Application layer protocol

Application Layer Protocol Amitava Nag Assistant Professor amitavanag.09@gmail.com April 6, 2012 Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 1 / 37

Architecture of WWW Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 2 / 37

Architecture of WWW The WWW is a distributed client-server service, in which a client using a browser can access a service using a server. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 2 / 37

Architecture of WWW The WWW is a distributed client-server service, in which a client using a browser can access a service using a server. The service provided is distributed over many locations called sites. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 2 / 37

Architecture of WWW Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 3 / 37

Browser Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 4 / 37

Internet apps: application, transport protocols Application Application layer Underlying protocol transport protocol email SMTP[RFC2821] TCP remote terminal Telnet[RFC854] TCP access web HTTP[RFC2616] TCP ﬁle transfer FTP[RFC959] TCP Remote File Server NFS UDP/TCP Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 5 / 37

Web Page Identiﬁer Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server - Protocol port number (optional) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server - Protocol port number (optional) - Path through servers ﬁle system (optional) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server - Protocol port number (optional) - Path through servers ﬁle system (optional) - Parameters (optional) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server - Protocol port number (optional) - Path through servers ﬁle system (optional) - Parameters (optional) - Query (optional) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web Page Identiﬁer Known as Uniform Resource Locator (URL) Encodes - Access protocol to use - Domain name of server - Protocol port number (optional) - Path through servers ﬁle system (optional) - Parameters (optional) - Query (optional) Format http: // hostname [: port] / path [; parameters] [? query] Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 6 / 37

Web and HTTP Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

Web and HTTP Web page consists of objects Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

Web and HTTP Web page consists of objects Object can be HTML ﬁle, JPEG image, Java applet, audio ﬁle, Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

Web and HTTP Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file, Web page consists of base HTML-file which includes several referenced objects Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

Web and HTTP Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file, Web page consists of base HTML-file which includes several referenced objects Each object is addressable by a URL Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

Web and HTTP Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file, Web page consists of base HTML-file which includes several referenced objects Each object is addressable by a URL Example URL:www.someschool.edu/someDept/pic.gif Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 7 / 37

HTTP Characteristics Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Stateless Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Stateless Permits bi-directional transfer Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Stateless Permits bi-directional transfer Oﬀers capability negotiation Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Stateless Permits bi-directional transfer Oﬀers capability negotiation Support for caching Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP Characteristics Application level Request / response paradigm Stateless Permits bi-directional transfer Oﬀers capability negotiation Support for caching Support for intermediaries Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 8 / 37

HTTP overview Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 9 / 37

HTTP overview ( continued ) Uses TCP : Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 10 / 37

HTTP overview ( continued ) Uses TCP : HTTP client initiates TCP connection (creates socket) to ( www.someschool.edu/ ) server on port 80 (default port number for HTTP). Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 10 / 37

HTTP overview ( continued ) Uses TCP : HTTP client initiates TCP connection (creates socket) to ( www.someschool.edu/ ) server on port 80 (default port number for HTTP). HTTP server accepts TCP connection from client Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 10 / 37

HTTP overview ( continued ) Uses TCP : HTTP client initiates TCP connection (creates socket) to ( www.someschool.edu/ ) server on port 80 (default port number for HTTP). HTTP server accepts TCP connection from client HTTP messages (application-layer protocol messages) exchanged between browser ( HTTP client ) and Web server ( HTTP server ) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 10 / 37

HTTP overview ( continued ) Uses TCP : HTTP client initiates TCP connection (creates socket) to ( www.someschool.edu/ ) server on port 80 (default port number for HTTP). HTTP server accepts TCP connection from client HTTP messages (application-layer protocol messages) exchanged between browser ( HTTP client ) and Web server ( HTTP server ) TCP connection closed Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 10 / 37

HTTP connections Nonpersistent HTTP Persistent HTTP At most one object is sent over Multiple objects can be sent over a TCP connection. single TCP connection between client and server. HTTP/1.0 uses nonpersistent HTTP HTTP/1.1 uses persistent connections in default mode Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 11 / 37

FTP: the ﬁle transfer protocol Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host client/server model Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host client/server model client: side that initiates transfer (either to/from remote) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host client/server model client: side that initiates transfer (either to/from remote) server: remote host Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host client/server model client: side that initiates transfer (either to/from remote) server: remote host ftp: RFC 959 Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP: the ﬁle transfer protocol transfer ﬁle to/from remote host client/server model client: side that initiates transfer (either to/from remote) server: remote host ftp: RFC 959 ftp server: port 21 Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 12 / 37

