NAME

linkloop − verify LAN connectivity with link-level loopback

SYNOPSIS

linkloop [−n count] [−f devfile] [−t timeout] [−s size] [−r rif] [−v] linkaddr1 [linkaddr2 ...]

DESCRIPTION

linkloop uses IEEE 802.2 link-level test frames to check connectivity within a local area network (LAN).  This program differs from the remote loopback capability of rlb (see rlb(1M)) in that it tests only link-level connectivity; not transport-level connectivity.

The required parameter is the hardware station address (linkaddr1, linkaddr2, ...) of a remote node. linkloop tests the connectivity of the local node and the remote node specified by the 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, but 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. 

Options

linkloop recognizes the following options:

−n count Sets 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. 

−t timeout Sets 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 for timeout is 2 seconds. 

−s size Sets the size 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. 

−v Sets 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. 

−f devfile Specifies which device file to use.  The device file must be an LAN device file.  If no device file is entered, linkloop uses /dev/lan (Series 300/400) as the default.  If /dev/lan is not present or is the wrong type of device file, linkloop uses /dev/ieee (Series 300/400) as the default.  If no device file is entered, linkloop uses /dev/lan0 (Series 700) as the default.  If /dev/lan0 is not present or is the wrong type of device file, linkloop uses /dev/ieee0 (Series 700) as the default. 

-r rif The rif is the routing information field used for token-ring networks.  This information allows a user to specify the particular bridge route over which the token ring packet should be delivered.  The rif value is given as an even number of hexadecimal bytes separated by colons, up to a maximum of 16 bytes. 

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
Incorrect hardware station address was entered on the command line.

address is not individual
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. 

DIAGNOSTICS

illegal count parameter
count is not a non-negative integer, or the number specified is too large for the local computer. 

illegal timeout parameter
timeout is not a non-negative integer, or the number specified multiplied by 1000 is too large for the local computer. 

illegal size parameter
Size specified is not in the range from 0 to the maximum link data size. Remember that the maximum link data size may vary in value between different LAN connection types. 

unable to use device file
Specified device file does not exist or is of the wrong type, or linkloop is already being executed by another user. 

unable to use default device file
Default device file does not exist or is of the wrong type, or linkloop is already being executed by another user. 

invalid rif parameter
Values in the rif parameter were invalid.

rif parameter too long
The number of bytes in the rif parameter exceeded the maximum allowed (16).

rif parameter length must be even
The number of bytes in the rif parameter was odd. The number of bytes must be even.

AUTHOR

linkloop was developed by HP. 

FILES

/dev/lan first default device file for Series 300/400

/dev/ieee second default device file for Series 300/400

/dev/lan0 first default device file for Series 700

/dev/ieee0 second default device file for Series 700

SEE ALSO

lanscan(1M), lan(7). 

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992