changes

pathrate是pathload的改进型

Changes in 2.4.1 (Jan 2005)
---------------------------
* Modified the sender receiver interaction during retransmission 
  of a lost train. Now receiver sends SEND signal retransmission
  also instead of sender retransmitting in response to NEG_ACK

* Added some debug messages that can be activated by adding -DDEBUG in 
  the makefile

Changes in 2.4.0 (Apr 2004)
---------------------------
* Sender - receiver interaction
  Receiver requests each train and sends ACK or negative ACK.
  Now the receiver will not work with older version of the sender.
* Interrupt coalescence changes
  Detects IC and uses alternate algorithm (Published in PAM '04).
* Minor bug fixes
  - Corrected option (-o <file>) implementation in both sender and receiver

Changes in 2.3.3 (Jan 2004)
---------------------------
* Report ADR as capacity mode only when there is no mode larger than ADR
  (Sometimes ADR mode is narrow even when there exist correct caapcity mode.)

* Bug fixes.
  - Changed exit condition in recv_train function from 
      while ((pack_id<train_len )
    to while ((exp_pack_id<=train_len ); was affecting results in lossy networks.
  - Frees most of the memory allocation now.
  - Slightly modified interrupt coalesence detection.
  - Few print anamolies in gigabit test function.

Changes in 2.3.2 (Jun 2003)
---------------------------
Weiling's changes 2:
* kurtosis instead of ratio of mode_cnt and bell_cnt is used as the narrowness of the bell
  to calculate figure of merit.
* BIN_NOISE_TOLER is modified to be proportional to previous bin_cnt
  instead of a constant.

Changes in 2.3.1 (May 2003)
---------------------------
Weiling's changes 1:
* bin_wd is increased to be twice of the value used earlier
* bell_cnt and index are updated without the previously required condition that
  bin has significant number of measurements.

Changes in 2.3.0 (April 2003):
-----------------------------
* Tested on high capacity paths. (OC-3, OC-12 and Gigabit paths)

* Detects interrupt coalescing. If detected, uses long trains to 
  estimate capacity. (tested on Intel Pro 1000 Gigabit controlor
  82540)

* added command line options to
  - suppress output (-q)
  - get more verbose output (-v)
  - get quick estimate (-Q)
  - write/append output to a file (-o/O)
  - append final outoput in ULM format to a file (-N)

* Receiver uses different thread for control messages while getting probing
  packets in main thread. Don't use select anymore.

* recv_train function return array of packet arrival times.
  
* Sender performs sleep time check before waiting for connection
  from the reciever. Once per sender run, instead of once per connection.

* Abort phase 1 when train length > MAX(max_train_len/4,2)
        rather than when > MIN(max_train_len, 12)

* Fixed the number of pack sizes (to 40) rather than the increament in 
        the packet size (was 25B)

* Fixed small printing bugs

Changes in 2.2.1 (April 2002): 
------------------------------
* limit max train length in PHASE I.
  -  Aborts Phase I 
     when train length > 12. // It's packet-train now and give ADR measurement.

* Dealing with ignored msrments in Phase I changed to:
	Recv pairs/trains in blocks of 27
	At the end of each "block", 
	   if #of ignored msrments > IGNORED_LIM*27
		train_len+=1;
		pack_sz+=200

  ---- fixed small printing bugs.
  ---- Previous version was printing wrong packet sizes.

To-do list :
*) Find a "correct" threshold factor for ignoring msrments.	
*) Find a better binwd


Changes in 2.2.0 (April 2002): 
------------------------------
* select timeout made compatible with Linux 		  	| in _snd.c
* Sender sends abort signal to rcvr to end measurements 
	if it sees too many losses     				| in _snd.c
* Use select in recv_train routine on both the 
	data and control sockets.				| in _rcv.c
* Check TCP socket in recv_train if no data in UDP socket
	Presently and data on TCP socket while expecting a 
	probing packet implies an abort message.		| in _rcv.c
* If(No Phase I mode > ADR && Phase II != unimodal) 
	Then capacity = max_merit(Phase II modes)		| in _rcv.c
* Pathoverflow => go back to prev-train-length && don't change
			train spacing				| in _rcv.c
* Dealing with ignored msrments in Phase I:
	Recv pairs/trains in blocks of 27
	At the end of each "block", 
	   if #of ignored msrments > IGNORED_LIM*27
		train_len+=2;
		pack_sz+=200
	   If train_len > max_train_len	
		train_len=maxtrain_len				| in _rcv.c
* No such measures in Phase II.
* New bin width :
   - 	based on max-min (after removing 10% outliers) 
	instead of ave. 					
   -	Simpler fraction of bw_range				| in _rcv.c
* Preliminary measurements 
   - # of outliers is fraction of measured 			| in _rcv.c
* messages :
   - Show "time" remaining to complete.


To-do list :
*) Find a "correct" threshold factor for ignoring msrments.	
*) Find a better binwd