operation of ping - (computer networking)
TRANSCRIPT
Operation of Ping
Presented by:Jubayer Al Mahmud
Table of Contents What is ping? Origin of the name How ping works? Successful ping test Unsuccessful ping test Error indications Packet Loss Packet Latency Traceroute vs Ping Ping in Online Video Games What affects ping? Benefits Drawbacks Ping of Death
What is Ping?
A computer network utility to determine whether a specific IP address is accessible
Measures the round-trip time for messages sent from the originating host to a destination computer and back
Origin of the name
PING: Packet Internet Groper
Originated from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects underwater
Written by Mike Muuss in December, 1983
How ping works?
Operates by sending ICMP echo request (ping) packets to the target host and waiting for an ICMP echo reply (pong)
It measures the round-trip time from transmission to reception, reporting errors and packet loss
Successful Ping test
Shows a statistical summary of the response packets received
Also includes minimum, maximum and mean RTT
Successful Ping test
Successful Ping test
No guarantee!!!
The real request might not pass through
Unsuccessful Ping test
In cases of no response from the target host, most implementations of ping print notifications about timing out periodically
In case of specific problem, ping notification includes error notification indicating that problem
Unsuccessful Ping test
Unsuccessful Ping test
No guarantee!!!
The real request might pass through
Error indications
H, !N or !P – host, network or protocol unreachable S – source route failed F – fragmentation needed U or !W – destination network/host unknown I – source host is isolated A – communication with destination network
administratively prohibited
Error indications
Z – communication with destination host administratively prohibited
Q – for this ToS the destination network is unreachable
T – for this ToS the destination host is unreachable X – communication administratively prohibited V – host precedence violation C – precedence cutoff in effect
Packet Loss Packet loss occurs when one or more packets of data
travelling across a computer network fail to reach their destination
Packet loss can be caused by a number of factors:• Signal degradation over the network medium due to multi-
path fading• Packet drop because of channel congestion• corrupted packets rejected in-transit• faulty networking hardware
Packet Latency Contributes to network speed Refers to any of several kinds of delays typically
incurred in processing of network data It is the Round Trip Time showed in Ping operation Measured in milliseconds (ms) On DSL or cable Internet connections, latencies of less
than 100 ms are typical and less than 25 ms desired. Satellite Internet connections have average 500 ms or
higher latency.
Traceroute vs Ping
Traceroute is a utility that traces a packet from a computer to an Internet host
It shows how many hops the packet requires to reach the host and how long each hop takes
Traceroute vs Ping
Ping will determine the reachability of a host on an IP network
Ping will also test the speed of a connection to the server
Traceroute determines how long a packet (32 bytes in size) takes to go from a computer to the host and back to the computer again
Ping in Online Video Games
Network latency between a player’s computer (client) and either the game server or another client
Instead of using traditional ICMP packets, programmers often build their own latency detection into existing game packets
Low ping provides smoother gameplay by allowing faster updates of game data.
What affects ping ? Depends on distance and internet traffic at that time
Connection may have to be routed through 15 or 20 hops (different locations) to reach the destination server
Try to chose a closer server for lower latency
What affects ping ? Congested/overloaded routers on the way to the
target machine
Excessive network utilization (downloading) can result in increased latency due to the fact that the packets experience queuing delay
To ensure low latency, all other unnecessary network usage should be halted
Benefits
Determines the status of the network
Troubleshoots networks
Determines response time of a destined IP address
Determines network latency
Drawbacks
Adds load to the system, causing problem with routers across the internet
Ping Flood (DoS attack), victim is overwhelmed with ICMP echo requests.
Ping of death
Ping of Death A type of Denial of Service (DoS) attack
Such an attack in 1996 involved sending IP packets of a size greater than 65,535 bytes to the target computer
IP packets of this size are illegal, but applications can be built that are capable of creating them
Operating systems not programmed to handle such a situation froze, crashed or rebooted
Ping of Death By the end of 1997, operating system vendors had
made patches available to avoid the ping of death
Thank You