Harvard University Oracle Database Administration CSCI E256 Session 7 Oracle Networking

Harvard University Oracle Networks  The function of Oracle Net is to establish and maintain connections between a client application and an Oracle database server.  Oracle Net has many communication layers that enable clients and database servers to share and modify data.

Harvard University TCP/IP  The Transmission Control Protocol/Internet Protocol (TCP/IP) is the de facto standard Ethernet protocol used for client/server conversations over a network.  TCP/IP enables an Oracle application on a client to communicate with remote Oracle databases (if the Oracle database is running on a host system that supports network communication using TCP/IP).

Harvard University Oracle Networks  The communication architecture is based on the Open Systems Interconnection (OSI) model  The OSI model uses a communication stack where information moves from one node to the other, through several layers of code

Harvard University Communications Stack  The concept of distributed processing relies on the ability of computers separated by both design and physical location to communicate and interact with each other.  This is accomplished through a process known as stack communications.  Stack communications can be explained by referencing the Open Systems Interconnection (OSI) model.

Harvard University OSI URL  More Information – for information about the OSI stack

Harvard University OSI Communications Stack

Harvard University Oracle Client/Server Connections

Harvard University Communications Stack  Client Application The OSI layer closest to the user, and is dependent on the functionality requested by the user.  Presentation Ensures that data is represented in a format that the application and session layers can accommodate.  This includes keeping track of syntax and semantics of the data transferred between the client and server.

Harvard University Communications Stack  Session Establishes, manages, and terminates network sessions between the client and server.  This is a virtual pipe that carries data requests and responses.  The session layer manages whether the data traffic can go in both directions at the same time (asynchronous), or in only one direction at a time (synchronous).  Transport Implements the data transport ensuring that the data is transported reliably.

Harvard University Communications Stack  Network Ensures that the data transported is routed through optimal paths, through a series of interconnected sub-networks.  Link Provides reliable transit of data across a physical link.  Physical Defines the electrical, mechanical, and procedural specifications for activating, maintaining and deactivating the physical link between client and server.

Harvard University OSI Stack

Harvard University OSI Layers

Harvard University Oracle Stack

Harvard University Client Application  Oracle client applications provide data presentation and application flow.  The application identifies database operations to send to the server and passes them through to the Oracle Call Interface (OCI).

Harvard University Oracle Call Interface (OCI)  Oracle Call Interface (OCI) code contains all the information required to initiate a SQL dialog between the client and the server.  It defines the calls made to the server – Parse SQL statements for syntax validation – Open a cursor for the SQL statement – Close the cursor

Harvard University Two-Task Common (TTC)  This is Oracle ’ s implementation of the presentation layer.  TTC provides character set and data type conversion between different character sets or formats on the client and server.  It performs conversion only when required  At the time of initial connection, it determines if conversions are required for the two computers to communicate.

Harvard University Oracle Net  Oracle Net provides all the session and transport layer functionality in an Oracle communication stack.  It is responsible for establishing and maintaining the connection between the client application and server, as well as exchanging messages between them.  Oracle Net is also responsible for mapping session functionality into industry-standard protocols.

Harvard University Network Interface (NI)  This layer provides a generic interface for Oracle clients, servers, or external processes to access Oracle Net functions.  The NI layer handles the "break" and "reset" requests for a connection.  NI uses Network Naming (NN) to resolve names to connect descriptors.

Harvard University Network Session (NS)  This layer receives requests from NI, and settles all generic machine-level connectivity issues, such as: the location of the server  NS uses Network Route (NR) to route the network session to the destination and Network Authentication (NA) to negotiate any authentication requirements with the destination.

Harvard University Oracle Protocols  Oracle protocols are Oracle ’ s implementation of the transport layer.  Oracle protocols are responsible for mapping NS functionality to industry-standard protocols used in the client-server connection. protocol.  Oracle protocols include: – TCP/IP – TCP/IP with SSL – SPX

Harvard University Network-Specific Protocols  All Oracle software in the client-server connection process requires an existing network protocol stack to make the machine-level connection between the two machines for the transport layer.  The network protocol is responsible only for getting the data from the client machine to the server machine, at which point the data is passed to the server-side Oracle protocol.

