SMTPING(1M)SMTPING(1M)NAMEsmtping - send FDDI SMT Echo Request frames to FDDI stations
SYNOPSIS
/usr/etc/smtping [-dfnqv] [-c count] [-s size] [-l preload]
[-i interval] [-I interface] [-p pattern] host
DESCRIPTIONsmtping is a tool for FDDI ring testing, measurement and management. It
sends the FDDI Station Management (SMT) Echo request frames to elicit an
Echo response frame from other FDDI stations or concentrators. Echo
request frames (``pings'') have a MAC header, a SMT header, a transaction
ID and an INFO field. The INFO field has an 8-byte timestamp, and then
an arbitrary number of ``pad'' bytes used to fill out the packet. The
smtping tests for SMT connectivity; the related utility, ping(1M), tests
for the higher-level IP/ICMP connectivity.
The host can be a MAC address of a host or the symbolic name of its MAC
address which can be found in /etc/ethers or the NIS ethers.byname map.
The options are:
-c count
Stop after sending (and receiving) count Echo frames.
-d Set the SO_DEBUG option on the socket being used.
-f Flood ping. Outputs frames as fast as they come back or one hundred
times per second, whichever is more. For every Echo request frame
sent, a period '.' is printed, while for every Echo response
received a backspace is printed. This provides a rapid display of
how many packets are being dropped. Flooding can be extremely
stressful on a network and should be used with caution.
-i interval
Wait interval seconds between sending each frame. The default is to
wait for one second between each packet. This option is
incompatible with the -f option.
-l preload
Send preload frames as fast as possible before falling into the
normal mode of behavior.
-n Numeric output only. Does not try to translate the MAC address into
its symbolic name in the ethers database.
-p pattern
Specify up to 16 ``pad'' bytes to fill out the frames sent. This
option is useful for diagnosing data-dependent problems in a
network. For example, ``-p ff'' will cause the sent frames to be
filled with all 1s.
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SMTPING(1M)SMTPING(1M)-I interface
Use interface to send each ECHO frame and receive responses. The
interface is a string of the form ``name unit'', for example,
``ipg0''. The default is set to the station's primary interface.
-q Quiet output. Nothing is displayed except the summary line on
termination.
-s size
Send frames containing size bytes of data. The default is 12, which
translates into 64-byte SMT frame. The maximum allowed value is
65468 bytes(even though smtping accepts up to 65468 bytes of packet
size, any size larger than 4500 will result in failure because the
maximum FDDI packet size is 4500).
-v Verbose output. SMT frames other than Echo responses that are
received are listed.
smtping should be used primarily for manual fault isolation. Because of
the load it can impose on the network, it is unwise to use smtping during
normal operations or from automated scripts.
smtping continually sends one frame per second and prints one line of
output for every Echo response returned. If the -c count option is
given, only that number of requests is sent. No output is produced if
the station does not respond. Roundtrip times and frame loss statistics
are computed. If duplicate frames are received, they are not included in
the frame loss calculation, although the round trip time of these frames
is used in calculating the minimum/average/maximum round-trip time
numbers. When the specified number of frames have been sent (and
received) or if the program is terminated with an interrupt (SIGINT), a
brief summary is displayed. When not using the -f (flood) option, the
first interrupt, usually generated by control-C or DEL, causes smtping to
wait for its outstanding requests to return. It will wait no longer than
the longest round trip time encountered by previous, successful pings.
The second interrupt stops smtping immediately.
DUPLICATE AND DAMAGED PACKETSsmtping will report duplicate and damaged packets. Duplicate packets are
expected if the target address is a multicast or broadcast address;
otherwise duplicates are not expected.
Damaged packets are obviously serious cause for alarm and often indicate
broken hardware somewhere in the smtping packet's path (in the network or
in the hosts).
TRYING DIFFERENT DATA PATTERNS
The link-level layer should never treat packets differently depending on
the data contained in the data portion. Unfortunately, data-dependent
problems have been known to sneak into networks and remain undetected for
long periods of time. In many cases the particular pattern that will
have problems is something that doesn't have sufficient ``transitions'',
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SMTPING(1M)SMTPING(1M)
such as all 1s or all 0s, or a pattern right at the edge, such as almost
all 0s. It isn't necessarily enough to specify a data pattern of all 0s
(for example) on the command line because the pattern that is of interest
is at the data link level, and the relationship between what you type and
what the controllers transmit can be complicated.
If you have a data-dependent problem you will probably have to do a lot
of testing to find it. If you are lucky, you may manage to find a file
that either can't be sent across your network or takes much longer to
transfer than other similar length files. You can then examine this file
for repeated patterns that you can test using the -p option of smtping.
FILES
/etc/ethers MAC address database
SEE ALSOsmtstat(1), smtconfig(1M), ethers(4)
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