Ubuntu Manpage: atmtcp - set up ATM over TCP connections

NAME

       atmtcp - set up ATM over TCP connections

SYNOPSIS

       atmtcp [-d] [-v] command ...
       atmtcp -V

DESCRIPTION

The main purpose of atmtcp is to establish TCP connections and to configure them as
virtual ATM devices. Such pairs of "ATM over TCP" devices are connected as if they were
real ATM adapters linked by a cable or fiber, i.e. SDUs sent on a given VPI/VCI are
received at the other end on the same VPI/VCI.

Virtual interfaces and ATM over TCP connections are called links. Other link types
supported by atmtcp are real interfaces, files for recording and playback of ATM traffic,
and printing a hex dump of the PDU content on standard output. Any pair of such links can
be connected with atmtcp. If additional links are attached to such a connection, they
send to all other links, except to the first link and the respective sender, and they
receive from all other links.

atmtcp can operate with two types of virtual interfaces: ephemeral or persistent. By
default, atmtcp interfaces are ephemeral. When the atmtcp process that created an
interface terminates, the virtual ATM device is removed as soon all VCs are closed.
However, if the interface was previously created as a persistent interface, only the
communication stops, but the interface and all VCs on it remain intact. Attempts to send
data on an atmtcp interface in this state fail silently, i.e. the interface behaves just
like a real ATM interface without a wire. A new atmtcp process can then attach to the
interface and resume operation. Persistent interfaces need to be removed explicitly.

If atmtcp has any readable links after processing the command line, it enters a loop to
perform the data forwarding. If no readable links have been specified, atmtcp terminates
after processing the command line. If any setup operation fails, atmtcp terminates at this
point and does not attempt to cancel previous operations (e.g. creation of permanent
interfaces).

OPTIONS

       -d     print detailed progress information on standard error.

       -v     print some progress information on standard error.

       -V     print version number of atmtcp on standard output and exit.

COMMANDS

create [itf]
create a persistent interface. If no interface number is specified, atmtcp uses the
default value 0.

remove [itf]
remove a persistent interface. If the interface is still in use, it is marked as
ephemeral and will be removed as soon as all VCs are closed. If no interface number
is specified, atmtcp uses the default value 0.

virtual [itf]
link to the corresponding virtual (ATM over TCP) interface. If no interface number
is specified, the kernel assigns the first available number.

real [itf]
link to the corresponding ATM interface. If no interface number is specified,
atmtcp uses the default value 0. If a link requests that a VC be opened, atmtcp
will attempt to open a VC with the specified QoS parameters on that interface. If
the operation succeeds, data can be sent or received on that VC. If the operation
fails, an error code is returned to the requester. Note that only data arriving on
open VCs can be received and that a real ATM interface never initiates a
connection. atmtcp can share ATM interfaces with other applications.

connect host [port]
connect to an instance of atmtcp running on the specified host. If the port
argument is omitted, atmtcp uses the default port 2812.

switch host line [port]
like connect, but connects to an ATM over TCP "switch" and selects the specified
virtual line.

listen [port]
listen for an incoming ATM over TCP connection. If the port argument is omitted,
atmtcp uses the default port 2812. atmtcp waits until the connection is
established. Only one connection is accepted per listen command.

listen-bg [port]
like listen, but run in background after beginning to listen.

read file [stream]
play back all streams from the specified file. If a stream number is specified,
only that stream is played back.

write file
record the traffic of all links in the specified file. The PDUs from each link are
stored in a stream with the same number as the link.

print print a hex dump of the content of all received PDUs on standard output.

bg continue to run in background (i.e. in a forked child process).

wait [seconds]
wait for the specified number of seconds. If no time is specified, atmtcp waits for
a newline on standard input.

RESTRICTIONS

       Due  to  recent protocol changes, atmtcp is currently not compatible with the ATM over TCP
       "switch".

       Only AAL SDUs are exchanged, no segmentation or reassembly  is  performed.   That  implies
       that  using  different AALs (e.g. AAL5 and AAL0) on either side will reveal limitations of
       this emulation.

       The atmtcp process needs to run during the the whole lifetime of the connection.

EXAMPLES

       Create a pair of virtual ATM over TCP interfaces on the local host and connect them:

         # session A
         atmtcp virtual listen
         # session B
         atmtcp virtual connect localhost

       Create virtual interface 1, connect it to real ATM interface 0, then start atmsigd on  the
       virtual interface, and log all the traffic in a file:

         atmtcp virtual 1 real 0 write /tmp/log
         atmsigd 1.0.5

       Take the previously created file and examine the traffic sent from atmsigd using saaldump:

         # session A
         atmtcp virtual 1 read /tmp/log 0 wait
         # session B
         saaldump 1.0.5
         # press [Enter] in session A

AUTHOR

       Werner Almesberger, EPFL ICA <Werner.Almesberger@epfl.ch>