Cause analysis of network packet loss 1. Problems with the network itself
The problems of the network itself can be divided into the following categories: network failures beyond its jurisdiction and ISP network problems.
Second, physical line failure.
Turn on and off when the WAN line is found. This may be the fault of the line or the fault of the user. In order to distinguish whether it is a line fault, you can do the following tests. If the WAN line is realized through a router, you can log in to the router and send a large number of packets to the WAN interface of the opposite router through extended ping for testing. If the line is realized through a three-layer switch, you can connect a computer at both ends of the line and set the IP address as the WAN interface address of the local three-layer routing switch. Ping peer computer address? The command to test. If there is no packet loss in the above test, it means that the line provided by the line operator is good, and the fault is caused by the user himself, which needs further search. If packet loss occurs in the above test, it means that the fault is caused by the line provided by the line supplier, and it is necessary to contact the line supplier to solve the problem as soon as possible. There are many packet loss phenomena caused by physical lines, such as optical fiber connection problems, misalignment between jumpers and equipment interfaces, twisted pair, RJ-45 connectors and so on. In addition, datagram errors caused by random noise or sudden noise, interference of radio frequency signals and signal attenuation may all cause packet loss. Network tester can be used to check the quality of lines.
Third, network equipment failures and network bottlenecks.
Equipment failure mainly refers to the failure of equipment hardware, excluding packet loss caused by improper software configuration. If the network card is broken, one port of the switch has a physical failure, the electrical port of the optical fiber transceiver does not match the interface of the network device, or the interface duplex mode of the devices at both ends does not match.
There are many reasons for the increase of packet loss rate caused by network congestion, mainly occupying a lot of router resources. If the switch performs CRC error detection and length check on all received packets, it will discard the packets with errors and forward the correct packets. However, in this process, some packets with errors were not detected in CRC error detection and length check. Such packets will not be sent out or discarded in the forwarding process, but will be accumulated in the dynamic cache and will never be sent out. When the cache is full, it will cause the switch to crash. Therefore, the packet cannot reach the destination host.
Network bottleneck refers to some related factors that affect network transmission performance and stability, such as network topology, network cable, network card, server configuration, network connection equipment, etc.
Fourth, cyber attacks.
In fact, cyber attacks are very common and inevitable. No matter what kind of attacks, such as worms, Trojan attacks and DOS attacks, these attacks with certain characteristic libraries can easily escape the detection of firewalls or IDS and enter the intranet, resulting in network paralysis, packet loss and even disconnection. In case of network packet loss, how to analyze whether it is caused by network attack? Here, with the help of network analysis tools, through the collection and analysis of all communication packets in the network, we can detect the faults caused by such attacks.
Verb (abbreviation for verb) network loop
Network loops are usually caused by wrong network wiring or network configuration. If there is a loop in the network, there may be a broadcast storm, which will lead to network packet loss, delay and other failures. In the analysis of this kind of fault by network analysis tools, we can mainly start from the following aspects: check whether there is an ICMP network redirection event in the diagnosis view, and check some key parameters such as IP identifier and TTL of each IP packet through packet decoding. If the loop fault detection is caused by a network configuration error, such as a routing table setting error, refer to the relevant manual. Secondly, if the loop is caused by network wiring, then in the packet decoding view, we can analyze and compare the IP identifier and TTL of the packet.
Sixth, the broadcast storm.
Broadcast storm detection is relatively simple. Through the summary statistics view of Kelai network analysis system, we can see the network broadcast traffic, broadcast data packets and other information. Usually, if the broadcast traffic accounts for a large proportion, it will definitely affect the normal network communication and cause network congestion, which will lead to network delay, packet loss and other problems.
Seven, the network traffic takes up a lot.
The occupation of network traffic is usually one of the important reasons leading to network packet loss. In particular, the traffic generated by P2P download has a great influence on the network. According to authoritative survey, 70% of the traffic on the Internet is generated by P2P downloading. Therefore, the monitoring of traffic can be said to be a basic work in network management. Although many products can monitor traffic now, it is not very comprehensive. Through network analysis tools, various traffic types can be detected, such as total network traffic, broadcast/multicast traffic, traffic of a single VLAN, traffic of a single IP or MAC, etc. In addition, it can also display the traffic occupation of each business application in the network in detail. Therefore, in case of network packet loss, we can first check the problem of traffic occupation to see if the network bandwidth is insufficient due to some abnormal traffic occupation, which leads to the failure.
To sum up,? Network packet loss? It may be caused by various situations. Through the above analysis, I believe everyone is right? Network packet loss? There is a concept, and there are reasons? Network packet loss? The reasons are also understood to some extent. So, I believe everyone has seen it? Network packet loss? In this case, you should know how to solve it. Also, when people talk to you? Packet loss? Then you won't feel that you have lost some kind of bag. You can also treat friends who don't know the situation when necessary? Sweep literacy? Let them also increase their knowledge!
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