What is ping in SEO

Ping terminology and definition

The ICMP (Internet Control Message Protocol) is used to exchange information in computer networks. The basis for the network is the Internet protocol version IPv4. The new version of the protocol is IPv6, which is compatible with the ICMPv6. The new version of the ICMP protocol became necessary because of the prefix length of the IPv6. The ICMP can be found in the OSI model in the transport layer. The IP protocol is assigned to the network layer below. Based on this assignment, ICMP checks every data packet for errors. An answer is only given to a unique IP address. If a host (computer, router, switch, etc.) is not active, no unique IP address can be determined. ICMP will not be able to send a message from the host. In 1983 Mike Muus wrote the ping program for 4.2a BSD UNIX to measure loading times with time-controlled ICMP echoes.

How the PING program works

When a host is checked for availability, the administrator sends an ICMP packet with the type 0x08 to the corresponding host. The recipient replies with a data packet ICMP type 0x00 (Pong). Only one host that uses the same communication protocol can be checked. The protocol (language) is independent of the physical structure of the network. It is not relevant for the ICMP whether Ethernet is connected to Token Ring via different buildings or other locations. The operating system (Windows, Novell, Unix) is only important for the ICMP insofar as the TCP / IP protocol stack is installed and loaded. If the target computer cannot be reached, the message "Network unreachable" will appear. This message indicates that the target computer is on a different network and the message was sent by a router. It is possible that some hosts are configured in such a way that they do not send an echo to an ICMP request. The reason can be a gateway that implements a secure VPN line to some computers and treats it separately. The administrator enters the console command "PING IP address" to check and receives a response from the host with the destination address. This ensures that the computer is connected to the network.
The syntax for input can be specified by the admin as FQDN (Fully Qualified Domain Name), which makes it unnecessary to specify the IP address. The specification is referred to as an absolute name and is based on the hierarchy of the domain in the Internet. An example is “.Personalwesen.Bebeispiel.com“. A DNS server resolves the absolute name and assigns it to the correct IP address in conjunction with a DHCP server. The prerequisite for this information is that the "Send ICMP packet" option is activated on the DNS server. A comparison in the host files using a broadcast is only possible with IPv4. With IPv6, most routers are able to send a fill packet to compare their host tables. These link local addresses are used for addressing in closed networks. The routers can determine the necessary configuration using SLAAC. The filtering of ICMPv6 packets is prevented by the NDP (Neighbor Discovery Protocol). Multicast is used to automatically assign addresses using ICMPv6 packets.

The duration of a PING

The time from a transmitter to a receiver is measured in bit times in a computer network. It corresponds to the time in which a bit can be sent from one host to another. A bit interval indicates the time between two bits. The bit interval and the technology for transmitting the data packets are decisive for the bit transmission time. Ethernet is the most commonly used technology to transfer data. If a PING is sent, it must be ensured that there is no collision on the data line. The CSMA / CD technology was developed for this purpose. This technology first checks whether the line is free. If the medium is free, the PING is sent and the line continues to be monitored at the same time. If a collision occurs, a jam signal is sent to all routers. The jam ensures that the fault is known to all routers and transceivers. In the event that the line is busy, an attempt is made to repeat the transmission until the maximum number of repetitions is reached. If the number of transmission attempts is exceeded, an error message is also sent. Only now is the line tapped again to see whether it is free. A wireless LAN uses the same technology called CSMA / CA.
The RTT (Round Trip Time) is used in TCP / IP networks when packets are to be resent after no acknowledgment has been received. In large networks, the transport capacity must be adapted to the protocol behavior. To do this, RTT measures the time difference between the sending and the arrival of the packets. This process is repeated and the averaged value forms the basis. If packets are sent several times due to a collision, this value is not included in the RTT. The round trip time is a good combination with the PING in a large TCP / IP network. The ICMP protocol, which forwards the information from the PING, is routed differently than the RTT. Intelligent (self-learning) routers form a good control in connection with the ICMPv6 and the PING. The packet loss rates in connection with the sequence numbers and the packet sizes are important information for the admin when configuring the router. Packet sizes can be fragmented on the basis of this information, or a route for data transmission between affected hosts can be improved. This advantage of the ICMP is not given with the RTT. RTT can only determine the packet cycle time.

For your quotes: just copy and paste the permalink