IETF Internet Drafts (work in progress)

Low Extra Delay Background Transport (LEDBAT) [Paper]
Stanislav Shalunov, G. Hazel, Janardhan Iyengar, Mirja Kuehlewind
IETF Internet-draft, LEDBAT working group


Load Sharing for the Stream Control Transmission Protocol [Paper]
Martin Becke, Thomas Dreibholz, Janardhan Iyengar, Preethi Natarajan, Michael Tuexen
IETF Internet-draft, TSV working group


Non-Renegable Selective Acknowledgments (NR-SACKs) for SCTP [Paper]
Preethi Natarajan, Nasif Ekiz, Ertugrul Yilmaz, Paul Amer, Randall Stewart, Janardhan Iyengar
IETF Internet-draft, TSV working group


2012

Fitting Square Pegs Through Round Pipes: Unordered Delivery Wire-Compatible with TCP and TLS [Paper : Slides]
Michael Nowlan, Nabin Tiwari, Janardhan Iyengar, Syed Obaid Amin, Bryan Ford
USENIX NSDI 2012, April, 2012

(longer draft at: http://arxiv.org/abs/1103.0463)


2011

Dynamic Window Coupling for Multipath Congestion Control [Paper]
Sofiane Hassayoun, David Ros, Janardhan Iyengar
IEEE ICNP 2011, October 2011


TCP Behavior in Sub-Packet Regimes (Extended Abstract) [Paper]
Jay Chen, Janardhan Iyengar, Lakshminarayanan Subramanian, Bryan Ford
SIGMETRICS 2011 Poster Session, June 2011


RFC 6182: Architectural Guidelines for Multipath TCP Development [Paper]
Alan Ford, Costin Raiciu, Mark Handley, Sebastian Barre, Janardhan Iyengar
Internet RFCs, ISSN: 2070-1721, RFC6182, March 2011


2010

Minion—an All-Terrain Packet Packhorse to Jump-Start Stalled Internet Transports [Paper : Slides]
Janardhan Iyengar, Bryan Ford, Dishant Ailawadi, Syed Obaid Amin, Michael Nowlan, Nabin Tiwari, Jeffrey Wise
PFLDNet 2010, November 2010


Employing Transport Layer Multi-railing In Cluster Networks [Paper]
Brad Penoff, Humaira Kamal, Alan Wagner, Mike Tsai, Karol Mroz, Janardhan Iyengar
Journal of Parallel and Distributed Computing (JPDC), March 2010

In this work, we explore the applicability of CMT in the transport layer of the network stack to high-performance computing environments. We develop SCTP-based MPI (Message Passing Interface) middleware for MPICH2 and OpenMPI, and evaluate the reliability and communication performance of the system. Using OpenMPI with support for message striping over multiple paths at the middleware level, we compare the differences in supporting multi-railing in the middleware versus at the transport layer.


RFC 5690: Adding Acknowledgement Congestion Control to TCP [Paper]
Sally Floyd, Andres Arcia, David Ros, Janardhan Iyengar
Internet RFCs, ISSN: 2070-1721, RFC5690, February 2010

This document adds an optional congestion control mechanism for acknowledgement traffic (ACKs) to TCP. The document specifies an end-to-end acknowledgement congestion control mechanism for TCP that uses participation from both TCP hosts, the TCP data sender and the TCP data receiver.


2009

Flow Splitting with Fate Sharing in a Next Generation Transport Services Architecture [Paper : Abstract]
Janardhan Iyengar, Bryan Ford
Under Submission

The challenges of optimizing end-to-end performance over diverse Internet paths has driven widespread adoption of in-path optimizers, which can destructively interfere with TCP’s end-to-end semantics and with each other, and are incompatible with end-to-end IPsec. We identify the architectural cause of these conflicts and resolve them in Tng, an experimental next-generation transport services architecture, by factoring congestion control from end-to-end semantic functions.


