Saturday, March 24, 2007

Blogosphere paper

Duarte, Fernando; Mattos, Bernardo; Bestavros, Azer; Almeida, Virgilio; Almeida, Jussara. Traffic Characteristics and Communication Patterns in Blogosphere, December 15, 2006.
http://www.cs.bu.edu/techreports/pdf/2006-033-blog-characterization.pdf


nice paper !
The paper discuss about traffic characteristics of blogosphere. Some important notes:
- Marginal distribution of transfer size, it show heavy tail ! near to pareto distribution.
- Access patterns (bytes transfer, #distinct blogs accessed with read/write request, and # read/write request sent by blogosphere visitors) show diurnal pattern !

Tuesday, March 20, 2007

Ribut-ribut soal dns record SBY

Ribut-ribut soal situs SBY yang katanya di hack padahal ternyata DNS nya yang di hack, apa saatnya deployment DNSSEC dimulai ?
pro dan kontra DNSSEC:
Pro:
1.Adanya tambahan fitur keamanaan pada DNS zone sehingga zone relatif sulit di-spoof
2.Tidak perlu upgrade software karena BIND sebagai software DNS terbanyak dipakai sudah mendukung DNSSEC
Kontra:
1.Belum ada aplikasi yang mendukung DNSSEC (web browser, MTA, etc)
2.DNSSEC menaikkan volume traffic DNS



Referensi:
[1] http://www.potaroo.net/ispcol/2006-10/dnssec3.html
[2] http://www.potaroo.net/ispcol/2006-09/dnssec2.html
[3] http://www.potaroo.net/ispcol/2006-08/dnssec.html

Thursday, March 15, 2007

Tokyo Metro Subway di cover oleh WiFi

Berhubung akhir-akhir ini sering menggunakan Tokyo metro subway: chiyoda-line, hibiya-line. Saya melihat rupanya beberapa station Tokyo metro subway tercover oleh WiFi (sponsor oleh B-Flets nya NTT).

Heavy-Tail Phenomena: Probabilistic and Statistics Modelling

Finally, Media Center Keio SFC bought:
heavy-tail phenomena: probabilistics and statistics modelling. Sidney I.Resnick. Springer series in Operations Research and Financial Engineering.

Monday, March 12, 2007

Blog yang satu lagi

blog saya yng satu lagi [1], disebelah saya ini [1] rencananya mau dipakai buat summary materi Internet Traffic Measurement, Analysis, and Modelling. Berhubung di wordpress bisa nge-LaTeX [2]




[1] http://dikshie.wordpress.com
[2] http://faq.wordpress.com/2007/02/18/can-i-put-math-or-equations-in-my-posts/

Sunday, March 11, 2007

AsiaBSDCon 2007 (2)

Pada hari kedua AsiaBSDCon 2007 ini seperti sebelumnya saya berangkat pagi jam 07.20 Odakyu rapid express dari Shonandai-eki. Namun pagi ini kawasan Kanto diguyur hujan lumayan membuat beberapa bagian celana saya agak basah.

Acara pembukaan oleh George V Neville Neil dng membacakan agendar hari ini. Presenter pertama Ryan McBride (OpenBSD) berbicara dng topic Randomness. Presenter kedua Keiichi Shima (KAME, IIJ) berbicara dng topic Mobile IPv6.

Lunch masih dengan sama seperti kemarin bento dengan dua pilihan plus ocha (green tea).

Sesi berikutnya setelah makan siang: dongeng sejarah BSD Unix oleh Marshall Kirk McKusick. McKusick juga menjual DVD history of BSD Unix di stand Google, yng menjual adalah Murray Stokeley (src commiter FreeBSD yng sekarang kerja di Google dng jabatan di Google,Inc sbg site realibility) hasilnya sold out ! sial saya nggak kebagian, si Ume ngeborong euy, dia beli 2 biji DVD !!! . Oh ya disesi McKusick ini McKusick cerita mengapa DARPA memilih Unix BSD sbg Internet server ARPANET yaitu pihak BBN sbg kontraktor TCP/IP ternyata kerjaannya payah, Bill joy yng mewakili Berkeley pada waktu itu menolak perintah DARPA utk memasang TCP/IP nya BBN di BSD Unix karena menurut Bill Joy TCP/IP buatan BBN kalah performance dng TCP/IP nya Berkeley. Selain itu juga krn Unix AT & T yng sempat ditest oleh pihak DARPA sbg Internet server ternyata harus di reboot sebanyak dua kali ! sedangkan Unix BSD anteng-anteng saja :-) krn dua alasan tsb itulah pihak DARPA memilih Unix BSD sbg Internet server ARPANET bahkan berlanjut hingga NSF-Net.
Presenter berikutnya Stephan Uphoff (Yahoo!, Inc) dng topic Bluffs. Lalu presenter selanjutnya Koshiro Mitsuya (Keio University, ini sih senpai saya di lab) dng topic Dualstack mobile IP.