FTP overview Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 13 / 37

FTP:connections Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 14 / 37

Opening the control connection Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 15 / 37

Creating the data connection Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 16 / 37

FTP: separate control, data connections Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. When server receives a command for a ﬁle transfer, the server opens a TCP data connection to client Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. When server receives a command for a ﬁle transfer, the server opens a TCP data connection to client After transferring one ﬁle, server closes connection. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. When server receives a command for a file transfer, the server opens a TCP data connection to client After transferring one file, server closes connection. Server opens a second TCP data connection to transfer another file. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. When server receives a command for a file transfer, the server opens a TCP data connection to client After transferring one file, server closes connection. Server opens a second TCP data connection to transfer another file. Control connection: out of band Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

FTP: separate control, data connections FTP client contacts FTP server at port 21, specifying TCP as transport protocol Client obtains authorization over control connection Client browses remote directory by sending commands over control connection. When server receives a command for a file transfer, the server opens a TCP data connection to client After transferring one file, server closes connection. Server opens a second TCP data connection to transfer another file. Control connection: out of band FTP server maintains state: current directory, earlier authentication Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 17 / 37

Remote Login: Telnet Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 18 / 37

Remote Login: Telnet TELNET is a general-purpose client-server application program Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 18 / 37

Remote Login: Telnet TELNET is a general-purpose client-server application program TELNET enables the establishment of a connection to a remote system in such a way that the local terminal appears to be a terminal at the remote system. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 18 / 37

Figure:Local login Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 19 / 37

Figure:Remote login Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 20 / 37

Electronic Mail Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 21 / 37

Electronic Mail Three major components: Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 21 / 37

Electronic Mail Three major components: 1 user agents Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 21 / 37

Electronic Mail Three major components: 1 user agents 2 mail servers Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 21 / 37

Electronic Mail Three major components: 1 user agents 2 mail servers 3 simple mail transfer protocol: SMTP Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 21 / 37

Electronic Mail Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 22 / 37

Electronic Mail: mail servers Mail Servers Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: mail servers Mail Servers mailbox contains incoming messages for user Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: mail servers Mail Servers mailbox contains incoming messages for user message queue of outgoing (to be sent) mail messages Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: mail servers Mail Servers mailbox contains incoming messages for user message queue of outgoing (to be sent) mail messages SMTP protocol between mail servers to send email messages Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: mail servers Mail Servers mailbox contains incoming messages for user message queue of outgoing (to be sent) mail messages SMTP protocol between mail servers to send email messages client: sending mail server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: mail servers Mail Servers mailbox contains incoming messages for user message queue of outgoing (to be sent) mail messages SMTP protocol between mail servers to send email messages client: sending mail server server: receiving mail server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 23 / 37

Electronic Mail: SMTP [RFC 2821] Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages closure Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages closure command/response interaction Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages closure command/response interaction commands: ASCII text Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages closure command/response interaction commands: ASCII text response: status code and phrase Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Electronic Mail: SMTP [RFC 2821] uses TCP to reliably transfer email message from client to server, port 25 direct transfer: sending server to receiving server three phases of transfer handshaking (greeting) transfer of messages closure command/response interaction commands: ASCII text response: status code and phrase messages must be in 7-bit ASCII Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 24 / 37

Scenario: Alice sends message to Bob Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu 2 Alices UA sends message to her mail server; message placed in message queue Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu 2 Alices UA sends message to her mail server; message placed in message queue 3 Client side of SMTP opens TCP connection with Bobs mail server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu 2 Alices UA sends message to her mail server; message placed in message queue 3 Client side of SMTP opens TCP connection with Bobs mail server 4 SMTP client sends Alices message over the TCP connection Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu 2 Alices UA sends message to her mail server; message placed in message queue 3 Client side of SMTP opens TCP connection with Bobs mail server 4 SMTP client sends Alices message over the TCP connection 5 Bobs mail server places the message in Bobs mailbox Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Scenario: Alice sends message to Bob 1 Alice uses UA to compose message and to bob@someschool.edu 2 Alices UA sends message to her mail server; message placed in message queue 3 Client side of SMTP opens TCP connection with Bobs mail server 4 SMTP client sends Alices message over the TCP connection 5 Bobs mail server places the message in Bobs mailbox 6 Bob invokes his user agent to read message Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 25 / 37

