Modeling the Performance of HTTP Over Several Transport Protocols
John Heidemann, Katia Obraczka, and Joe TouchUSC/Information Sciences Institute
Abstract
This paper considers the interaction of HTTP with several transport protocols, including TCP, Transaction TCP, a UDP-based request-response protocol, and HTTP with persistent TCP connections. We present an analytic model for each of these protocols and use that model to evaluate network overhead carrying HTTP traffic across a variety of network characteristics. This model includes a analysis of the transient affects of TCP slow-start. We validate this model by comparing it to network packet traces measured with two protocols (HTTP and persistent HTTP) over local and wide-area networks. We show that the model is accurate within 5% of measured performance for wide-area networks, but can underestimate latency when the bandwidth is high and delay is low. We use the model to compare the connection-setup costs of these protocols, bounding the possible performance improvement. We evaluate these costs for a range of network characteristics, finding that setup optimizations are relatively unimportant for current modem, ISDN, and LAN users but can provide moderate to substantial performance improvement over high-speed WANs. We also use the model to predict performance over future network characteristics.Availability
This paper is available in several formats: abstract web page with pointers and cites, gzip'ed postscript, PDF, paper copies can be obtained by mail to the authors. Copyright terms for this paper appear below.
Reference
- Heidemann96a
- John Heidemann, Katia Obraczka, and Joe Touch. Modeling the Performance of HTTP Over Several Transport Protocols. To appear, IEEE/ACM Transactions on Networking 5(5), October 1997. November, 1996. <http://www.isi.edu/~johnh/PAPERS/Heidemann96a.html>.
@unpublished{Heidemann96a,
author = "John Heidemann and Katia Obraczka and Joe Touch",
title = "Modeling the Performance of {HTTP} Over Several
Transport Protocols",
note = "To appear, IEEE/ACM Transactions on Networking
5(5), October 1997",
seealso = "Heidemann97b",
year = "1996",
month = "November",
keywords = "http performance, p-http, t/tcp, ardp",
copyrightholder = "{IEEE}",
url = "http://www.isi.edu/~johnh/PAPERS/Heidemann96a.html",
psurl = "http://www.isi.edu/~johnh/PAPERS/Heidemann96a.ps.gz",
pdfurl = "http://www.isi.edu/~johnh/PAPERS/Heidemann96a.pdf",
organization = "USC/Information Sciences Institute",
}