Coffee break lalu lanjut sesi presentasi. Presenter pertama Mathieu Sauve-Frankel (OpenBSD) dng topic IPSec. Lalu selanjutnya Randall Steward (Cisco System) dng topic SCTP.

Coffee break lagi (tapi saya ngantuk :) padahal menu coffee breaknya kopi pahit starbuck), terus lanjut sesi presentasi lagi. Presentasi pertama Damien Miller (OpenBSD) dng topic OpenSSH. Presenter terakhir Pawel Jacub Dawidek dng topic ZFS.
Pawel terpaksa mendemonstrasikan operasi ZFS di notebook Apple Robert Watson karena Pawel kesulitan dalam mengkonfigurasi ukuran font pada notebooknya. :-)

Ok acara conference selesai, saatnya dinner :-) oh ya sebelum diner ada penutupan dr George V Neville Neil. ya intinya terima kasih kpd sponsor, panitia, peserta, dan speakers. George juga cerita dia dan Hiroki Sato (hrs) sempat panik karena pada hari terakhir pemasukkan paper tidak ada satupun yang setor. Dia bilang: "Oh my God, what kind of conference without papers !"

Oh ya beberapa info penting:
Pawel akan segera meng-committ ZFS ke HEAD, katanya sih dalam waktu 1 bulan kedepan.
Sthepan Uphoff juga sewaktu saya tanya pas dinner kapan mau commit Bluffs ke HEAD, dia bilang summer 2007 ini paling cepat krn masih ada beberapa constraints seperti kode bluffs yng masih banyak bug, lalu ada rencana 7.0 release pada bulan Juni 2007 ini.

Saturday, March 10, 2007

AsiaBSDCon 2007 (1)

Hari ini Sabtu tgl 10 Maret 2007 saya hadir di AsiaBSDCon2007 conference bertempat di Tekeda Building, The University Tokyo. Acara dimulai jam 09.00, jadi saya mesti berangkat dari shonandai-eki (sta terdekat dng apato saya) jam 07.20 naik odakyu rapid express sampai Yoyogi Uehara -eki lalu norikae (transfer) ke Chiyoda -sen lalu turun di Nezu-eki lalu jalan kaki kurang lebih 8-10 menit sampai Takeda Building. Eh sebenarnya ditengah perjalanan dari Yoyogi Uehara-eki ke Nezu-eki saya sempat turun di Hibiya-eki karena tiba-tiba perut saya tidak bisa diajak kompromi, terpaksa turun di Hibiya-eki untuk cari toilet lalu setelah selesai berkompromi dengan perut dan sistem pencernaan tubuh saya lanjutkan perjalanan ke Nezu-eki.
Sebenarnya acara AsiaBSDCon2007 ini dimulai sejak tgl 8, hanya saja tgl 8 dan 9 Maret adalah sesi tutorial dan biaya tutorial dan conference berbeda jadi saya putuskan ikut conference saja krn saya lagi ndak punya duit, utk hadir di conference pun saya dibiayai oleh boss saya assistant profesor di Keio Univ, SFC, Achmad Husni Thamrin.
*many thanks to my boss* !!!

Acara dimulai pembukaan oleh George V Neville Neil (gnn at FreeBSD.org) dan dari local host chair. Oh ya gnn ini rupanya dapat ngobrol menggunakan bhs Jepang dng lancar krn pernah tinggal di Jepang selama 3 tahun !

Saya melihat kehadiran developer *BSD seperti Kirk McKusick (ini mah veteran ! rambut udah beruban !), Robert Watson (FreeBSD's netperf), Pawel Jakub Dawidek (yng porting ZFS ke FreeBSD), Brook Davis (spesialis clustering), lalu ada Itojun (tangan kanannya di gips krn cedera, sehingga hanya tangan kirinya saja yng berfungsi utk sementara), Jinmei Tatuya (ISC,Toshiba), Murray Stokely (now he works at Google, Inc), Ryan McBride (OpenBSD's pf and Carp author), Hajimu Umemoto (ume at FreeBSD, IPv6), Randall Steward (SCTP author, Cisco System,Inc), Xin Li (dari China) dan masih ada beberapa orang lagi.

