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Web Dispatcher

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  • SAP Web Dispatcher 6.40 for SAP Web AS Java

    Jochen RundholzNW RIG APA

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 2

    RIG Know How Conf Calls

    Please: All participants will be muted

    Questions in the Q&A section at the end Important issues via WebEx chat

    Mute your phone Use the Mute button where available or Key in *6* to mute and *6* to unmute in case you want to ask a question

    Give feedback for further improvements

  • Introduction

    Installation

    Administration

  • Introduction Web Applications and Web ServersIntroduction Load Balancer

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 5

    Requirements of Business Web Applications

    Scalability and performance Scale out via additional applicaton server Loadbalancer

    necessary Dynamic content leads to low fraction of cachable content

    Transcational Session persistance necessary

    Security Protection of application servers (DMZ, revers proxys, fire walls, ...) Authentication Encryption

    Stability High availibility is necessary

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 6

    "Old" SAP Application Server Architecture

    SAPGUI

    RFCClient/Server

    Dispatcher

    Gate-way

    RDBMS

    WorkProcesses

    D

    I

    A

    G

    R

    F

    C

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 7

    SAP Web Application Server 6.40

    RFCClient/ServerBrowser SAPGUI

    D

    I

    A

    G

    ICM

    J2EEDispatcher

    J2EEServer

    Processes

    Dispatcher

    Gate-way

    RDBMS

    WorkProcesses

    R

    F

    C

    H

    T

    T

    P

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 8

    System Communication

    ICM

    MSMPI

    JCo

    HTTP

    SAP GUI

    ABAP

    Central ServicesEnqueue-ServerEnqueue-Server

    Message-ServerMessage-Server

    SDM

    Server Server. . .

    Java-Dispatcher

    JAVA

    WP WP. . .

    ABAP-Dispatcher

    Internet

    Web Browser/Web Server

  • Introduction Web Applications and Web ServersIntroduction Load Balancer

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 10

    Load Balancing Design Criteria

    Load balancing mechanism (client or server side)

    End-to-end SSL or SSL termination in load balancer. In-depth vs. end-to-end security, need to inspect traffic Persistence mechanism (session ID or IP address) Client certificate authentication

    Cost of device

    Performance

    Robustness and high availability

    Ease of configuration and operation (TCO)

    Integration into existing infrastructure and security policy

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 11

    Facts and Features of SAP Web Dispatcher

    Usability Single point of access only one URL for user, only one official IP

    address Load balancing and configuration via message server

    Scalability and performance Software solution, not a hardware solution

    Transactional Session persistence via cookie (HTTP) or IP address (HTTPS)

    Security Protection of application servers (DMZ, reverse proxy, fire walls, ...) Authentication SSL Termination, end to end SSL, re-encryption Simple request filtering

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 12

    Hardware Load Balancer vs. SAP Web Dispatcher

    Pro Additional features Re-use existing infrastructure Unified Web infrastructure for all Web systems (SAP and non-SAP)

    Contra Cost Less integrated with SAP Web AS Configuration, operation, maintenance requires special expertise

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 13

    Load Balancing Mechanisms (Redirection & DNS)

    Redirections Simple Bad user experience and maintenance

    DNS based methods Perhaps OK for intranet OK for global load balancing Generally not OK for server load balancing

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 14

    Drawbacks of Redirection

    Many official external DNS names and IP addresses

    Confusing for the user, bookmarking destroys load balancing

    With SSL Server certificate must match URL Every application server needs separate server certificate High administrative overhead Expensive

    May lead to unnecessary user authentication dialogs

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 15

    Load Balancing Mechanisms (Server Side)

    Load balancing device Transparent for client Always the same URL One official IP address for all application servers One server certificate for all servers Technically challenging Usually preferable

