[ns] Changing the header size for one-way TCP

[Sally Floyd <floyd@aciri.org>]

I have just checked in a change to the one-way TCP in NS, so that
the header size of the TCP/IP header is now taken into account in
computing the size of the packet in bytes transmitted on the link.

The log entry in CHANGES.html is below.

*This will change the output of tests that you run on NS.*
To get the old output, add the following line:
   Agent/TCP set useHeaders_ false.

As usual, variables that have had their default values changed are
commented in tcl/lib/ns-default.tcl.

- Sally

[Sally Floyd] Wed Nov 28 2001
Changed the default for "useHeaders_" in Agent/TCP to true. 

[floyd] Tue Nov 27 13:34:43 PST 2001 
Added an option "useHeaders_" to one-way TCP that takes into account
the TCP/IP header size in bytes when computing the size of the
packet to be transmitted on the wire. The current default is for
this to be false, but at some point the default will be changed.
The validation test is "./test-all-simple statsHeaders" in tcl/lib.