Doctorate in electrical engineering, Columbia
Masters Degree in EE (with distinction), Netherlands Universities, 1977.
Bachelor of Technology in EE, Indian Institute of
Technology, New Delhi, 1975.
Krishan is currently a research VP responsible for research on NFV and web communications. He also manages award programs such as Bell Labs Fellows. He was Vice President of Networking Research at Bell Labs from
Jan. 2000 to Sept. 2013. In that role, he managed all networking research in
Bell Labs, comprising nine departments in seven countries: USA, France, Germany,
Ireland, India, Belgium, and South Korea.
Upon his graduation in 1981, he joined Bell Labs,
Murray Hill, New Jersey as a Member of Technical Staff and was promoted to
Department Head in 1993. He was named VP
of Networking Research in 2000. He is
also an Adjunct Professor at Columbia University and an honorary professor at
Krishan has made many
seminal contributions to the Internet infrastructure design, protocol design,
and wireless networks. Here is their summary.
Internet infrastructure Design:
Krishan (with T. V. Lakshman and T. Woo) made
a breakthrough in Internet re-design.
The main idea behind this work was to separate control functions and
complex software from the forwarding portions on Internet routers. This work
made it possible for forwarding technologies (e.g., different link layer and
switching protocols) to evolve and be deployed independently from control
protocols (e.g., routing, security).
This contribution is a precursor to the current Software Defined
Networking (SDN) revolution. A patent based on this work won the 2010 Edison
Krishan also made many seminal contributions to protocol design
and analysis. His early work focused on
formal methods such as efficient algorithms for validation of communication
protocols, conformance of implementations to design, and automated methods for
constructing protocol convertors. His
work started a new testing research area and the widespread use of formal
testing throughout the telecommunications industry. Krishan has designed several breakthrough protocols. His work has led to one of the most popular
reliable multicast transport protocols (RMTP) and a revolutionary high speed
transport protocol (SNR).
developed techniques and tools for conformance testing, protocol verification,
protocol conversion, and reverse engineering. Until early 90’s conformance
testing typically used ad-hoc
techniques. Krishan’s work was the first effort to invent formal methods for
this area. It introduced the notion of unique signatures for states: Unique
Input Output (UIO) sequences. These techniques resulted in a more complete
testing capability and a reduction in test time from weeks to a few hours. It
was instrumental in the creation of a new research field: formal methods for
conformance testing. It generated a number of doctoral thesis and hundreds of
follow-up papers. It resulted in a tool used in AT&T for conformance
testing of all ISDN and ATM standards. UIO sequences has become a
well-accepted term. Follow-up research has resulted in terms such as partial UIOs, multiple UIO, etc.
Krishan’s pioneering work, large-scale deployment of reliable multicasting was
considered to be difficult because of
problems associated with maintaining the necessary state for making multicasts
reliable. Because of the prevalence of low-bandwidth network links in the
mid-1990s, multicasting was essential for many applications such as maintaining
consistent billing information. Despite the need for deploying a scalable and
reliable multicast infrastructure, the lack of a scalable protocol made
commercial deployment impossible. Krishan’s research resulted in the creation
of a new protocol, Reliable-Multicast-Transport-Protocol (RMTP) that enabled
reliable multicasting of data over the Internet. He invented a new technique to avoid the
problem of too many feedback messages; this makes multicast intrinsically
scalable. Krishan’s research has also been very influential in the area of
multicast congestion control; he helped develop fundamental ideas on extending
TCP like congestion control mechanisms to multicasts.
RMTP has been deployed in AT&T’s billing
network, where very high reliability and scalability are imperative. It was
used to distribute billing records from AT&T’s core switching machines
(such as 4ESS switches) to several billing systems and backup systems. This
system must be up continuously; any downtime would lead to enormous losses.
This work resulted in the formation of a successful new company -- Globalcast
--which was later acquired by Talarian.
created a revolutionary high-speed transport protocol. The key idea was to
create a protocol that is not reactive, but instead periodically exchanges
state information to greatly increase throughput. This was a breakthrough in
transport protocol design, as the prevailing view of transport protocols at the
time was to design them to react to key events, such as data reception or loss.
The main concept from this protocol was incorporated in the SSCOP protocol, a
standard used in high-speed ATM networks. SSCOP was used in thousands of ATM
networks deployed around the world. This work also resulted in the Leonard G.
Abraham Prize Paper Award and the best paper at ACM SIGCOMM 1989.
In 1995, Krishan initiated a project on wireless
messaging long before text messaging had become popular, and before email was
delivered to cell phones and mobile web browsing was possible. This project resulted in outstanding research
results that were published in many top conferences and journals, several
patents, and finally the first product from Lucent for the Mobile Internet
market. The novelty in this work was
designing systems that adapted content so that a rich set of features could be
used on simple wireless devices. This
included the introduction of thin clients in mobile phones, novel methods of
encoding messages and responses, and the transformation of email and web
content to fit cell phone screens.
Krishan devised a novel way to much more efficiently
route voice traffic in a wireless packet network. The main idea of the work was to allow wireless packet voice traffic to
remain in its native mode as it traversed the network thus saving network
resources and improving the quality of voice by eliminating unnecessary voice
coding. These ideas are implemented in
all 3G and 4G networks. The patent was awarded the Thomas Alva Edison Patent
Award in 2005.
