Utility Ping: How dose PING work?
A Ping utility is essentially a system administrator's tool that is used to see if a computer is operating and also to see if network connections are intact.
Ping uses the Internet Control Message Protocol (ICMP) Echo function which is detailed in RFC 792. A small packet of information containing an ICMP ECHO_REQUEST is sent through the network to either a particular IP address or a domain name. This packet contains 64 bytes - 56 data bytes and 8 bytes of protocol reader information.
The computer that sent the packet then waits (or 'listens') for a ECHO_REPLY packet from the specified IP address. The ping program then evaluates this reply, and a report is shown. You can check several things with the ping program: can you reach another computer, how long does it take to bounce a packet off of another site. The time taken to Send and Receive a Data Packet is calculated in Milliseconds.
This helps us to know the speed of the connection. If the connections are good and the target computer is up, a good return packet will be received. If a computer does not return a ping, it does not necessarily indicate a problem. Not every computer will ping you back. Most do, however, and if you have successfully pinged a computer in the past, but you cannot get a ping back today, there is a problem in the network (less common) or with the computer (most likely.) If it takes a long time for a ping to return, it is an indication that the network (most commonly) or the computer (less likely) is extremely busy. Additionally, an administrator can use Ping to test out name resolution. If the packet bounces back when sent to the IP address but not when sent to the name, then the system is having a problem matching the name to the IP address.
As mentioned previously, Ping has also evoloved from a noun/acronym into a verb, for example: "Ping server X to see if it is up" The time it takes for the packet to get to the target computer and back again is known as the round trip time. If this takes an extended period of time, it is indicative that something may be wrong. |