Efficient Cross-Layer Negotiation [Paper]
Bryan Ford, Janardhan Iyengar
ACM HotNets-VIII (Hot Topics in Networks), New York, New York, October 2009

Internet evolution often depends on either inserting new protocol layers or upgrading existing layers to new protocols, but both of these evolutionary paths are obstructed by the difficulty and inefficiency of determining which protocols a pair of hosts mutually support and prefer. We propose a novel cross-layer Negotiation Protocol that sets up a complete stack of connection-oriented protocols at once, concurrently performing handshaking for multiple layers and choosing among alternative protocols for each layer in as few round trips as possible, often just one.


2008

Breaking Up The Transport Logjam [Paper : Abstract : Slides]
Bryan Ford, Janardhan Iyengar
ACM HotNets-VII (Hot Topics in Networks), Calgary, Canada, October 2008

Current Internet transports conflate transport semantics with endpoint addressing and flow regulation, creating roadblocks to Internet evolution that we propose to address with a new layering model.


Non-Renegable Selective Acknowledgments (NR-SACKs) for SCTP [Paper : Abstract]
Preethi Natarajan, Nasif Ekiz, Ertugrul Yilmaz, Paul Amer, Janardhan Iyengar, Randall Stewart
IEEE International Conference on Network Protocols (ICNP), October 2008

In both TCP and SCTP, selectively acked (SACKed) out-of-order data is implicitly renegable; that is, the receiver can later discard SACKed data. The possibility of reneging forces the transport sender to maintain copies of SACKed data in its send buffer until that data is cumulatively acked. In this paper, we investigate the situation where all out-of- order data is non-renegable, such as when the data has been delivered to the application, or when the receiver simply never reneges.


Concurrent Multipath Transfer using SCTP Multihoming: Introducing Potentially-failed Destination State [Paper : Abstract]
Preethi Natarajan, Nasif Ekiz, Janardhan Iyengar, Paul Amer, Randall Stewart
IFIP Networking, May 2008

Previously, we identified the failure-induced receive buffer blocking problem in Concurrent Multipath Transfer using SCTP multihoming (CMT), and proposed CMT with a Potentially-failed destination state (CMT-PF) to alleviate the same. Using ns-2 simulations, we showed CMT-PF's throughput improvement over CMT during permanent and short-term failures.


2007

Using CMT in SCTP-based MPI to Exploit Multiple Interfaces in Cluster Nodes [Paper : Abstract]
Brad Penoff, Mike Tsai, Janardhan Iyengar, Alan Wagner
Euro PVM/MPI, Paris, France, October 2007

Many existing clusters use inexpensive Gigabit Ethernet and often have multiple interfaces cards to improve bandwidth and enhance fault tolerance. We investigate the use of Concurrent Multipath Transfer (CMT), an extension to the Stream Control Transmission Protocol (SCTP), to take advantage of multiple network interfaces for use with MPI programs.


Performance Implications of a Bounded Receive Buffer In Concurrent Multipath Transfer [Paper : Abstract]
Janardhan Iyengar, Paul Amer, Randall Stewart
Computer Communications, vol 30/4, pp 818-829, February 2007

We study the performance of Concurrent Multipath Transfer using SCTP multihoming (CMT) in the presence of a bounded receive buffer (rbuf). We demonstrate using simulation that if two paths are used for CMT, the lower quality (i.e., higher loss rate) path degrades overall throughput of an rbuf-constrained CMT association by blocking the rbuf.


2006

Concurrent Multipath Transfer Using SCTP Multihoming Over Independent End-to-End Paths [Paper : Abstract]
Janardhan Iyengar, Paul Amer, Randall Stewart
IEEE/ACM Transactions on Networking, 14(5), October 2006

Concurrent multipath transfer (CMT) uses the Stream Control Transmission Protocol's (SCTP) multihoming feature to distribute data across multiple end-to-end paths in a multihomed SCTP association. We identify three negative side-effects of reordering introduced by CMT that must be managed before efficient parallel transfer can be achieved: (1) unnecessary fast retransmissions by a sender; (2) overly conservative congestion window (cwnd) growth at a sender; and (3) increased ack traffic due to fewer delayed acks by a receiver.


