An Argument for Increasing TCP's Initial Congestion Window

被引:129
作者
Dukkipati, Nandita [1 ]
Refice, Tiziana [1 ]
Cheng, Yuchung [1 ]
Chu, Jerry [1 ]
Herbert, Tom [1 ]
Agarwal, Amit [1 ]
Jain, Arvind [1 ]
Sutin, Natalia [1 ]
机构
[1] Google Inc, Mountain View, CA USA
关键词
Measurement; Experimentation; Performance; TCP; Congestion Control; Web Latency; Internet Measurements;
D O I
10.1145/1823844.1823848
中图分类号
TP [自动化技术、计算机技术];
学科分类号
0812 ;
摘要
TCP flows start with an initial congestion window of at most four segments or approximately 4KB of data. Because most Web transactions are short-lived, the initial congestion window is a critical TCP parameter in determining how quickly flows can finish. While the global network access speeds increased dramatically on average in the past decade, the standard value of TCP's initial congestion window has remained unchanged. In this paper, we propose to increase TCP's initial congestion window to at least ten segments (about 15KB). Through large-scale Internet experiments, we quantify the latency benefits and costs of using a larger window, as functions of network bandwidth, round-trip time (RTT), bandwidth-delay product (BDP), and nature of applications. We show that the average latency of HTTP responses improved by approximately 10% with the largest benefits being demonstrated in high RTT and BDP networks. The latency of low bandwidth networks also improved by a significant amount in our experiments. The average retransmission rate increased by a modest 0.5%, with most of the increase coming from applications that effectively circumvent TCP's slow start algorithm by using multiple concurrent connections. Based on the results from our experiments, we believe the initial congestion window should be at least ten segments and the same be investigated for standardization by the IETF.
引用
收藏
页码:26 / 33
页数:8
相关论文
共 16 条
[1]  
*AK, 2000, INT BOTTL
[2]  
*AK, 2009, STAT INT
[3]  
Allman M., 2009, RFC 5681
[4]  
[Anonymous], 2009, SPDY: An experimental protocol for a faster web
[5]  
[Anonymous], 2002, RFC 3390
[6]  
Belshe M., 2010, A client-side argument for changing tcp slow start
[7]  
BENKO P, 2004, LARGE SCALE PASSIVE
[8]  
CARDWELL N, 2000, P IEEE INF
[9]  
DUKKIPATI N, 2010, ARGUMENT INCREASING
[10]  
FLOYD S, 1999, IEEE ACM T NETWORKIN