Harvard University Oracle Program Interface (OPI)  Oracle Program Interface (OPI) performs a complementary function to that of the OCI.  It is responsible for responding to each of the possible messages sent by the OCI.  For example, an OCI request to fetch 25 rows would have an OPI response to return the 25 rows once they have been fetched.

Harvard University Bequeath  The Bequeath protocol enables clients that exist on the same machine as the server to retrieve information from the database without using the listener.  The Bequeath protocol internally spawns a dedicated server process for each client application.  Bequeath is used for local connections where an Oracle client application, such as SQL*Plus, communicates with an Oracle server running on the same machine

Harvard University Oracle Network  Oracle Net, Net8(Oracle8) and SQL*Net V2 (Oracle7) are used to connect a client to a server  The client is the application, in either a two- tier or 3-tier architecture  The server is the system where the database is located  Oracle Net and SQL*Net V2 are Oracle tools

Harvard University Oracle Network  The Oracle Net software needs to be installed on both client and and the server, for 2-tier applications.  It is part of the RDBMS installation  3-Tier or web based applications do not need Oracle Net software installed on the client

Harvard University Java Application Connections

Harvard University Web Connections

Harvard University Listener Connection

Harvard University Client/Server

Harvard University Oracle Network  The Oracle Net software must be installed on the Application Server and the Database Server, for 3-tier applications  Oracle Net is also used to connect distributed databases

Harvard University Application Server

Harvard University Server to Server

Harvard University Oracle Networks  The Oracle Net for versions Oracle10g and Oracle11g, supports connections to databases running versions or higher  Each object in a database is uniquely identified by it’s owner and it’s name  With synonyms we learned that the fully qualified object name, included the server name and the instance name, the owner and the object’s name

Harvard University Oracle Networks  Oracle Net relies on a series of configuration files  The main file is the tnsnames.ora file  It is by default located in the /$ORACLE_HOME/network/admin directory  From Oracle8i onwards, we need to use the TNS_ADMIN shell variable

Harvard University Oracle Networks  This variable specifies the location of the tnsnames.ora file.  It can also be stored in a general directory, like /var/opt/oracle or /etc

Harvard University Architecture  The 3 main files for Oracle Net and SQL*Net V2 are – Tnsnames.ora – Listener.ora – Sqlnet.ora  They are located in the directory identified by the TNS_ADMIN variable  echo $TNS_ADMIN /u01/app/oracle/product/11.1.0/network/admin

Harvard University Architecture  The sqlnet.ora holds some of the parameter settings for sql*net  The listener.ora file specifies the configuration of the listener  The tnsnames.ora file defines the sid- mappings used to connect to a database.  It is used by both the client and server, to connect to the database

Harvard University Application Server

Harvard University Tnsnames  This file can hold connect descriptors to many databases  The connect descriptor specifies the communications protocol, server name and the instance name

Harvard University Connect Descriptors  Every database requires a connect descriptor.  A connect descriptor describes the location of the network listener and the system identifier (SID) of the database to which to connect.  Database connect descriptors commonly consist of two sections: – the listener ADDRESS – the database SID

Harvard University CLASS.HARVARD.EDU = ----This is an alias name (DESCRIPTION = (ADDRESS = (COMMUNITY = TCP.edu) (PROTOCOL = TCP) (Host = kermit.dce.harvard.edu) (Port = 1521)) (CONNECT_DATA = (SID = E256))) Connect Descriptors

Harvard University Tnsnames  The protocol is TCP  The HOST kermit.dce.harvard.edu, is fully qualified  The default port is 1521, another choice is These are the default ports that Oracle Net uses.  You can choose you own, for security

Harvard University Tnsnames  CLASS.HARVARD.EDU is a service name or alias  All the service names with their associated connect descriptors are stored in the tnsnames.ora file.  All service names must be unique within the tnsnames file

Harvard University Tnsnames  To connect to a database using the user scott and the password tiger, use the following connect string sqlplus>

Harvard University Tnsnames  The Oracle Net Assistant tool can generate the connect descriptor

Harvard University Listeners  Each database server must have a listener.ora  The listener.ora file lists the names and addresses of all the listener processes on the machine and the instances they support  The Listener receives connections from Oracle Net and SQL*Net V2 clients

