Network Characterization Service (NCS)

Computational Research Division
Lawrence Berkeley National Laboratory

---

Tools based on hop-by-hop network analysis are increasingly critical to network troubleshooting on the rapidly growing Internet. The network characterization service (NCS) provides the ability to diagnose and troubleshoot networks hop-by-hop in an easy and timely fashion. It includes the tools netestand pipechar. Using NCS makes applications capable of fully using the high-speed networks, e.g., saturating 1 Gb/s local network from a single x86 platform.

The algorithms used in release 1.3 (not BETA or earlier) to measure available bandwidth have been mathematically proved to be accurate and non intrusive <2002-12-08> . See results from emulation network Currently, it is implemented for end-to-end measurement in netest revision 2. The hop-by-hop implementation will be in the formal NCS 1.3 release.

This available bandwidth algorithm privodes a new mechanism for designing new network transmission protocol Network Lion .

---

Documentation:

Overview NCS Intro (includes release plan ) netest revision 2 Detailed NCS Information Papers and Talks Tutorials for average user (what is pipechar) Tutorials for experts (partially under construction)

---

API:	NCS Inquiry Protocol [PDF] version contains latest info. [HTML] version Web Query Interface LBNL site

---

Download links:   Available for download are both binaries and source code. If you have any problems, please contact DAAgarwal@lbl.gov.

Supported platforms:		NCS is currently tested on following platforms: FreeBSD (best performances with on NIC timer support) BSD/OS and possible all other BSD O.S.s Linux Mac OS X Solaris AIX IRIX future support: Digital UNIX
		It does not and will not run on T3E because the T3E compiler has no 16-bit integer type. The generic NCS functions should be able to compile and run on platforms that comply with IPv4 standard. Only kernel timer related functions need the FreeBSD KLD mechanism, therefore kernel timer related functions are only available on FreeBSD platform (Mac OS X and other BSD OSs are possibly supportable). However, the on NIC timer feature can be supported for Linux if the sysKonnect driver supports this function under Linux.

---

Emulation Network Topology

Emulation testbed results

 

Utilization % (loss %)	run time (sec.)	netest results	Accuracy		Pathload
GigE network MTU = 9K   50~100 tests per run (300 sec.)	(require longer measurement duration)	available bandwidth (Mb/s)	(%)		Mb/s
					11-13 seconds <possible means guessing>
0 (0)	2.4 - 6.5   including MBS measurement	maximum throughput: 851			N/A
10 (0)					possible > 823
20 (0)		791.0 - 791.2	98.875		possible > 782
30 (0)		690.0- 691.0	98.643		possible > 678
40 (0)		598.5 - 599.0	99.750		possible > 567
50 (0)		502.5 - 502.9	99.420		possible > 480
60 (0)		403.8 - 403.9	99.025		possible > 350
70 (0)		306.4 - 306.6	97.833		possible > 262
80 (0.01)	7.89 (11.9)	210.0 - 211.0 205	94.500 97.500		possible > 217
90 (0.01)	13-15 (26)	113.0 - 115.0 102	86.000 98.000		92.84 - 108.32