Concurrent Multipath Transfer Using Transport Layer Multihoming: Performance Under Network Failures [Paper : Abstract]
Preethi Natarajan, Janardhan Iyengar, Paul Amer, Randall Stewart
MILCOM 2006, Washington D. C., October 2006

Recent research on Concurrent Multipath Transfer using SCTP multihoming (CMT) proposed various retransmission policies to minimize the negative impacts of receiver buffer (rbuf) blocking that occur during congestion. Here we investigate CMT's throughput degradation caused by rbuf blocking during complete and/or short-term network failures.


SCTP: An Innovative Transport Layer Protocol For The Web [Paper : Abstract]
Preethi Natarajan, Janardhan Iyengar, Paul Amer, Randall Stewart
WWW 2006, Edinburgh, Scotland, May 2006

We propose using the Stream Control Transmission Protocol (SCTP), a recent IETF transport layer protocol, for reliable web transport. Although TCP has traditionally been used, we argue that SCTP better matches the needs of HTTP-based network applications.


End-to-End Concurrent Multipath Transfer Using Transport Layer Multihoming [Paper : Abstract : Slides]
Janardhan Iyengar
PhD Dissertation, Computer Science Dept., University of Delaware, April 2006

Transport layer multihoming binds a single transport layer association to multiple net- work addresses at each endpoint, thus allowing the two end hosts to communicate over multiple network paths. This dissertation investigates end-to-end Concurrent Multipath Transfer (CMT) using transport layer multihoming for increased application throughput. CMT is the simultaneous transfer of new data from a source host to a destination host via two or more end-to-end paths.


2005

Receive Buffer Blocking In Concurrent Multipath Transfer [Paper]
Janardhan Iyengar, Paul Amer, Randall Stewart
Globecom 2005, November 2005

Previously, we studied the performance of Concurrent Multipath Transfer using SCTP Multihoming (CMT) under the assumption of an infinite receive buffer (rbuf). Here, we study CMT performance when a sender is constrained by the rbuf.


2004

Retransmission Policies For Concurrent Multipath Transfer Using SCTP Multihoming [Paper]
Janardhan Iyengar, Paul Amer, Randall Stewart
ICON 2004, Singapore, November 2004

Concurrent Multipath Transfer (CMT) uses the Stream Control Transmission Protocol's (SCTP's) multihoming feature to distribute data across multiple end-to-end paths in a multihomed SCTP association. We propose five retransmission policies for CMT.


On the Prevalence and Evaluation of Recent TCP Enhancements [Paper]
Sourabh Ladha, Paul Amer, Armando Caro, Janardhan Iyengar
Globecom 2004, November 2004

In recent years several enhancements to TCP congestion control and loss recovery mechanisms have been proposed and accepted as Internet standards. While each proposal has been accompanied with related research, a number of questions remain to be answered both in the research and the implementer community: (i) What is the current deployment status of these TCP enhancements in the Internet, (ii) What is the effect of TCP enhancements on web based transfers, and (iii) How do bulk data transfers benefit from the cumulative addition of these TCP enhancements. In this paper, we attempt to answer these questions.


Concurrent Multipath Transfer Using SCTP Multihoming [Paper]
Janardhan Iyengar, Keyur Shah, Paul Amer, Randall Stewart
SPECTS 2004, San Jose, July 2004

We propose CMT - Concurrent Multipath Transfer using the Stream Control Transmission Protocol (SCTP). CMT uses SCTP's multihoming feature to simultaneously transfer new data across multiple end-to-end paths to the receiver.


