Game similar to lawn tennis that is played on a tabletop with wooden paddles and a small, hollow, plastic ball. The object is to hit the ball so that it goes over the net and bounces on the opponent's half of the table in such a way as to defeat the opponent's attempt to reach and return it. Both singles and doubles games are played. A match consists of the best of any odd number of games, each game being won by the player or team who first reaches 11 points or who, after 10 points each, gains a two-point lead. Invented in England in the early 20th century, it soon spread throughout the world. Since the mid-1950s, East Asian countries have dominated the sport. It has been an Olympic sport for both men and women since 1988.
Learn more about table tennis with a free trial on Britannica.com.
The word ping is also frequently used as a verb or noun, where it can refer directly to the round-trip time, the act of running a ping program or measuring the round-trip time.
Mike Muuss wrote the program in December, 1983, as a tool to troubleshoot odd behavior on an IP network. He named it after the pulses of sound made by a sonar, since its operation is analogous to active sonar in submarines, in which an operator issues a pulse of energy at the target, which then bounces from the target and is received by the operator. (The pulse of energy in sonar is analogous to a network packet in ping.) Later David L. Mills provided a backronym, "Packet InterNet Groper" (sometimes also defined as "Packet Inter-Network Groper").
The usefulness of ping in assisting the "diagnosis" of Internet connectivity issues was impaired from late in 2003, when a number of Internet Service Providers began filtering out ICMP Type 8 (echo request) messages at their network boundaries.
This was partly due to the increasing use of ping for target reconnaissance, for example by Internet worms such as Welchia that flood the Internet with ping requests in order to locate new hosts to infect. Not only did the availability of ping responses leak information to an attacker, it added to the overall load on networks, causing problems for routers across the Internet.
Although RFC 1122 prescribes that any host must accept an echo-request and issue an echo-reply in return, one finds that this standard is frequently not followed on the public Internet. Notably, Windows XP SP2 will not respond to an echo request on the public Internet in the default configuration. (See Troubleshooting Windows Firewall in Microsoft Windows XP Service Pack 2
|Bit 0 - 7||Bit 8 - 15||Bit 16 - 23||Bit 24 - 31|
| IP Header|
(160 bits OR 20 Bytes)
|Version/IHL||Type of service||Length|
|Identification||flags et offset|
|Time To Live(TTL)||Protocol||Checksum|
|Source IP address|
|Destination IP address|
| ICMP Payload|
(64+ bits OR 8+ Bytes)
|Type of message||Code||Checksum|
Generic composition of an ICMP packet
admin@localhost# ping en.wikipedia.org
PING rr.pmtpa.wikimedia.org (184.108.40.206) 56(84) bytes of data.
64 bytes from rr.pmtpa.wikimedia.org (220.127.116.11): icmp_seq=1 ttl=52 time=87.7 ms
64 bytes from rr.pmtpa.wikimedia.org (18.104.22.168): icmp_seq=2 ttl=52 time=95.6 ms
64 bytes from rr.pmtpa.wikimedia.org (22.214.171.124): icmp_seq=3 ttl=52 time=85.4 ms
64 bytes from rr.pmtpa.wikimedia.org (126.96.36.199): icmp_seq=4 ttl=52 time=95.8 ms
64 bytes from rr.pmtpa.wikimedia.org (188.8.131.52): icmp_seq=5 ttl=52 time=87.0 ms
64 bytes from rr.pmtpa.wikimedia.org (184.108.40.206): icmp_seq=6 ttl=52 time=97.6 ms
--- rr.pmtpa.wikimedia.org ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 8998ms
rtt min/avg/max/mdev = 78.162/89.213/97.695/6.836 ms
This output shows that en.wikipedia.org is a DNS CNAME record for rr.pmtpa.wikimedia.org which then resolves to 220.127.116.11.
The output then shows the results of making 10 pings to 18.104.22.168 with the results summarized at the end. (To stop the program in Linux or Windows, press Ctrl+C.)
en.wikipedia.orgunder Windows (Vista used in the following example) from within the Command Prompt:
[localhost] ping en.wikipedia.org
Pinging rr.pmtpa.wikimedia.org [22.214.171.124] with 32 bytes of data:
Reply from 126.96.36.199: bytes=32 time=57ms TTL=44
Reply from 188.8.131.52: bytes=32 time=59ms TTL=44
Reply from 184.108.40.206: bytes=32 time=59ms TTL=44
Reply from 220.127.116.11: bytes=32 time=54ms TTL=44
Ping statistics for 18.104.22.168:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 54ms, Maximum = 59ms, Average = 57ms
Macintosh:~ user$ ping -c 10 en.wikipedia.org PING rr.knams.wikimedia.org (22.214.171.124): 56 data bytes 64 bytes from 126.96.36.199: icmp_seq=0 ttl=53 time=40.019 ms 64 bytes from 188.8.131.52: icmp_seq=1 ttl=53 time=47.502 ms 64 bytes from 184.108.40.206: icmp_seq=2 ttl=53 time=43.208 ms 64 bytes from 220.127.116.11: icmp_seq=3 ttl=53 time=50.851 ms 64 bytes from 18.104.22.168: icmp_seq=4 ttl=53 time=46.556 ms 64 bytes from 22.214.171.124: icmp_seq=5 ttl=53 time=42.180 ms 64 bytes from 126.96.36.199: icmp_seq=6 ttl=53 time=49.853 ms 64 bytes from 188.8.131.52: icmp_seq=7 ttl=53 time=45.556 ms 64 bytes from 184.108.40.206: icmp_seq=8 ttl=53 time=41.186 ms 64 bytes from 220.127.116.11: icmp_seq=9 ttl=53 time=48.836 ms
--- rr.knams.wikimedia.org ping statistics --- 10 packets transmitted, 10 packets received, 0% packet loss round-trip min/avg/max/stddev = 40.019/45.575/50.851/3.588 ms
|Type = 8||Code = 0||Header Checksum|
|Type = 0||Code = 0||Header Checksum|
The payload of the packet is generally filled with letters of the alphabet as this ASCII tcpdump shows
16:24:47.966461 IP (tos 0x0, ttl 128, id 15103, offset 0, flags [none], proto: ICMP (1), length: 60) 192.168.146.22 > 192.168.144.5: ICMP echo request, id 1, seq 38, length 40
0x0000: 4500 003c 3aff 0000 8001 5c55 c0a8 9216 E..<:.....U....
0x0010: c0a8 9005 0800 4d35 0001 0026 6162 6364 ......M5...&abcd
0x0020: 6566 6768 696a 6b6c 6d6e 6f70 7172 7374 efghijklmnopqrst
0x0030: 7576 7761 6263 6465 6667 6869 uvwabcdefghi
In network multiplayer games like Unreal Tournament, Quake, Battlefield 2142, etc., the server notes the time it requires for a game packet to reach a client and a response to be received. This round-trip time is usually reported as the player's 'ping'. It is used as an effective measurement of the player's lag, with lower ping times being desirable. Note that this style of ping typically does not use ICMP packets.