Menu lunch: bento dengan dua pilihan (dua pilihan bukan berarti bisa ambil dua-duanya ! cuma boleh ambil salah satu saja) Sedangkan menu coffee break: starbuck coffee. Acara conference diakhiri presentasi dari sensei saya Prof Jun Murai :-) dan dinner (banquet). Selama makan malam saya lihat Jun Kuriyama (FreeBSD's port committer, IMRGSRC, Inc Japan) jadi tukang bersih-bersih, bolak balik mengambil sampah yng berceceran dan piring kotor.

Iseng-iseng biar blog ini keliatan penuh :-) saya copy and paste perintah ifconfig:
-------------------------------------------------------------------------------------------------------------
ath0: flags=8843 metric 0 mtu 1500
ether 00:0a:79:6b:4e:cf
inet6 fe80::20a:79ff:fe6b:4ecf%ath0 prefixlen 64 scopeid 0x3
inet6 2001:200:161:10:20a:79ff:fe6b:4ecf prefixlen 64 autoconf
inet 192.51.215.203 netmask 0xfffffc00 broadcast 192.51.215.255
media: IEEE 802.11 Wireless Ethernet autoselect (OFDM/36Mbps)
status: associated
ssid uttakeda1110 channel 1 bssid 00:15:63:11:a0:b0
authmode OPEN privacy ON deftxkey 1 wepkey 1:40-bit txpowmax 36
bmiss 7 protmode CTS burst roaming MANUAL bintval 100
-------------------------------------------------------------------------------------------------------------

Ruangan conference sih cukup bagus dan representatif, cuma ada sedikit masalah dng sound system.

Oh ya rupanya Google skr sudah menjadi salah satu sponsor FreeBSD project dan juga sbg FreeBSD user. Apa ini gara-gara si Murray Stokely kerja di Google ? saya ndak tau :-)

Tuesday, March 06, 2007

Some interesting articles from IEEE Communications Magazine

I found interesting articles on IEEE Communications Magazine, January 2007, Vol.45, No.1
1.Connectivity in emerging regions: need for improved technology and business models. By Rahul Tongia, Carnegie Mellon University.
"The digital devide is pressing challenge for both technology and policy professionals. Connectivity is one aspect of the devide, albeit an important one. Availability and affordability remain important issues but these depend on not only technology choices but also business and regulatory models."

2.Experiences in using WiFi for rural Internet in India. by Bhaskaran Raman and Kameswari Chebrolu, Indian Institute of Technology, Kanpur.
"Acess to communication can play pivotal role in the socio-economic development of rural regions in the third world. For affordability, the choice of technology to achieve this is a significant factor. The authors have choosen IEEE 802.11 as a cost effective technology to provide rural connectivity in the context of two projects."


3.WiFiRe: Rural area broadband access using the WiFi PHY and a multisector TDD MAC. by Krishna Paul (Intel), Anitha Varghese (General Motors Research), Anurag Kumar (Indian Institute of Science, Bangalore), Sridhar Iyer (Indian Institute of Technology, Bombay), and Bhaskar Ramamurthi (Indian Institute of Technology, Madras).
"The needs of India rural telecom, and the economics of currently available broadband access technologies, motivate a new system for rural broadband access, which the authors call WiFiRe (WiFi Rural Extension). The system leverages the widely available and highly cost reduced, WiFi chipset. However, they retain only the PHY from these chipsets and propose a single-channel, multisector, TDD MAC using directional antennas."


4.Remote Locations Coverage Analysis with Wireless Mesh Networks Based on IEEE 802.16 Standard. By Roberto Hincapie and Javier Sierra (Universidad Pontifica Bolivariana), and Roberto Bustamante (Universidad de los Andes).
"The authors analyze the wireless coverage problem of remote regions with low user density and propagation problem due to irregular terrain and high tree density. The use of a wirelss mesh network is proposed as a solution."


5.Potential of CDMA450 for rural network connectivity. By Sergiu Nedevschi, Sonesh Surana, Bowei Du, Rabin Patra, Eric Brewer (UC Berkeley), and Victor Stan (Zapp Telemobil).
"The authors evaluate CDMA450 as a potential solution for rural data and voice connectivity. They analyze the main stength of CDMA450 and some of the potential limitations for rural coverage, both from technical and economic standpoint."

