What to do if a router loses a packet

One, memory fragmentation refers to the router memory is divided into many discontinuous blocks. He will result in lower memory utilization, which can cause memory errors and affect the performance of routers. It will also lead to the problem of router packet loss, in fact, not only the memory of the router fragmentation problem, the common hard disk also exists in this problem.

If the Microsoft operating system with a defragmentation tool, you can protect users to defragment the hard disk to improve the storage capacity of the hard disk and storage performance. This means that the memory fragment is actually similar to the hard disk fragmentation.

Second, how to determine the memory of the router is fragmented? Here is the main use of the psychic router with the show memory command. This command displays information about the current memory.

If this command is executed, the current available memory (free) and the maximum available fast (largest) value are displayed, and the network administrator compares the two values to determine the impact of fragmentation on router performance. This is primarily to compare the available memory of the router with the maximum available fast size.

If the router's available memory is closer to the maximum available fast size, it means that although the router is fragmented, it has little impact. However, if the largest available block is small, such as only a few one-tenth of the maximum available memory, then the router memory fragmentation problem is more serious.

Three, such as the router's available memory is 20M, and the largest available block size of 15M, it means that the router memory is a certain fragment, but this fragment does not affect the normal operation of the router. If the available memory is 20M and the maximum usable block is 0.8M, there are more fragments in the router's memory.

There is not enough fast available in continuous continuous memory, which can cause serious memory allocation problems, such as the loss of packets that result in one or more interfaces being intermittent.

In the router memory, a certain amount of memory fragmentation is allowed. So far, no memory management technology has said that it can completely avoid the production of memory fragmentation. Just this fragment to ensure a reasonable value.

Iv. in fact, the relationship between this usable block and the available memory we can use the drawer in the cupboard to express. such as a cabinet usable capacity is larger, but it divides the size of more than 1000 lattice. The space capacity of each lattice is limited.

When large data needs to be stored, the whole capacity is sufficient, but the capacity of the small lattice is not enough. At this point, there will be a problem of packet loss.

It appears that memory is sufficient at this time, but there is no contiguous space in memory to store the data at this time. So these seemingly large available memory, in fact, can not save much data.

If you determine that there is not too much fragmentation in the router's memory, the network administrator will consider whether the packet is lost due to CPU overload. To see the CPU usage, you can use the show process command to view the CPU usage of the router, which shows the CPU usage of the router's CPU for the last 5 seconds, the last 1 minutes, and the last 5 minutes.

Because CPU usage has been changing, the main relationship between network administrators is the average CPU usage within 5 minutes. At this point, it can be explained that the Router interface packet loss is probably caused by CPU overload.

If you are sure that the router is overloaded, then the network administrator needs to be sure which process is consuming a lot of memory. Only to find out the culprit, the network administrator can prescribe the right remedy, solve the problem.

If the network administrator through the query found that the SRB background process occupies a large number of CPUs, it shows that the Network Bridge storm. To solve the problem of CPU overload, to achieve this goal, network administrators can query the router's memory allocation information through the show PROCESS Memory command.

By executing this command, the system will feed back the current amount of memory available to the router, using the amount of information. Also reflects the amount of memory space that each process occupies. This process is problematic if the memory consumed by a process is larger than the CPU that is shown above. The network administrator will be able to troubleshoot these available processes individually.

Seven, such as sometimes the network administrator can force some CPU-intensive processes to shut down, and then test whether the message loss has improved. If there is a noticeable improvement, then the cause of the problem is found.

At this point the network administrator can prescribe the right remedy, analysis of the process in the end of the corresponding service is what, why occupy so much CPU resources and memory resources.

If you can, you can turn off the service to reduce packet loss and ensure the normal operation of other services. Wait until you have identified the cause of the problem, fix it, and then restart it.

After reading the above, understand the reasons for packet loss, as long as the targeted measures can solve the problem, pay attention to the router using a lot of exchange technology, they are dependent on the message. If the message is lost, then the advanced Exchange technology will not work, how to prevent the loss of the message is critical.