TTL meaning detailed

Friends of the website know that ping commands are very useful. What does the TTL mean? Such a problem, in fact, the TTL is more about the network, such as we ping IP or ping the site can see the TTL value , the following figure, I believe that the user asked the question should be ping in the TTL what meaning it, Let's take a detailed description of what the TTL means. Hope to help you!

In the network is mainly refers to ping speed in the TTL value, ping command believe that familiar with the network of friends are not unfamiliar, but also for you to introduce a lot of ping command related knowledge, in the network application, ping speed and IP address are very commonly used commands, through ping IP or Web site can know whether the network unblocked or network transmission quality, etc., is the network of technical personnel commonly used to detect network commands. The following figure is a screenshot of Ping's network speed:

　　What does it mean to ping the TTL in network speed?

You can see from the picture above, Ping computer Pepsi net speed in the ttl=114, then this TTL value is what mean? In layman's terms, the TTL is a value in the IP protocol packet that tells the network whether the packet is too long on the network and should be discarded. There are a number of reasons why the package cannot be delivered to the destination for a certain amount of time. The solution is to discard the packet after a period of time and then send a message to the sender, who will decide whether to resend it. The initial value of the TTL is usually the system default, which is a 8-bit field in the header. The first idea of the TTL is to determine a time range that discards the package over that time. Because each router has at least one less TTL domain, the TTL usually represents the maximum number of routers that the packet can pass before being discarded. When the count to 0 o'clock, the router decides to discard the packet and send an ICMP message to the original sender.

In a nutshell, the TTL is a time value, and the TTL is the time to send the message back. is a life cycle, he can not compute routing, he has nothing to do with the routing, and the server operating system, by observing the size of the TTL value, you can roughly determine the target host system type, in general:

The TTL value is between 100 and 130, and the host system is windows

The TTL value is between 240 and 255, and the host system is UNIX or Linux

So we will find that ping different Web sites or different server host to get the TTL value is not the same, mainly by the server host operating system decisions, generally we simply understand this knowledge can be said to understand the basic meaning of the TTL.

TTL other meaning aspect, in the circuit has the TTL level, the TTL level signal is utilized most because the usual data expression uses the binary stipulation, +5v is equivalent to the logic "1", the 0V is equivalent to the logical "0", this is called the TTL (transistor-transistor logic level) signaling system, This is the standard technique for communication between parts of a device controlled by a computer processor. In life, the TTL is also referred to: Lesbian, T sense for the husband, P is the wife of care, TTL refers to TT love, that is, two t together, T is generally a very similar to the girls who look like boys.

What does the TTL mean? Here is a more comprehensive summary for everyone, in fact, more times we refer to ping speed in the TTL value, read this article I believe that we have a more clear TTL.

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