The modularization of call processing software also eased
the ability to perform protocol interworking.
Krishan recognized that as wireless networks continued to mature, and as
new wireless networks were introduced, interworking between these systems
became of paramount importance. He
combined his expertise in protocol conversion with modular call processing to
invent a system which enabled global roaming by connecting disparate wireless
networks and allowing them to easily interwork.
This work was not only built upon fundamental research results, but led
to a product line which now supports over 400 million subscribers. This also won the Thomas Edison Patent Award
Honors and Awards
The 2005 IEEE Eric E. Sumner Award for
“Seminal contributions to networking protocols.”
The 2005 IEEE W. Wallace McDowell Award for
“Seminal contributions to networking protocols and wireless data networks.”
Inducted into the NJ Inventors Hall of Fame, 2014.”
The 2005, 2009, and 2010 Thomas Alva Edison
Patent Awards (for the patent with the most business impact) from the R&D
Council of NJ.
Distinguished Alumni Award from IIT Delhi,
Bell Labs Fellow, 1997. Fellow of the IEEE (1991) and Fellow of the
The 1991 Leonard G. Abraham Prize Paper Award for "Design and
Implementation of a High-Speed Transport Protocol," published in IEEE Trans.
on Communications, Nov. 1990.
President of India’s Gold Medal, 1975. Institution
of Engineers (India) Gold Medal, 1975.
Invited to be keynote speaker at several top networking conferences including ACM
ACM Mobisys 2015, ACM Mobicom 2002, IEEE High Speed Switching Conf., 2000, SAINT
2003, COMSWARE 2006, TESTCOM 2006, ICDCS 2006, IWQoS 2006, MASS 2006,
Networking 2007, ACM MobiArch 2007, COMSWARE 2008, WWRF 2009, ISWCS 2009, COMSNETS 2010, and several other conferences.
Served as editor for many premier networking Journals: , IEEE/ACM
Transactions on Networking, 1992-98; the Wireless Networks Journal, 1995-99;
IEEE Transactions on Communications, 1988-92; IEEE Transactions on Computers,
1988-92, Journal of Systems Integration, Journal of High Speed Networks,
1992-94, Computer networks, 2001-present and ACM Journal on Wireless Networks,
1996-present. Guest Editor, JSAC,
September 1989 and Computer Networks and ISDN Systems, April 1990.
Played an active role in organizing major
networking conferences: Program
Committee Member of several premier networking conferences including ACM
SIGCOMM, 1989, 1999, 2000, and ACM MOBICOM, 1995-98 Program Chairman of two major networking conferences: ICNP
'94 and PSTV ‘88.
on peer-review panels at NSF, NASA, & Texas High-Education Coordination
on the IEEE Fellow Committee, 1995-98.
Participated in several NSF workshops on
Delivered distinguished lectures at several major
universities such as Duke, Washington, Georgia Tech, IIT Delhi.
Delivered Bharti Lecture in the Bharti School
of Telecommunication Technology & Management, New Delhi.
Served as a UNDP consultant for setting up an
educational data network called ERNET in India, 87.
Selected Articles and Publications
“Multidestination Protocols for Satellite
Communications,” K. Sabnani, M. Schwartz, IEEE
Transactions on Communications, 33(3),
232 – 240 (1985).
” A Protocol Test Generation Procedure,” K. Sabnani, A. Dahbura, Computer Networks
& ISDN Systems, 15(4), 285 – 297 (1988).
Algorithmic Technique for Protocol Verification,” K Sabnani, P Wolper, A Lapone, IEEE Transactions on Communications, 36(8), 924 – 931 (1988).
“A High Speed Transport Protocol for Datagram/Virtual
Circuit Networks,” K Sabnani, AN Netravali - ACM SIGCOMM (1989).
Verification of Communication Protocols,” NF
Maxemchuk, K Sabnani, Distributed Computing (Historical Archive,)
3(3), 118 – 129 (1989).
and Implementation of a High-speed Transport Protocol,” A.N.
Netravali, W.D. Roome, K. Sabnani,
IEEE Transactions on Communications, 38(11), 2010 – 2024 (1990).
“AIRMAIL: A Link-Layer Protocol for Wireless Networks,”
E. Ayanoglu, S. Paul, T.F. La Porta, K.K. Sabnani, R.D. Gitlin, ACM/Baltzer
Wireless Networks Journal. 1(1), 47-60
Multicast Transport Protocol (RMTP),” S. Paul, K.
Sabnani, J.C.H. Lin, S.
Bhattacharyya, IEEE Journal on Selected Areas in communications, 15(3), 407 – 421 (1997).
“Pigeon - A Wireless Two-Way Messaging System,” T.Y.C.
Woo, T.F. La Porta, K. Sabnani, IEEE Journal on Selected Areas in
Communications ,15( 8),
Observations on Multicast Congestion Control in the Internet,” S.J.
Golestani, K.K. Sabnani, IEEE
“The Softrouter Architecture,” T. V. Lakshman, N.
Nandgopal, R. Ramjee, K. Sabnani, T. Woo, ACM
“Multi-Protocol Home Location Register and method of
use,” US Patent #7,522,632. Winner
of the 2009 Edison Patent Award.