    LoadBalancer

    ApplicationServer

    ApplicationServer

    ApplicationServer

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 16

    Web Dispatcher

    SAPWeb

    Dispatcher

    MessageServer

    CentralInstance

    DialogInstance

    DialogInstance

    RDBMS

    http://web.acme.com

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 17

    Web Dispatcher For Multiple SAP Web AS

    Multiple Web Dispatchers on different TCP ports

    Not recommended J2EE session cookies

    overwrite each other. SSL to port other than 443

    often not possible

    https://web

    SAP WebDispatcher

    CorporateNetworkSAP Web

    AS

    SAP WebDispatcher

    CorporateNetworkSAP Web

    AS

    443

    444

    https://web:444IP

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 18

    Web Dispatcher For Multiple SAP Web AS

    Multiple Web Dispatchers on different (virtual) IP addresses

    Recommended

    https://web1

    SAP WebDispatcher

    CorporateNetworkSAP Web

    AS

    SAP WebDispatcher

    CorporateNetworkSAP Web

    AS

    443

    443

    IP1

    IP2

    https://web2

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 19

    Integration Into Web Server / Reverse Proxy

    SAP WebAS

    Web Server

    Reverse ProxyModule

    F

    i

    r

    e

    w

    a

    l

    l

    Static WebPages

    Internet

    443

    F

    i

    r

    e

    w

    a

    l

    l

    /sap*

    other

    Integrate SAP Web AS services into Web site

    Optional Web Dispatcher for Scaling

    Forward requests for/sap* to SAP Web AS

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 20

    Network Security

    Optional high security network with internal firewall

    Internal ServerNetwork

    High SecurityNetwork

    Secure ServerNetwork (DMZ)

    Internet

    Database

    DB

    DB

    ApplicationProxy

    SAP WebApplication

    Server

    R/3, FI, HRetc.

    Web Servers ApplicationsProtected

    Applications

    F

    i

    r

    e

    w

    a

    l

    l

    F

    i

    r

    e

    w

    a

    l

    l

    F

    i

    r

    e

    w

    a

    l

    l

    F

    i

    r

    e

    w

    a

    l

    l

    Intern.Firew.

    Internal Server

    Network

    Secure Serv.Network(DMZ)

    Internet

    DB

    ApplicationProxy

    SAP WebApplication

    Server

    Web Servers Applications

    F

    i

    r

    e

    w

    a

    l

    l

    AccessRouter

    &Firewall

    F

    i

    r

    e

    w

    a

    l

    l

    Firewall

  • Introduction

    Installation

    Administration

  • SizingInstallationHigh Availability

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 23

    CPU Sizing

    No measurements available yet Main factor is the usage of SSL

    No SSL at allTermination of SSLTermination and re-encryption of SSL

    Termination of SSL is expensive Re-encryption is not very expensive since only the handshake is

    expensive and the handshake between server and SAP Web Dispatcher has to be done only every couple of hours

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 24

    Memory sizing

    Memory usage for internal tables Server tables

    Holding information about connected serversUsually very small (90 kB default, few MB for very large system)

    Connection tablesHolding information about the open connectionsconcurrent_conn = (users * req_per_dialog_step *conn_keepalive_sec)/

    (thinktime_per_diastep_sec)mpi/total_size_mb = (concurrent_conn * mpi_buffer_size)/(1024* 1024)z Default: mpi_buffer_size = 32kBz Default: mpi/total_size_mb = 500

    End to End SSL table1.8 MB for 10.000 entries

  • SizingInstallationHigh Availability

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 26

    Installating the SAP Web Dispatcher

    Media for the web dispatcher is provided with the J2EE kernel:

    C:\usr\sap\\\exe\sapwebdisp.exeicmadmin.SAR

    To install and setup the SAP Web Dispatcher:

    1. Download kernel files from SAP service market place

    2. Extract kernel using sapcar -xvf3. Copy the sapwebdisp.exe and icmadmin.SAR files to a directory

    on what is to be the Web Dispatcher host.

    4. Use sapcar xvf to extract the icmadmin.SAR file into that directory.

    5. Execute sapwebdisp bootstrap to generate an initial profile for the Web Dispatcher

    6. Start the web dispatcher with sapwebdisp pf=sapwebdisp.pfl

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 27

    Download from service.sap.com/download

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 28

    Unpack kernel

    These are only the minimum files sometimes additional files might be used/helpful

  • SAP AG 2004, SAP Web Dispatcher /Jochen Rundholz / 29

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