturated. This is somewhat impossible, because if the Ethernet segment has a high utilization rate, it usually has a high collision rate. When the utilization is close to 100%, the number of collisions will far exceed the number of good frames. At this time, it may be necessary to install switches, bridges or routers to separate the network into small enough sub networks to support the traffic load

run the network stats test and check for errors (other than collisions). If there is an error, run the error stats test and use zoom to understand the MAC address of the problematic site, and then use expert-t to isolate the specific problem or use cable scan to check the cable. If the problem is intermittent, try to replace the suspected card, because these problems may not show up during the test

check whether the server or service the user is connecting to is at the far end of the WAN or connected through routing. If so, then using Ping test (Netware Ping, ICMP Ping) materials becomes a fundamental problem. The chemical industry is expected to check the response of the passing section and compare the results with your benchmark or hearing test results. In order to ensure that the frame is not lost, try to Ping continuously, and check that the number of requests is equal to the number of responses (IP hosts often fail to respond to the first Ping, so you need to try several times). If the number is inconsistent, the remote media or interconnection devices (bridges, routers, etc.) may be full or have problems. Frame loss is also a symptom of cable failure, such as the series winding of UTP cable or the earth loop of coaxial line. If you suspect that there is a frame loss, you can run a cable scan to test the cable connecting the slow site (and the corresponding file server) to the network, or connect any bridge or router and the cable between them

II. Diagnosis of software problems

run network stats test. If there is high network utilization, low collision, and few of them have independently developed the third component modulation technology and multi-level precipitation control technology, he is wrong, you can run the top sender test to know which site has the greatest impact on traffic. You should go to the site to check and see what users are doing on the network. You may also need to ask what you are doing during the off peak period, or you may need to regularly check and revise the experimental machine and move the user to another segment to improve the service of the network to other users

if the utilization, collision and error are low, ask the user about the application and server they are using. Check the corresponding servers to see if they are in a high utilization state (which is different from network utilization). Set the top sender filter address for the network monitor to find out which sites request the most services. The test of top sender can also set address filtering for users who are feeling poor network performance in order to find out which server they are connecting to. Users should also be asked about their requirements for servers or services

run protocol mix to know which protocols occupy most of the bandwidth. Like the network monitor, set the upper layer top sender filter (such as Netware, tcp/ip, NetBIOS, banyan, etc.). This top sender test can understand which site is most dependent on a particular network resource. Then check to see if the work can be moved to a less used server or shared by several servers

when the network failure is related to the utilization rate - the collision is very low and there are no errors, which may be related to the application software and file server. For example, the cache set by the server may be too small; Too little cache is reserved; Insufficient ram in the server; The hard disk space of the server is too small; 8-bit card is used. At the same time, the software program may be running disk requests that cause an abnormal number. It may be necessary to move the application to another server, or upgrade the existing server or add a new server

run the network stats test and check for errors (other than collisions). If there is an error, run the error stats test and use zoom to understand the MAC address of the problematic site heggs, and then use expert-t to isolate the specific problem or use cable scan to check the cable. If the problem is intermittent, try to replace the suspected card, because these problems may not show up during the test

check whether the server or service the user is connecting to is at the far end of the WAN or connected through routing. If so, use Ping test (Netware Ping, ICMP Ping) to check the response of the passing segment, and compare the results with your benchmark or hearing test results. In order to ensure that the frame is not lost, try to Ping continuously, and check that the number of requests is equal to the number of responses (IP hosts often fail to respond to the first Ping, so you need to try several times). If the number is inconsistent, the remote media or interconnection devices (bridges, routers, etc.) may be full or have problems. Frame loss is also a symptom of cable failure, such as the series winding of UTP cable or the earth loop of coaxial line. If you suspect that there is a frame loss, you can run a cable scan to test the cable connecting the slow site (and the corresponding file server) to the network, or connect any bridge or router and the cable between them. (end)