BIB-VERSION:: CS-TR-v2.0
ID:: UCB//S2K-92-18 
ENTRY:: February 18, 1994 
TITLE:: A Performance Analysis of TCP/IP and UDP/IP
        Networking Software for the DECstation 5000 
DATE:: 
AUTHOR:: Kay, Jonathan 
AUTHOR:: Pasquale, Joseph   
PAGES:: 21
ABSTRACT:: Modern workstations increasingly rely on distributed
software such as NFS and NIS, yet the speed of networking software
is not improving as rapidly as the workstation and networking hardware,
leading to a network software bottleneck. We present detailed measure-
ments of various components of the TCP/IP and UDP/IP protocol stack on
a DECstation 5000/200 running Ultrix 4.2a. Measurements are by layer
(i.e. socket, transport, IP, data-link) and by function (i.e. checksum
computation, data copying, buffer management, protocol processing, and
operating system interaction), with further breakdowns within each
category. We show that checksum computation and data transfers dominate
component times for a real LAN workload, that using large packet MTUs 
(maximum tranmission units) is very important to achieving high through-
put, and that given the distribution of component times for small
sized messages, it will be difficult to improve latency. TCP and UDP
time breakdowns are shown to be quite similar, suggesting that "light-
weight" transport protocols are not likely to greatly decrease processing time. 
Finally, analytical models for network software processing times are presented. 
RETRIEVAL:: postscript (in all.ps)
END:: UCB//S2K-92-18