Harvard University Listeners  The listener.ora file is broken into 4 parts – The header section – The address list – The instance definitions – Operational parameters

Harvard University Listeners = -- The default name is LISTENER (ADDRESS_LIST = (ADDRESS= (PROTOCOL= IPC)(KEY= E253)) (ADDRESS= (PROTOCOL= IPC)(KEY= E256)) (ADDRESS(PROTOCOL=TCP)(Host=kermit) (Port= 1521)) )

Harvard University Listeners SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (GLOBAL_DBNAME=E256.HARVARD.EDU) (ORACLE_HOME=/u01/app/oracle/product/11.1.0) (SID_NAME = E256) )

Harvard University Operational Parameters STARTUP_WAIT_TIME_LISTENER = 0 ( startup immediately, it is the time in seconds the listener will wait to start, after the startup command) CONNECT_TIMEOUT_LISTENER = 10 ( time, in seconds, before listener will accept new connections) TRACE_LEVEL_LISTENER = OFF (admin,user,support)

Harvard University Operational Parameters LOGGING = ON ( OFF) LOG_FILE = name of listener log file LOG_DIRECTORY = the directory for the listener log file TRACE_FILE = name of listener trace file TRACE_DIRECTORY = the directory for the listener trace file

Harvard University Operational Parameters  In Oracle 10g and Oracle11g the database instances register themselves with the listener upon database startup

Harvard University lsnrctl SunOS kermit 5.8 > lsnrctl LSNRCTL for Solaris: Version (c) Copyright 1998 Oracle Corporation. All rights reserved. Welcome to LSNRCTL, type "help" for information. LSNRCTL>

Harvard University lsnrctl LSNRCTL> help The following operations are available An asterisk (*) denotes a modifier or extended command: start stop status services version reload save_config trace spawn dbsnmp_start dbsnmp_stop dbsnmp_status change_password debug test quit exit set* show*

Harvard University lsnrctl  LSNRCTL>start -- To start the listener  SunOS kermit 5.8 >lsnrctl start  LSNRCTL>stop -- To stop the listener  SunOS kermit 5.8 >lsnrctl stop

Harvard University lsnrctl  EXIT or QUIT exits lsnrctl  RELOAD allows the changing of the listener services after the listener has been started  SAVE_CONFIG creates a backup of your existing listener.ora and updates the listener.ora file with the changed parameters

Harvard University lsnrctl  SET can be used to define parameter values

Harvard University Debugging  telnet (ssh ) host_name  ping host_name  tnsping  LSNRCTL> status E256

Harvard University Debugging  SunOS kermit 5.8 > ps -eaf | grep tns  oracle :59:28 ? 0:01 /u01/app/oracle/product/11.1.0/bin/tnslsnr LISTENER –inherit

Harvard University EZConnect  Must have 10g or later client installed  Connect  Connect  For JDBC use Connect  Sql*net.ora file must contain names.directory_path = (tnsnames EZCONNECT)

Harvard University The Oratab File  Created when the rdbms is installed.  It’s location is dependent on the operating system used. For Solaris, its is located in /var/opt/oracle  It contains a line for each database

Harvard University The Oratab File SunOS kermit 5.8 > vi oratab  This file is used by ORACLE utilities. It is created by root.sh  A colon, ':', is used as the field terminator. A new line terminates the entry. Lines beginning with a pound sign, '#', are comments. # Entries are of the form: # $ORACLE_SID:$ORACLE_HOME: : E253:/u01/app/oracle/product/11.1.0dev:Y E256:/u01/app/oracle/product /11.1.0dev:N

Harvard University The Oratab File  The first and second fields are the system identifier and home directory of the database respectively. The third field indicates to the dbstart utility that the database should, "Y", or should not, "N", be brought up at system boot time.  Multiple entries with the same $ORACLE_SID are not allowed.

Harvard University Reading  Oracle11g Net Services Administrator's Guide – Chap5 Architecture of Oracle Net Services

Harvard University Mid-Term  Next week  Open book  I will the exam to all at 5:30PM next week  It will also be posted on the website  You have 24 hours to complete and return the exam.  It must be returned by 5:30PM Thursday  Others can come to class and do the exam here.