Network Load (Release 4.0)Created on: April 1998R/3 Release: 4.0Table of ContentsIntroductionEstimating Network TrafficNetwork Traffic in Different ReleasesComparing Benchmark Results of Releases 3.0 and 4.0Calculating the Line Capacity for the Network TrafficPreconditionsExampleIllustration of the Network Load for 4.0IntroductionSAP provides this documentation for its customers, partners and all parties interested in initial network sizing. As the sizing of networks depends on the overall system sizing, the SAP hardware partners and their respective competence centers bear the responsibility. Estimating Network TrafficThis paper contains research results on data traffic in the R/3 System. First, we briefly describe the communication between the presentation server and the application server in a three-tier model. Then we will introduce a formula to calculate the line capacity that is needed for the network traffic. This formula relies on the results of standard benchmarks such as Sales and Distribution (SD), Financials (FI) and Materials Management (MM). Note that the benchmarks only measure GUI traffic and exclude local printing, graphics or the up-/download of office applications.In general, R/3 is implemented through a three-tier client-server model. Three-tier R/3 installations use various network components for the communication between presentation and application server on one hand and application and database server on the other. Two-tier R/3 systems require network communication between the presentation frontend and the central instance.In the three-tier model, data is transferred from the presentation server to the application server via dialog steps (screen changes). During this process, between 1,5 and 2,0 KBytes are transferred on average. The line capacity between the different layers depends on numerous factors and should be at least 10 Mbit/sec. For configurations of medium or large-scale scale, SAP highly recommends a high speed network (e.g. FDDI - 100 Mbit/s). Network Traffic in Different Releases Comparing various releases of the SAP GUI (2.0, 2.1, 2.2, 3.0, and 4.0), we find two factors that influence network traffic: 1. The amount of data transferred between the application and presentation server increases. 2. The compression logic for the GUI has improved. Therefore the network requirements for Release 3.0 are basically the same as for 2.1 and 2.2. Customers do not need to change or upgrade their existing LAN or WAN networks to use R/3 Release 3.0.For Release 4.0, the number of transferred bytes per dialog step is increased slighty. We obtained this data mainly by measuring the frame size in the LAN. During every dialog step, the system sends four packages of an average of approximately 1,700 Byte. In the following figure you can see the changes in network traffic over the last releases. Comparing Benchmark Results of Releases 3.0 and 4.0 In SD, the screens have been completely redesigned. For measurements, we increased the screen size by 10% in order to avoid further dialog steps. Also, new pull-down menus added between 300 and 400 Bytes to the results.FI has increased its data throughput by 13% mainly due to the extended protocol for new functions in 4.0.In MM, the data throughput per screen has not increased significantly, even though the variable Step-Loop dynpros were replaced with the Table Control technique.The increased network traffic you can see in the diagram is mainly due to growing cross-application functions and frontend level integration. Most of the integration options lie on the server side affecting the central server LAN. No additional traffic is generated for the company LAN. Upgrading to Release 4.0 will presumably not require an upgrade of the network.Calculating the Line Capacity for the Network Traffic The following formula can be used to calculate the required line capacity for the network traffic between the presentation and the application server. Preconditions The number of users, the line utilization, the thinktime and the response time are input parameters for the formula. In order to ensure acceptable network response times, line utilization should not be higher than 50% also assuming that only SAP dialogs are running on the network.Definitions:C = Required line capacity measured in bit/secL = Line utilization (0 < L < 1)TThink = Thinktime between two dialog stepsTRes = Response TimeN = Total number of users with thinktime TThink and response time TRes C = 16.000 * N / [L * (TThink + TRes)] bit/sec The formula is based on measurements of the R/3 FI, MM and SD Standard Application Benchmark for Release 4.0.The connection of the presentation frontend to the application server can be established using a Local Area Network (LAN) or a Wide Area Network (WAN). All the different network types such as Ethernet, Token Ring, FDDI, and ATM can be used.We recommend do not to use lines with capacity less than 9,600 bit/sec. Experience shows that working with the theoretical maximum leads to very spiky network traffic and therefore to long response times, because the calculation averages cover only a few users and does not reflect real user behavior.Example1. 15 users, 10 sec thinktime, 2 sec response timeN = 15, L = 0.5C = 16,000 * 15 /[ 0.5 (10 sec + 2 sec)] bit/sec = 40,000 bit/sec => 64,000 bit/sec line 2. 30 users, 30 sec thinktime, 1 sec response timeN = 30, L = 0.5C = 16,000 * 30 /[ 0.5 (30 sec + 1 sec)] bit/sec = 31,000 bit/sec => 64,000 bit/sec line Illustration of the Network Load for 4.0The following figure illustrates the average network load between presentation layer and application layer and between application layer and database layer. SAP TechNet Knowledge Base ArticleTopic: System MonitoringSubtopic: Workload BalanceKeywords: SAP Home Page: http://www.sap.com