General-purpose Transport Protocol Research Articles

The packet number space debate in multipath QUIC

With a standardization process that attracted much interest, QUIC can been seen as the next general-purpose transport protocol. Still, it does not provide true multipath support yet, missing some use cases that Multipath TCP addresses. To fill that gap, the IETF recently adopted a Multipath proposal merging several proposed designs. While it focuses on its core components, there still remains one major design issue: the amount of packet number spaces that should be used. This paper provides experimental results with two different Multipath QUIC implementations based on NS3 simulations to understand the impact of using one packet number space per path or a single packet number space for the whole connection. Our results show that using one packet number space per path makes Multipath QUIC more resilient to the receiver's heuristics to acknowledge packets and detect duplicates.

Performance Analysis of SCTP for Multiple Parallel Streams

SCTP is a connection oriented general purpose transport protocol and applications presented in the transport layer for concept of streams. Different streams provide multiple end to end connections that enables independent send and receiver buffer at two end points. In this paper we performed performance measurement for simultaneous parallel streams. Performance of SCTP is closely examined for two parallel streams and considerable improvement of bandwidth utilization observed as compared to single stream

Enabling PVM to exploit the SCTP protocol

Recently, a new general purpose transport protocol, called SCTP, has been standardized by the IETF to be used in IP based applications. The features of SCTP, compared with TCP, better support the communication requirements of parallel applications and have motivated the development of SCTP-PVM, a PVM extension, that uses SCTP for direct communications among tasks. Using the LK-SCTP open source kernel module implementation of SCTP, we have compared the performances of SCTP-PVM with the standard version of PVM that, through the PvmRouteDirect directive, uses TCP. Due to the vast difference in the maturity level of both protocols where TCP, unlike SCTP, is able to offload checksum calculations and transport segmentations in hardware, in the tests performed, we have disabled the TCP hardware transport segmentations and we have analyzed the behaviour of SCTP-PVM both with the checksum enabled and disabled. SCTP-PVM, with the checksum disabled, resulted better as the messages exchanged among tasks increase. In addition, thanks to the SCTP multi-streaming feature, SCTP-PVM achieved higher throughput in error prone networks. On the other hand, due to the high-protocol processing cost of the checksum enabled, SCTP-PVM resulted slower. Finally, the SCTP-PVM extension has been designed to easily enable existing PVM applications to use the SCTP protocol features.

On SCTP multi-homing performance

The Stream Control Transmission Protocol (SCTP) is a general purpose transport protocol featuring multi-homing support, message oriented and more flexible data delivery mechanisms than TCP, and an increased protection against well-known attacks. Originally developed for the transport of Signaling System No. 7 messages, e.g. MTP level 3 user primitives, over IP networks, SCTP has evolved to a general purpose transport protocol with a wide field of applications. With respect to multi-homing, the current SCTP standard uses this feature for network level redundancy only. Therefore we propose and evaluate in this contribution mechanisms for the application-specific optimisation of the SCTP protocol behaviour with respect to its multi-homing capabilities. To satisfy the extremely strict performance requirements for signalling transport, efficient load sharing among all active links is also highly desirable in SCTP scenarios. To this end, we propose a novel, improved load sharing algorithm for SCTP with path based selective acknowledgements which avoids some of the drawbacks of the existing algorithms and achieves an increase in throughput. Results of a comparative simulation study are presented to demonstrate the benefits of our algorithm.

Secure SCTP – A Versatile Secure Transport Protocol

The Stream Control Transmission Protocol (SCTP) is a new general purpose transport protocol defined by the IETF. Originally intended for the transport of voice signaling data (SS7) over IP networks, SCTP together with newly defined extensions is increasingly considered for other application scenarios as well. These require strong security solutions to authenticate the communication partners and protect sensitive data with respect to integrity and confidentiality. Proposals have been issued on how to protect SCTP transport by using standard security protocols such as TLS and IPsec. However, these solutions introduce limitations or inefficiencies und thus may not be able to fully exploit the capabilities of SCTP. Therefore, we propose a security extension to SCTP named Secure SCTP (S-SCTP) to solve these issues in an efficient and user-friendly way.

Gaining efficiency in transport services by appropriate design and implementation choices

End-to-end transport protocols continue to be an active area of research and development involving (1) design and implementation of special-purpose protocols, and (2) reexamination of the design and implementation of general-purpose protocols. This work is motivated by the perceived low bandwidth and high delay, CPU, memory, and other costs of many current general-purpose transport protocol designs and implementations. This paper examines transport protocol mechanisms and implementation issues and argues that general-purpose transport protocols can be effective in a wide range of distributed applications because (1) many of the mechanisms used in the special-purpose protocols can also be used in general-purpose protocol designs and implementations, (2) special-purpose designs have hidden costs, and (3) very special operating system environments, overall system loads, application response times, and interaction patterns are required before general-purpose protocols are the main system performance bottlenecks.