A random second card that crosses the FireWire but the download speed is very fast.

[Problem]

A virtual disk of the old Internet cafe construction network master system of more than 100 machines. After the construction is completed, the attendance rate is not In the high case, the phenomenon of random second card crossing the fire line was found. When the remote location was found, the delay of all the large areas of the cf login interface was very high. At that time, the external network problem was suspected, but the download speed was found to be very fast, so there was not much doubt about the external network.

[Cause]

The user connects the network cables of the two core switches to the router, causing the client to communicate across the switch, because the router's switching performance is poor, resulting in router performance. When it falls, the above phenomenon appears.

As for why it is random, the reason is very simple. When the exchange data is low, the route can be processed, so no problem, but when the data exchange between the switches is relatively large, the router is too busy, directly affecting the network. The game has a high latency.

At the same time, some machines have been used. hdtune has a cache test with slow speed, only 4~5MB/S, and finally due to wiring problems.

The problematic topology is roughly as follows:

Normal topology:

[Solution]

Add backbone switching, connect sub-switches and all to The backbone core exchanges, so that the internal traffic of large traffic does not pass through the route, reducing the routing pressure and improving the transmission speed of the internal network.

[Question Analysis]

The value of sharing this case lies in some basic common sense. Some hard routes are 1, 2, 4 WAN ports, and then at least 4 LAN ports. In fact, the switching performance of this kind of route is very general, and it is incomparable with ordinary switches. If we connect two switches to any two LANs on this router, the route is too busy, so it will There is a problem, because the Internet cafe has 2 diskless servers, and the automatic balancing load is configured, so you will see random phenomenon, and the same client, it may be better after rebooting ……

When you are laying out the network, don't use the router as a switch. So deploy it, it's really not dead or hurt ……

Need to reflect on it, when others remotely help you solve the problem, if not Experience in this area, then only think that your internal network has problems, so it may lead to misjudgment, so some resources can not be saved, some uncertain factors, once the problem occurs, must be excluded first! In order to avoid problems Various Knot!