simultaneous file transfer on ethernet (SUN's)

[Art Crotty]

lineater +3



I have a somewhat complex request for info involving file transfer
between hundreds of SUN3 and SUN2 workstations.  These workstations'
are networked together using ethernet (802.3). Protocols - TCP/IP/UDP.

I would like to have the ability to transfer large application
programs to all nodes on the network simultaneously.

Why I think it may be possible to do this:


1.) The ethernet packet information can contain what is commonly
    called a multicast bit within the destination address.  Thus,
    I should be able to set this bit to broadcast or spray my large
    application program (ie. 10mb-30mb) to all nodes on the network.

    I also, using the multi-cast bit, should be able to set up a table
    of nodes that I wish to distribute the program to.  Thus, if
    the bit is set to 0 - it is specific address, 1 it is a group of
    nodes and all 1's in the field indicate all nodes.

2.) Some user-level programs already do something similar to what
    I want.   For instance, "wall" will broadcast a message to nodes
    on your network.  The command "rcp" will copy one or a group of
    files to one particular destination at a time.  I want a "wall"
    or "rwall" and combined "rcp" that can copy my file or files
    simultaneously to all nodes or subgroups of nodes on a network.

I know NFS allows mounting of an application to nodes and simultaneous
access of that application - but that is not what I want.  I want to
distribute to stand-alone machines as well as file servers new copies
of an application once a week and each rcp or "dread the thought"
cartridge taping can consume 1/2 hour per node.  Thus, 20 nodes
is 20 x 1/2 hour by rcp from a master database or less time if multiple
tapes are made or rsh tarring from a server with 1/2" tape.

I would like to be able to say something like:

distribute -g <tablefile> <application> 

where -g is the option for group and tablefile is the database that
contains a list of nodes with names or internet addresses

distribute -a <application>

where -a is for all nodes - no table

I am not that familiar with the networking code on SUN's and was
wondering the following:

Can it be done?

Is this beyond the ability of the Ethernet itself?

When "wall" does a broadcast - is it simultaneous to all nodes or
consecutive?

Will I need some sort of daemon process running, all the time, on
each node waiting for a signal to allow broadcast file transmissions,
or can /etc/inetd already handle this type of request with little or no
code tweeking?

What kind of error checking do I have to do for testing that
the program was successfully transmitted without losing packets
or corrupting packets - at source or destination?

Has anyone created a program that can do this?

If not, can someone get me started as to the process or code that
I might need to access or create to accomplish what I want?

For instance:

you can alter "inetd" or you have to create a new daemon

you must access these libraries and change this/that

you must use these calls

etc., etc.



Thanks in advance for all advice!!!

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