Leveraging Innovative Transport Layer Services for Improved Application Performance
Abstract
We investigate three issues related to the transport layer, and address these issues using the innovative transport layer services offered by the Stream Control Transmission Protocol (SCTP) [RFC4960]. In the first issue, we explore the benefits from SCTP's multistreaming service for HTTP-based applications. The current web transport, TCP, offers a sequential bytestream, and in-order data delivery within the bytestream. Transferring independent web objects over a single TCP connection results in head-of-line (HOL) blocking, and worsens web response times. On the contrary, transferring these objects over different SCTP streams eliminates inter-object HOL blocking. We propose a design for HTTP over SCTP streams, and implement this design in the open source Apache web server and Firefox browser. Using emulation, we show that persistent and pipelined HTTP 1.1 transfers over a single multistreamed SCTP association improves web response times when compared to similar transfers over a single TCP connection. The difference in TCP vs. SCTP response times increases and is more visually perceivable in high latency and lossy browsing condition, as found in the developing world. The current workaround to improve an end user's perceived WWW performance is to download an HTTP transfer over multiple TCP connections. While we expect multiple TCP connections to improve HTTP throughput, emulation results show that the competing and bursty nature of multiple TCP senders degrade HTTP performance especially in end-to-end paths with low bandwidth last hops. In such browsing conditions, a single multistreamed SCTP association not only eliminates HOL blocking, but also boosts throughput compared to multiple TCP connections.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2009
- Accession Number
- ADA604062
Entities
People
- Preethi Natarajan
Organizations
- University of Delaware