IGI/PTR v2.1

IGI/PTR is an end-to-end available bandwidth measurement tool, it implements two algorith: IGI (Initial Gap Increasing) and PTR (Packet Transmission Rate). For more details, see http://www.cs.cmu.edu/~hnn/igi.

WHAT'S NEW
==========
org: This version improves IGI/PTR's performance on high-loaded paths (say 80% of utilization). Compared with the previous version, this version can obtain more accurate estimation. See ChangeLog in the source tar-ball for detailed changes.

new in this repo:
Modified get_time to use kernel timestamps (SO_TIMESTAMPNS) for receive time recording or otherwise use clock_gettime. Modified server to pass back nano-precision timestamps instead of micro-precision. Modified TCP port to always use port 8889 and udp port starting from 8890. Disabled debugging symbols and enabled compiler optimization. Removed use of delay_num busy loop and used get time busy loop for gap generation.

BUILD
=====
On Linux, "make" should just work.
(Unlike the previous version, I only have time to test it on linux. It should be trivial to make it compile on SUN and FreeBSD if it doesn't yet. See the Makefile for detailes.)

RUN
===
IGI/PTR needs to run on the two end points of a path, with ptr-client on client side (sending probing packets), and ptr-server on server side (recording probing packets' arriving timestamps). 

NOTE: the probing direction is ptr-client -> ptr-server, 

On server:

	ptr-server [-vdh]

	-v 	verbose mode
	-d 	debug mode (will print more message than verbose mode)
	-h 	Usage message.

On client:

	ptr-client [-n probe_num] [-s packet_size] [-p dst_port]
	           [-k repeat_num] [-f trace_file] [-vdh] dst_address

	-n      set the number of probing packets in each train [60]
	-s      set the length of the probing packets in byte [500B]
	-p      indicate the dst machine's listening port [10241]
	        This is optional, it can itself search for the port
	        that the igi_server is using.
	-k      the number of train probed for each source gap [3]
	-f      dump packet-level trace into trace_file
	-v      verbose mode.
	-d      debug mode.
	-h      print this message.
dst_address     can be either an IP address or a hostname


OUTPUT
======
Here is an output example in verbose mode. The [* *] is the explaination for 
the output.

*. client side output (verbose mode):

	unix> ./ptr-client -v 128.2.191.38
	src addr: 128.2.222.152
	dst addr: 128.2.191.38
	we get str: READY
	probing_port = 10242
		[* basic probing setup information			*]
	 
	probe_num = 60 packet_size = 500 delay_num = 0
		[* statistics for single probing phase, "delay_num" is  *]
		[* the loop count used to generate the source gap	*] 
	from dst: data_size = 720 total_count = 60
		[* some info for the feedback from dst, "data_size" is 	*]
		[* the size of data got from dst, "total_count" is 	*]
		[* number of probing packet the dst receives 		*]
	gaps (us):     4    45 |     4    45
		[* src_gap(us) and dst_gap(us) for this probing. 	*]
	 
	probe_num = 60 packet_size = 500 delay_num = 0
	from dst: data_size = 720 total_count = 60
	gaps (us):    10    88 |     5    43
	 
	probe_num = 60 packet_size = 500 delay_num = 0
	from dst: data_size = 720 total_count = 60
	gaps (us):    15   131 |     5    43
	------------------------------------------------------
	 
	......
	(here we remove the outputs for 4 more source gap samples )
	......
	 
	probe_num = 60 packet_size = 500 delay_num = 42
	from dst: data_size = 720 total_count = 60
	gaps (us):    61    57 |    61    57
	 
	probe_num = 60 packet_size = 500 delay_num = 42
	from dst: data_size = 720 total_count = 60
	gaps (us):   122   114 |    60    57
	 
	probe_num = 60 packet_size = 500 delay_num = 42
	from dst: data_size = 720 total_count = 60
	gaps (us):   182   171 |    60    57
	------------------------------------------------------
	smaller dst_gap, considered to be equal
	 
	PTR:  93.295 Mpbs (suggested)
	IGI:  94.392 Mpbs
		[* the final measurement 				*]
	Probing uses 0.401 seconds, 18 trains, ending at a gap value of 128 us.
		[* statistics for the whole probing procedure		*]

*. server side output (verbose mode):

	unix> ./ptr-server -v
	server port = 10241 
		[* probing server listening here 			*]
	get new connection 
	src_ip_str = 128.2.198.120 
	dst_ip_str = 128.2.191.38 
	waiting for START msg
	probe_num = 60 
	create a new filter item
	listening port = 10242 
		[* this UDP port number that client is going to send	*]
		[* probing packet to 					*]
	come into get_packets 
	start sending back data
	start sending back data
	start sending back data
		[* except the ip addresses and port numbers, the other 	*]
		[* information is not important unless you want to know *]
		[* how the source code works 				*]

KNOW PROBLEMS
=============
*. When _all_ packets in a packet train get lost, ptr-client will stuck.

CONTACT
=======
Please send any bugs to hnn@cs.cmu.edu.

[Wed May  3 13:04:16 EDT 2006]