Re: [ns] error using TCP/Sack1 agent

[Sally Floyd <floyd@aciri.org>]

Lloyd -

>Would it be feasible to set the scoreboard on a per-agent basis from a
>bound variable ...

The ideal solution, for saving memory in running very large
simulations, would probably be for the ScoreBoardNode (SBN) array
to be only created when needed, because a TCP that never had any
packets dropped would never need a scoreboard at all, I guess.

And, the maximum scoreboard size needed by the SACK TCP sender
should be directly related to the maximum window.

For example, I set
  #define SBSIZE 10000
because I run simulations where I set:
  Agent/TCP set window_ 10000

One-way TCP being as it is, this maximum window size is configured
as a property of the TCP sender, not the receiver.  So the TCP
sender in NS knows the maximum window size, and should therefore
also know the maximum size needed for the SACK scoreboard.

(malloc is already used for arrays in NS, e.g., in tfrc-sink.cc.)

Still, it needs someone to actually do it...

- Sally