Figure: Alice sends message to Bob Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 26 / 37

Mail access protocols Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] authorization (agent < −− >server) and download Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] authorization (agent < −− >server) and download IMAP: Internet Mail Access Protocol [RFC 1730] Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] authorization (agent < −− >server) and download IMAP: Internet Mail Access Protocol [RFC 1730] more features (more complex) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] authorization (agent < −− >server) and download IMAP: Internet Mail Access Protocol [RFC 1730] more features (more complex) manipulation of stored msgs on server Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Mail access protocols SMTP: delivery/storage to receivers server Mail access protocol: retrieval from server POP: Post Oﬃce Protocol [RFC 1939] authorization (agent < −− >server) and download IMAP: Internet Mail Access Protocol [RFC 1730] more features (more complex) manipulation of stored msgs on server HTTP: Hotmail , Yahoo! Mail, etc. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 27 / 37

Figure:Mail access protocols Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 28 / 37

Network Management Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Monitoring, Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Monitoring, Control Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Monitoring, Control Today: automated, reliable diagnosis, and automatic control are still in a primitive stage Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Monitoring, Control Today: automated, reliable diagnosis, and automatic control are still in a primitive stage Architecture: Manager, Agents and Management Information Base (MIB) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Network Management Management = Initialization, Monitoring, Control Today: automated, reliable diagnosis, and automatic control are still in a primitive stage Architecture: Manager, Agents and Management Information Base (MIB) Observe that management-plane has a new interface to the network distinct from data and control-plane Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 29 / 37

Simple Network Management Protocol (SNMP) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 30 / 37

Simple Network Management Protocol (SNMP) SNMP is a framework for managing devices in an internet using the TCP/IP protocol suit Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 30 / 37

Simple Network Management Protocol (SNMP) SNMP is a framework for managing devices in an internet using the TCP/IP protocol suit A manager, usually a lost that, controls and monitor a set of agents,usually routers Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 30 / 37

Simple Network Management Protocol (SNMP) SNMP is a framework for managing devices in an internet using the TCP/IP protocol suit A manager, usually a lost that, controls and monitor a set of agents,usually routers The manager is a host that runs the SNMP client program. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 30 / 37

Simple Network Management Protocol (SNMP) SNMP is a framework for managing devices in an internet using the TCP/IP protocol suit A manager, usually a lost that, controls and monitor a set of agents,usually routers The manager is a host that runs the SNMP client program. The agent is a router or host that runs the SNMP server program Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 30 / 37

Figure:Mail access protocols Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 31 / 37

MANAGEMENT COMPONENTS Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 32 / 37

MANAGEMENT COMPONENTS SNMP requires the use of two other protocols: Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 32 / 37

MANAGEMENT COMPONENTS SNMP requires the use of two other protocols: 1 Structure of Management Information (SMI) and Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 32 / 37

MANAGEMENT COMPONENTS SNMP requires the use of two other protocols: 1 Structure of Management Information (SMI) and 2 Management Information Base (MIB) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 32 / 37

MANAGEMENT COMPONENTS SNMP requires the use of two other protocols: 1 Structure of Management Information (SMI) and 2 Management Information Base (MIB) Network management on the Internet is done through the cooperation of SNMP, SMI, and MIB. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 32 / 37

Management Information Base(MIB) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 33 / 37

Management Information Base(MIB) MIB is a second component used in network management Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 33 / 37

Management Information Base(MIB) MIB is a second component used in network management Each agent has its own MIB, a collection of all the objects that the manager can manage. Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 33 / 37

Figure:Management Information Base, version 2 (MIB2) Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 34 / 37

SNMP Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 35 / 37

SNMP SNMP is an application program that allows Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 35 / 37

SNMP SNMP is an application program that allows 1 a manager to retrieve the value of an object deﬁned in an agent; Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 35 / 37

SNMP SNMP is an application program that allows 1 a manager to retrieve the value of an object deﬁned in an agent; 2 a manager to store a value in an object deﬁned in an agent; and Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 35 / 37

SNMP SNMP is an application program that allows 1 a manager to retrieve the value of an object deﬁned in an agent; 2 a manager to store a value in an object deﬁned in an agent; and 3 an agent to send an alarm message about an abnormal situation to the manager Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 35 / 37

Figure:SNMP Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 36 / 37

The End Amitava Nag (Academy of Technology) Application Layer Protocol April 6, 2012 37 / 37

Application layer protocol

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