ping (privileged)

To diagnose basic network connectivity on Apollo, AppleTalk, Connectionless Network Service (CLNS), DECnet, IP, Novell IPX, VINES, or XNS networks, use the ping (packet internet groper) privileged EXEC command.

ping [protocol] {host | address}

Syntax Description

protocol

(Optional) Protocol keyword, one of apollo, appletalk, clns, decnet, ip, ipx, vines, or xns.

host

Host name of system to ping.

address

Address of system to ping.

Command Modes

Privileged EXEC

Command History
Release Modification

10.0

This command was introduced.

Usage Guidelines

The ping program sends an echo request packet to an address, then awaits a reply. Ping output can help you evaluate path-to-host reliability, delays over the path, and whether the host can be reached or is functioning.

To abnormally terminate a ping session, type the escape sequence---by default, Ctrl-^ X. You type the default by simultaneously pressing and releasing the Ctrl, Shift, and 6 keys, and then pressing the X key.

The table below describes the test characters that the ping facility sends.


Table 67: ping Test Characters
Character Description

!

Each exclamation point indicates receipt of a reply.

.

Each period indicates the network server timed out while waiting for a reply.

U

A destination unreachable error PDU was received.

C

A congestion experienced packet was received.

I

User interrupted test.

?

Unknown packet type.

&

Packet lifetime exceeded.

  Note Not all protocols require hosts to support pings. For some protocols, the pings are Cisco-defined and are only answered by another Cisco router.

Examples

After you enter the ping command in privileged mode, the system prompts for one of the following keywords: appletalk, clns, ip, novell, apollo, vines, decnet, or xns. The default protocol is IP.

If you enter a host name or address on the same line as the ping command, the default action is taken as appropriate for the protocol type of that name or address.

Although the precise dialog varies somewhat from protocol to protocol, all are similar to the ping session using default values shown in the following output: 

Router# ping
Protocol [ip]:
Target IP address: 192.168.7.27
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.7.27, timeout is 2 seconds:
!!!!!
Success rate is 100 percent, round-trip min/avg/max = 1/2/4 ms

The table below describes the default ping fields shown in the display.


Table 68: ping Field Descriptions
Field Description

Protocol [ip]:

Prompts for a supported protocol. Enter appletalk, clns, ip, novell, apollo, vines, decnet, or xns. Default: ip.

Target IP address:

Prompts for the IP address or host name of the destination node you plan to ping. If you have specified a supported protocol other than IP, enter an appropriate address for that protocol here. Default: none.

Repeat count [5]:

Number of ping packets that will be sent to the destination address. Default: 5.

Datagram size [100]:

Size of the ping packet (in bytes). Default: 100 bytes.

Timeout in seconds [2]:

Timeout interval. Default: 2 (seconds).

Extended commands [n]:

Specifies whether or not a series of additional commands appears. Many of the following displays and tables show and describe these commands.

Sweep range of sizes [n]:

Allows you to vary the sizes of the echo packets being sent. This capability is useful for determining the minimum sizes of the MTUs configured on the nodes along the path to the destination address. Packet fragmentation contributing to performance problems can then be reduced.

!!!!!

Each exclamation point (!) indicates receipt of a reply. A period (.) indicates the network server timed out while waiting for a reply. Other characters may appear in the ping output display, depending on the protocol type.

Success rate is 100 percent

Percentage of packets successfully echoed back to the router. Anything less than 80 percent is usually considered problematic.

round-trip min/avg/max = 1/2/4 ms

Round-trip travel time intervals for the protocol echo packets, including minimum/average/maximum (in milliseconds).

Related Commands
Command Description

ping (user)

Sends ISO CLNS echo packets to test the reachability of a remote router over a connectionless OSI network.