6.The Ad-Hoc Return Channel: a Low cost solution for Brazilian Interactive Digital TV. by Miguel Elias M. Campista, Igor M. Moraes, Pedro Miguel Esposito, Aurelio Amodei Jr., Daniel de O. Cunha, Luis Henrique M.K. Costa, and Otto Carlos M.B. Duarte (Universidad Federal do Rio de Janeiro).
"The upcoming terrestrial digital television technology brings a new class of services to traditional TV sets. A set top box may, for example, access the Internet and send email. The interactive return channel makes these new services possible. The authors analyze the viability of a wireless ad hoc network to implement the return channel.

7.BusinessFinder: Harnessing presence to enable live yellow pages for small, medium, and micro mobile business. by Dipanjan Chakraborty, Koustuv Dasgupta, Sumit Mittal, Archan Misra (IBM Research), Anuj Gupta (IBM Software), Eileen Newmark (IBM systems and technology), and Christopher L. Oberle (IBM global services).
"The authors present BusinessFinder, a service that leverages the underlying cellular presence subtrate to provide efficient, on-demand, context aware matching of customer request to nomadic micro businesses as well as small and medium businesses having a mobile workforce.

Friday, March 02, 2007

UCSD Network Telescope

I got from CAIDA:

http://www.caida.org/data/realtime/telescope/

nice monitoring !

Finally ITB got IPv6 address from APNIC

> whois -h whois.apnic.net 2403:8000::
% [whois.apnic.net node-2]
% Whois data copyright terms http://www.apnic.net/db/dbcopyright.html

inet6num: 2403:8000::/32
netname: BANDUNG-NET-20070302
descr: --------------------------
descr: Institut Teknologi Bandung
descr: Jl. Ganesha 10
descr: Bandung 40132
descr: INDONESIA
descr: --------------------------

Thursday, March 01, 2007

Microsoft's money

I read article on Communications of the ACM February 2007, Volume 50 Number 2
"What road ahead for Microsoft the Company?" by Michael Cusumano (Professor at the MIT Sloan School of Management and author of the Business of Software, Free Press, 2004).

Microsoft revenue breakdown:
FY06 sales = $44.3 billion, Op.Income = $16.6billion (37%)
Corporate expenses = $5 billion (11%)
R&D expenditure = $6.6 billion (15%)

o Client (Windows): $13.2 billion revenue, $10.2 billion op income
o Office+:$11.8 billion revenue, $8.2 billion op income
o Server and Tools: $11.5 billion revenue, $4.3 billion op income
o Business Solutions: $919 million revenue, $24 million op income
o MSN: $2.3 billion revenue, -$77 million op income
- 30% access
- 10% suvbscriptions and transactions
- 60% advertising
o Mobile and Embedded: $377 million revenue, $2 million op income
o XBox, PC Games: $4.3 billion revenue, -$1.3 billion op income


How Microsoft makes money:
o Products (91%) + MSN (5%), Services (4%)
- Sales: Windows (30%), Office (27%), Servers (26%)
- Gross Profits: Windows (47%), Office (38%), Servers (20%)
- Gross Margins: Windows (77%), Office (70%), Servers (37%)
o OEM Software Revenues = 34% of sales
- 80% Windows, 20% Oiffce, 10% Servers, 100% mo/emb
o Enterprise Software Revenues
- 50% Office, 90% servers, 100% BizSolutions
- Multi-year software licenses = 24% of total sales (50% servers, 50% Office)
o Consumer Software Revenues = 27% of sales
- 40 % Office, 20% Windows, 100% Home/Entertainment

Some papers on spam

I read Communications of the ACM, February 2007 Volume 50, Number 2.
"SPAM and The Ongoing Battle for the Inbox".
by Joshua Goodman, Gordon V. Cormack, and David Heckerman.

this article describe some techniques on anti-spam by reviewing some papers on references and their experience research on Microsoft
---------------------------------------------------------------------------------------------------------------
Even as spammers and phisher try ever more sophisticated techniques to get past filters and into users mailboxes, anti-spam researchers have managed to stay several steps ahead so far.

