Advanced Linux Routing and Traffic Control: Queue rules for bandwidth management

Now, when I figure it out, I'm really surprised. Linux 2.2/2.4 can manage bandwidth as well as the highest-end dedicated bandwidth management systems. Even better than frame Relay and ATM.

To avoid conceptual confusion, TC uses the following rules to describe bandwidth:

mbps = http://www.aliyun.com/zixun/aggregation/12560.html ">1024 kbps = 1024 * 1024 bps => byte/s
Mbit = 1024 kbit => kilo s.
MB = 1024 KB = 1024 * 1024 b => byte
Mbit = 1024 kbit => kilo bit.

Default: Numbers are stored in bps and B.
However, when the TC output rate is used, it is shown as follows:

1Mbit = 1024 kbit = 1024 * 1024 bps => byte/s

1. Interpretation of queues and queue requirements

Using queues, we determine how data is sent. It must be realized that we can only reshape the data to be sent.

Depending on how the Internet works, we can't directly control what data people send us. It's kind of like our home letter box, you can't control the world, contact everyone, and modify the number of emails you send to others.

However, the Internet relies heavily on TCP/IP, and some of its features are useful. Because TCP/IP has no way of knowing the network capacity between the two hosts, it tries to send data more and more quickly (so-called "slow technology"), slowing down when data is lost due to insufficient network capacity. The actual situation is smarter than this method and we'll discuss it later.

It's like when you're not finished reading half the mail, you want someone to stop sending you a letter. Unlike in the real world, this can be done on the Internet. (This example is not appropriate, the TCP/IP mechanism is not implemented at the network layer, but rather depends on the TCP protocol of the Transport Layer)

If you have a router and want to be able to prevent some hosts from downloading too quickly, you need to perform traffic shaping on your router's internal network card-the NIC that sends the packet to your intranet host.

You also have to make sure that you are controlling the bottleneck. If you have a 100M Ethernet card, and your router has a link speed of 256k, you must ensure that the amount of data you send does not exceed the processing capacity of the router. Otherwise, the router is controlling the link and shaping the bandwidth, not you. It can be said that the queues we need to have must be the slowest link in a series of links. Luckily, it's easy.