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HP-UX 11i Version 3: February 2007

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linkloop — verify LAN connectivity with link-level loopback


linkloop [-i PPA] [-n count] [-r rif] [-s size] [-t timeout] [-v] linkaddr ...


The lanadmin, lanscan, and linkloop commands are deprecated. See WARNINGS for more information.


The linkloop command uses IEEE 802.2 link-level test frames to check connectivity within a local area network (LAN).

linkaddr is the hardware station address of a remote node. Several addresses can be specified at one time.

linkloop tests the connectivity of the local node and the remote node specified by each hardware station address. The hardware station address of a remote node can be found by executing lanscan on the remote node. This hardware station address is usually represented as a hexadecimal string prefixed with 0x. It can also be represented as a octal string prefixed with 0 or as a decimal string. The hardware station address must not be a multicast or broadcast address.


linkloop recognizes the following options:

-i PPA

Specify the PPA to use. If this option is omitted, linkloop uses the first PPA it encounters in an internal data structure.

-n count

Set the number of frames to transmit. If count is 0, linkloop transfers frames indefinitely until an interrupt signal (defined by the user shell) is received. The default value for count is 1.

-r rif

Specify the particular bridge route over which token ring packets should be delivered. rif is the routing information field used for token-ring networks. Its value is given as an even number of hexadecimal bytes separated by colons, up to a maximum of 16 bytes.

-s size

Set the size in bytes of the data message to send. The maximum data size is dependent on the type of LAN link being used. The default value is the maximum data byte count that can be used for the particular link.

-t timeout

Set the amount of time in seconds to wait for a reply from the remote node before aborting. If timeout is 0, linkloop waits indefinitely for a reply. The default value is 2 seconds.


Set the verbose option. In addition to the regular summary of test results, this option displays more extensive error information. If there are header or length errors, appropriate messages are displayed. All verbose output is preceded by the number of replies accepted before an error occurred.

Connectivity Test Results

linkloop aborts upon receipt of an interrupt signal. If aborted, the current results are printed.

linkloop prints the result of the link-level connectivity test. If the test fails, it prints a summary of the test and indicates the type of error. The possible messages are:

address has bad format

  • An incorrect hardware station address was entered on the command line.

address is not individual

  • The station address entered on the command line is either a multicast or broadcast address.

frames sent

  • Total number of frames sent.

frames received correctly

  • Total number of frames received without errors.

frames with length error

  • Received frame length does not match transmitted frame length. If the verbose option is set, the length received is printed.

frames with data error

  • Received frame does not match transmitted frame.

frames with header error

  • Number of frames received containing unexpected frame header information. Either the source address does not match the remote address, the destination address does not match the local address, or the control field is not the TEST frame control field. These frames are ignored. linkloop continues to try to receive the reply frame until the read operation times out.

reads that timed out

  • Count of how many read operations timed out before the reply was received.


illegal count parameter

  • The count specified in the -n option is a negative integer, or the number specified is too large for the local computer.

illegal timeout parameter

  • The timeout specified in the -t option is a negative integer, or the value specified multiplied by 1000 is too large for the local computer.

illegal size parameter

  • The size specified in the -s option is not in the range from 0 to the maximum link data size. Remember that the maximum link data size can vary in value for different LAN connection types. The current MTU can be obtained with the linkloop command.

No valid interface associated with PPA

  • The PPA specified in the -i option is not a valid PPA.

Unable to open device file /dev/dlpi

  • Device file /dev/dlpi does not exist.

invalid rif parameter

  • The rif value in the -r option is invalid.

rif parameter too long

  • The number of bytes in rif in the -r option exceeded 16, which is the maximum allowed.

rif parameter length must be even

  • The number of bytes in rif in the -r option is odd. The number of bytes must be even.


The lanadmin, lanscan, and linkloop commands are deprecated. These commands will be removed in a future HP-UX release. HP recommends the use of replacement command nwmgr(1M) to perform all network interface-related tasks.


linkloop was developed by HP.

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