2003

SCTP: A Proposed Standard for Robust Internet Data Transport [Paper]
Armando Caro, Janardhan Iyengar, Paul Amer, Sourabh Ladha, Gerard Heinz, Keyur Shah
IEEE Computer, 36(11):56-63, November 2003

The Stream Control Transmission Protocol is a new standard for general-purpose transport proposed by the Internet Engineering Task Force. SCTP addresses application and security gaps left open by its predecessors, TCP and UDP.


Making SCTP More Robust to Changeover [Paper]
Janardhan Iyengar, Armando Caro, Paul Amer, Gerard Heinz, Randall Stewart
SPECTS 2003, Montreal, Canada, July 2003

We present a problem in the current SCTP (RFC2960) specification that results in unnecessary retransmissions and TCP-unfriendly growth of the sender's congestion window during certain changeover conditions. We first illustrate the problem using an example scenario. To gain insight into the ambient conditions under which cwnd overgrowth can be observed, we present an analytical model of this problem.


SCTP Multistreaming: Preferential Treatment Among Streams [Paper]
Sunil Samtani, Janardhan Iyengar, Mariusz Fecko
MILCOM 2003, Boston, Massachussets, October 2003

FCS networks are presented with a new transport layer mechanism that, for transmitting multimedia, is markedly superior to transmission over UDP or TCP. SCTP's multistreaming provides an aggregation mechanism for transferring different objects belonging to the same logical application session; however, sharing the congestion state among the streams precludes efficient stream prioritization. We design an SCTP mechanism to provide the application with the service of being able to mark data such that different parts of a transfer (different streams) could be requested to receive preferential treatment from the network.


Improving File Transfer in FCS Networks [Paper]
Sourabh Ladha, Armando Caro, Paul Amer, Janardhan Iyengar
MILCOM 2003, Boston, Massachussets, July 2003

We compare the performance of two transport protocols, SCTP and the New-Reno variant of TCP, for file transfers in two FCS networking scenarios. We argue why SCTP is better suited for file transfers in a network prone to resource failures.


Retransmission Policies with Transport Layer Multihoming [Paper]
Armando Caro, Paul Amer, Janardhan Iyengar, Randall Stewart
ICON 2003, Sydney, Australia, September 2003

We evaluate several retransmission policies for transport protocols that support multihoming, such as SCTP. We find that schemes that attempt to improve the chance of success by retransmitting to an alternate peer IP address often degrade performance


Posters

Design Ideas on Preferential Treatment Among Streams [Paper]
Janardhan Iyengar, Sunil Samtani
Army Science Conference, Orlando, Florida, December 2002

Poster with abstract in ASC proceedings.


Using SCTP Multihoming for Fault Tolerance and Load Balancing [Paper : Abstract]
Armando Caro, Janardhan Iyengar, Paul Amer, Gerard Heinz, Randall Stewart
SIGCOMM 2002, Pittsburg, Pennsylvania, August 2002

Poster with abstract in Computer Communication Review 32(3):23, July 2002.


Unpublished Technical Reports

SCTP and TCP Variants: Congestion Control Under Multiple Losses [Paper]
Armando Caro, Keyur Shah, Janardhan Iyengar, Paul Amer, Randall Stewart
Tech Report TR2003-04, CIS Department, University of Delaware, February 2003

We characterize an inefficiency in the current specification of SCTP's congestion control, which degrades performance (more than necessary to be TCP-friendly when there are multiple packet losses in a single window. We present an SCTP variant, called New-Reno SCTP, which introduces three modifications.


Dealing With Short TCP Flows: A Survey of Mice in Elephant Shoes [Paper]
Janardhan Iyengar, Armando Caro, Paul Amer
Tech Report, CIS Department, University of Delaware, August 2003

Short web transfers that dominate the Internet suffer from TCP's inadequate provisioning for short flows. This paper surveys ten proposals that attempt to solve one or more of the problems of short flows, and suggests general criteria to evaluate them.