Network Characterization Service for Beginner(papers)

 Table of Contents 
 Introduction to NCS 
 How to use NCS 
 NCS HighLight 
 downloading  distribution and re-build binaries

Syntax:
	ncsd [-irtc] [-l] [-max #] [-P #] &

The "-l" option is for overcoming the non responsive and/or troubled network
elements (routers/switches), or firewall. Especially, when you see this message:

 ncsd [1.2 Sep26-2K1] : can't reach the host3[xxx.yyy.xxx.hhh] with max_ttl(#)
 try to analyze partial path instead


 the error message is similar to the pipechar

 pipechar [Mar25-2K1] : can't reach the host3[xxx.yyy.xxx.hhh] with max_ttl(#)
 try to analyze partial path instead


The "-l" option should be used. The recommend arguments are:

	ncsd -l -P 11 -irtc &

The "-max #" is also for the above reason. The recommend value is 25.
When try to use smaller value for "-max", use "-l" with it. These two options
may be forced to use in the future since we have found more and more routers
that send bogus ICMP and TTL to the source.
The less # for "-P" option will make faster initial probing, but may result
in less accurate measurements.

pipechar (a desktop version of NCS) uses these options in the same way.
 tutorial  of these tools explains the pipechar output.

Current ncsd distribution is non-registered version, which runs only in single
server mode. If this is the first time to run ncsd on a host, you may
see the following message:

ncsd [1.2 Sep26-2K1] : no cache file loaded; Error<2> No such file or directory

This is not an error. This tells that it is a new ncsd. Do not try to start
another ncsd, it is already running. You can use ncs client -- ncsC --
to inquire now.


Client:	
Syntax:

	ncsC -s ncsd-name [-ah] [-TCPWin] destination(s)
	ncsC -rm destination(s)
	ncsC -START | STOP destination
	ncsC -chng [train #] [sched interval-tick [start tick]] destination

ncsd-name is the host where you run the NCS daemon (ncsd). You can change the
default ncsd name in ncsC_example.c, line 73, and recompile it:

	{"-s", "%s", 0, 1, 1, "server name", 0, argu_ranges(DEMO_DEF_NCSD)},
to
	{"-s", "%s", 0, 1, 1, "server name", 0, argu_ranges("your_NCSD_name")},

 Most frequently used options:

-ah	will report all hops info.
-TCPWin	will report RTT and Tuned TCP window size for Tx.
-rm	will remove a target from NCS cache. Only the initiator and the daemon
	can remove the target. That is, if a target (destination) is probed
	from host A, then host B will not be able to remove it.  e.g.

	host-A % ncsC target-someone 
IP = ncsd-IP
1 hops to target-someone
hop  1:     xyz.243.2.##: BW avl  99 Mb max  100 Mb;    RTT min 0.4 avg 0.6 ms
hop  1:     xyz.243.2.##: Dynamic bottleneck -- BW 99 Mb
hop  1:     xyz.243.2.##:  Static bottleneck -- BW 100 Mb

	 host-B % ncsC -rm target-someone 
IP = ncsd-IP
ncsC [1.2 Sep25-2K1] : dst xyz.243.2.## failed to remove

 Change path parameters 
	ncsC [-s server] -STOP destination

stops reprobing scheduler for this path on ncsd (server).

	ncsC [-s server] -START destination

starts reprobing scheduler for this path on ncsd (server). Notice that this
command only be executed by the initiator (owner) of the path.

	ncsC [-s server] -chng train length and/or sched interval-tick [start tick]  destination

changes the probe train length, scheduler period, [and the scheduler start time]
on this path. These parameters can be changed in one command or separated
commands. Each tick is 5 minutes. For example:

	ncsC [-s server] -chng sched 10 yahoo.com

changes the scheduling frequency from current to 50 minutes (10 x 5) for path
from server to yahoo.com. The starting time is unknown (whatever left in
previous scheduling).

	ncsC [-s server] 12.34.45.56 -chng sched 10 60

changes the scheduling frequency from current to 50 minutes (10 x 5) for this
path, and start the new scheduling in 5 hours (60 * 5 minutes).


Caution:

	ncsC [-s server] -chng sched 10 100 12.23.34.45

is ok, but

	ncsC [-s server] -chng sched 10 12.23.34.45

will cause error. Put IP before the flag "-chng" in this case.

The default tick time can be changed. Define DEFAULT_SCHED_TIMER in Makefile
or change its value from 300, in ncsd.c, to whatever work for you. Then,
recompile the ncsd -- make ncsd.out .

"-EX" option has the same functionality as "-chng", but it is used only for
initiator. Once the path is initialized, use "-chng" to change parameters.

For other options, type "ncsC -h".

	src/netest/sources/metric/ncs

 ./install.ncs pipechar.out netest.out 

 ./install.ncs 

 Tips  for getting GigE fully utilized: (details are in  papers )

	64-bit/66Mhz PCI
	160-240 MBps memory bandwidth (66-100 MHz main bus)
	300 MBps memory bandwidth (133 MHz main bus)
or
	32-bit/33Mhz PCI
	600 MBps memory bandwidth
or
	use jumbo frame
or
	bad performance (normally is around 380-450 Mbps)