References:
[1] Bratko, A., Cormack, G., Filipic, B., Lynam, T., and Zupan, B. Spam filtering using statistical data compression models. Journal of Machine Learning Research 7 (Dec 2006).
[2] Chellapila, K. and Simard, P. Using Machine learning to break visual human interaction proofs. In proceeding of the advances in Neural Information Processing Systems (NIPS) conference (Vancouver, Canda). MIT Press, 2005, 265-272.
[3] Chellapila, K, Simard, P., and Czerwinski, M. Computer beat humans at single character recognition in reading based human interaction proofs (HIPs). In proceeding of the second conference on Email and Anti-Spam (CEAS) (Palo Alto, CA, July 21-22, 2005).
[4] Dwork, C. and Naor, M. Pricing via processing or combatting junk mail. In proceedings of the 12th Annual International Cryptology Conference (Lecture Notes in Computer Science) (Santa Barbara, CA, Aug 16-20). Springer, 1992, 137-147.
[5] Goodman, J. and Rounthwaite, R. Stopping outgoing spam. In proceedings of the ACM conference on Electronic Commerce (EC'04) (New York, May 17-20). ACM Press, New York, 2004, 30-39.
[6] Hulten, G., Penta, A., Seshadrinathan, G., and Mishra, M. Trends in spam products and methods. In proceeding of the first conference on Email and Anti-Spam (CEAS) (Mountain View, CA, July 30-31, 2004).
[7] Kolcz, A., Chowdhury, A., and Alspector, J. The impact of feature selection on signature-driven spam detection. In proceedings of the first conference on Email and Anti-Spam (CEAS) (Mountain View, CA, July 30-31, 2004).
[8] Messaging Anti-Abuse Working Group. MAAWG Email Metrics Program, First Quater 2006 Report June 2006;http://www.maawg.org/about/FINAL_1Q2006_Metrics_Report.pdf
[9] Naor, M. Verification of a Human in the Loop or Identification via the Turing test; http://www.wisdom.weizmann.ac.id/~naor
[10] Rigoutsos, I. and Huynh, T. Chung-Kwei. A pattern discovery based system for the automatic identification of unsolicited e-mail messages. In proceedings of the first conference on Email and Anti-Spam (CEAS) (Mountain View, CA, July 30-31, 2004).
[11] Sahami, M., Dumais, S., Heckerman, D., and Horvitz, E. A Bayesian approach to filtering junk e-mail. In Learning for text categorization-Papers from the AAAI workshop. AAAI technical report WS-98-05 (Madison, WI, 1998).
[12] Yih, Y., Goodman, J., and Hulten, G. Learning at low false positive rates. In proceedings of the third conference on Email and Anti-Spam (CEAS) (Mountain View, CA, July 27-28,2006).

Buffer Sizing Strategies

I read this paper:
"A critique of recently proposed buffer-sizing strategies", G.Vu-Brugier, R.S.Stanojevic, D.J.Leith, R.N.Shorten. ACM Computer Communication Review, Volume 37, Number 1, January 2007.

here I re-write again the big picture:
-------------------------------------------------------------
background:
Buffers are used at network routers to temporary store incoming packets when the arrival of packets received exceeds the capacity of the egress link. This is done to maintain high level of utilization link capacity and to accommodate bursty traffic. Traditionally, router buffers have been provisioned according to the bandwidth delay product (BDP) rule: namely, one chooses the buffer size as B x T, where B is the rate of the link served by the router, and T is the "typical" round trip time experienced by connections utilizing the link. Building upon the basic observation that, under some circumstances, only a fraction of TCP flows reduce their sending rates in response to a single congestive event, a number of recent papers have suggested the possibility of deploying significantly smaller buffers without compromissing utilization of a congested link.

testbed measurements
using PC with FreeBSD and ADT algorithm for buffer sizing measurement

impact of very small buffer
it might be tempting to simply choose small size of buffer and accept the cost of reduced utilization during period with few flows. Particular note was the negative impact of very small buffers on link quality.
measurement shows with a buffer size only 3KB (or two 1500 bytes packets) it can be seen that the packet loss remains persistently high (at around 20%) while link utilization remains consistently below 60%. This test was performed during the day and can be compared to hours 1-14. Due to the large number of user complaints concerning link quality during this test, the test was terminated after 2,5 hours.

conclusions
1.Real links contain a complex mix of flow connection lengths and round trip times.
2.Traffic patterns change significantly (here significantly is with respect to buffer sizing requirements) over time.
3.In the context of buffer sizing it is essential to distinguish between links at which TCP flows experience packet loss and those where they do not. On over provisioned links that experience essentially no queuing and generate essentially no packet loss the choice of buffer size has little impact on performance. We contrast this with access links where significant queuing and packet loss occurs.
4.Packet loss is an important aspect of link quality in practice. We illustrate this in the context of the use of a very small queue on a live production link - we had in fact to end our test prematurely (after 2.5 hours) owing to the high number of user complaints regarding link quality when using a very small buffer.
----------------------------------------------------------