NETWORK MANAGEMENT can be defined as monitoring, testing, configuring and trouble shooting network components to meet a set of requirements defined by an organization.
Set of requirements include the smooth, efficient operation of the network that provides the predefined quality of service for users
A network management system (NMS) refers to a collection of applications that enable network
components to be monitored and controlled.
network management systems have the same basic architecture, a
A network management system (NMS) refers to a collection of applications that enable network
components to be monitored and controlled.
network management systems have the same basic architecture, a
SNMP is a tool (protocol) that allows for remote and local management of items on the network including servers, workstations, routers, switches and other managed devices.
•It is an application level protocol and is designed for application layer so that it can monitor devices made by different manufacturers and installed on different physical networks.
•In other words SNMP frees management tasks from both the physical characteristics of managed devices and the underlying network technology.
•It is based on the concept of manager and agent.
–Agent - process running on each managed node collecting information about the device it is running on. It is a router or a host that runs SNMP server program
–Manager - process running on a management workstation that requests information about devices on the network. It is a host that runs the SNMP client program.
I gave this presentation 3 times, regarding the demo the first time I used CISCO
packet tracer (simulator) by configuring the router with the SNMP configuration and
adding a community-string then browsing the router elements via an MIB browser from
any pc connected to the router.
the second and third times I made a live demo by using the (pure PERL SNMP library)
and writing a small PERL script using the functions from it and connected my laptop
to the configured router using putty..
pure PERL SNMP library link:
http://code.google.com/p/snmp-session/
The Distance Vector Multicast Routing Protocol (DVMRP), defined in RFC 1075, is a routing protocol used to share information between routers to facilitate the transportation of IP multicast packets among networks. It formed the basis of the Internet's historic multicast backbone, Mbone.
The protocol is based on the Routing Information Protocol (RIP).[1] The router generates a routing table with the multicast group of which it has knowledge with corresponding distances (i.e. number of devices/routers between the router and the destination). When a multicast packet is received by a router, it is forwarded by the router's interfaces specified in the routing table.
DVMRP operates via a reverse path flooding technique, sending a copy of a received packet (specifically IGMP messages for exchanging routing information with other routers) out through each interface except the one at which the packet arrived. If a router (i.e. a LAN which it borders) does not wish to be part of a particular multicast group, it sends a "prune message" along the source path of the multicast.
This study guide is intended to provide those pursuing the CCNA certification with a framework of what concepts need to be studied. This is not a comprehensive document containing all the secrets of the CCNP nor is it a “braindump” of questions and answers.
I sincerely hope that this document provides some assistance and clarity in your studies.
SNMP is a tool (protocol) that allows for remote and local management of items on the network including servers, workstations, routers, switches and other managed devices.
•It is an application level protocol and is designed for application layer so that it can monitor devices made by different manufacturers and installed on different physical networks.
•In other words SNMP frees management tasks from both the physical characteristics of managed devices and the underlying network technology.
•It is based on the concept of manager and agent.
–Agent - process running on each managed node collecting information about the device it is running on. It is a router or a host that runs SNMP server program
–Manager - process running on a management workstation that requests information about devices on the network. It is a host that runs the SNMP client program.
I gave this presentation 3 times, regarding the demo the first time I used CISCO
packet tracer (simulator) by configuring the router with the SNMP configuration and
adding a community-string then browsing the router elements via an MIB browser from
any pc connected to the router.
the second and third times I made a live demo by using the (pure PERL SNMP library)
and writing a small PERL script using the functions from it and connected my laptop
to the configured router using putty..
pure PERL SNMP library link:
http://code.google.com/p/snmp-session/
The Distance Vector Multicast Routing Protocol (DVMRP), defined in RFC 1075, is a routing protocol used to share information between routers to facilitate the transportation of IP multicast packets among networks. It formed the basis of the Internet's historic multicast backbone, Mbone.
The protocol is based on the Routing Information Protocol (RIP).[1] The router generates a routing table with the multicast group of which it has knowledge with corresponding distances (i.e. number of devices/routers between the router and the destination). When a multicast packet is received by a router, it is forwarded by the router's interfaces specified in the routing table.
DVMRP operates via a reverse path flooding technique, sending a copy of a received packet (specifically IGMP messages for exchanging routing information with other routers) out through each interface except the one at which the packet arrived. If a router (i.e. a LAN which it borders) does not wish to be part of a particular multicast group, it sends a "prune message" along the source path of the multicast.
This study guide is intended to provide those pursuing the CCNA certification with a framework of what concepts need to be studied. This is not a comprehensive document containing all the secrets of the CCNP nor is it a “braindump” of questions and answers.
I sincerely hope that this document provides some assistance and clarity in your studies.
While doing programming in any programming language, you need to use various variables to store various information. Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in memory.
You may like to store information of various data types like character, wide character, integer, floating point, double floating point, boolean etc. Based on the data type of a variable, the operating system allocates memory and decides what can be stored in the reserved memory.
CS4443 - Modern Programming Language - I Lecture (2)Dilawar Khan
Topic Covered:
================================================
Basic Data Types and their Mapping to CTS
Variables, Constants, and Operators
Working with Flow Control and Conditional Statements
Type Conversion, String Manipulation and Complex Variable Types
Arrays in C#
foreach loop
CPU Organization & Functionality
CPU Organization
Fundamental and features
Data Representation
Basic Formats
Fixed and Floating Representation
Instruction Set
Instruction Format
Type and Programming Consideration
Addressing Mode
Fixed –Point Arithmetic Multiplication Algorithm
Hardware Algorithm
Booth Multiplication Algorithm
The IP addresses used to identify systems on a TCP/IP network. The IP address is an absolute identifier of both the individual machine and the network on which it resides.
Every IP datagram packet transmitted over a TCP/IP network contains the IP addresses of the source system that generated it and the destination system for which it’s intended in its IP header.
A ‘Baseband’ Network is one in which the cable or other network medium can carry only a single signal at any one time.
A ‘Broadband’ network on the other hand can carry multiple signals simultaneously, (using a discrete part of the cables bandwidth for each signal.)
As an example of broadband network, consider the cable television service that you probably have in your home. Although only one cable runs at your TV, it supplies you with dozens of channels of programming at the same time.
Knowledge discovery is a new field that combines several techniques from computer science and Artificial Intelligence.
Search for relations and global patterns in large databases.
It is defined as a non-trivial extract of implicit, unknown, and potential user information from databases.
ADVANCE DATABASE MANAGEMENT SYSTEM CONCEPTS & ARCHITECTURE by vikas jagtapVikas Jagtap
The data that indicates the earth location (latitude & longitude, or height & depth ) of these rendered objects is known as spatial data.
When the map is rendered, objects of this spatial data are used to project the location of the objects on 2-Dimentional piece of paper.
The spatial data management systems are designed to make the storage, retrieval, & manipulation of spatial data (i.e points, lines and polygons) easier and natural to users, such as GIS.
While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to process spatial data types.
These are typically called geometry or feature.
Overview of Object-Oriented Concepts Characteristics by vikas jagtapVikas Jagtap
Object-oriented data base systems are proposed as alternative to relational systems and are aimed at application domains where complex objects play a central role.
The approach is heavily influenced by object-oriented programming languages and can be understood as an attempt to add DBMS functionality to a programming language environment
This ppt show how your age has being going from childhood to old age .what old man want to say to his child .
how parents play a vital role where there children are kids
Dubai is the most populous city and emirate in the United Arab Emirates, and the second largest emirate by territorial size after the capital, Abu Dhabi.
Area: 4,114 km²
Founded: June 9, 1833
Local time: Sunday 2:41 pm
Weather: 28°C, Wind W at 27 km/h, 48% Humidity
Population: 2.106 million (2013)
GDP per capita: 16,350.00 USD (2005)
Gross domestic product: 82.11 billion USD (2008)
Java applications cannot directly communicate with a database to submit data and retrieve the results of queries.
This is because a database can interpret only SQL statements and not Java language statements.
For this reason, you need a mechanism to translate Java statements into SQL statements.
The JDBC architecture provides the mechanism for this kind of translation.
The JDBC architecture can be classified into two layers :
JDBC application layer.
JDBC driver layer.
JDBC application layer : Signifies a Java application that uses the JDBC API to interact with the JDBC drivers. A JDBC driver is software that a Java application uses to access a database. The JDBC driver manager of JDBC API connects the Java application to the driver.
JDBC driver layer : Acts as an interface between a Java applications and a database. This layer contains a driver , such as a SQL server driver or an Oracle driver , which enables connectivity to a database.
A driver sends the request of a Java application to the database. After processing the request, the database sends the response back to the driver. The driver translates and sends the response to the JDBC API. The JDBC API forwards it to the Java application.
JSP technology has facilitated the segregation of the work of a Web designer and a Web developer.
A Web designer can design and formulate the layout for the Web page by using HTML.
On the other hand, a Web developer working independently can use java code and other JSP specific tags to code the business logic.
The simultaneous construction of the static and dynamic content facilitates development of quality applications with increased productivity.
Server side programs can be written using different server-side technologies , such as Common Gateway Interface (CGI) , Active Server Pages (ASP) and Servlets.
CGI scripts are written in C , C++ or perl programming languages .
In case of an application server using CGI script to process client request , the server creates a separate instance of the CGI script to process the request.
As a result, the efficiency of the server is affected when there is large number of concurrent requests.
“Bluetooth wireless technology is an open specification for a low-cost, low-power, short-range radio technology for ad-hoc wireless communication of voice and data anywhere in the world.”
An Introduction to BLUETOOTH TECHNOLOGYVikas Jagtap
“Bluetooth wireless technology is an open specification for a low-cost, low-power, short-range radio technology for ad-hoc wireless communication of voice and data anywhere in the world.”
THREATS are possible attacks.
It includes
The spread of computer viruses
Infiltration and theft of data from external hackers
Engineered network overloads triggered by malicious mass e-mailing
Misuse of computer resources and confidential information by employees
Unauthorized financial transactions and other kinds of computer fraud conducted in the company's name
Electronic inspection of corporate computer data by outside parties
Damage from failure, fire, or natural disasters
The DNS name space is based on a domains, which exist in a hierarchical structure much like the directory tree in a file system.
A domain is the equivalent of a directory, in that it can contain either subdomains (subdirectories) or hosts (files), forming a structure called DNS tree.
The DNS name space function in the same way : administrators are assigned domain names and are then responsible for specifying host names to systems within that domain.
The result is that every computer on the Internet is uniquely identifiable by a DNS, name that consists of host name plus the names of all its parent domains, stretching up to the root of the DNS tree, separated by periods.
Each of the names between the periods can be up to 63 characters long, with a total length of 255 characters for a complete DNS name.
Domain and host names are not case sensitive, and can take any value except the null value.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
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Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Epistemic Interaction - tuning interfaces to provide information for AI support
Simple Network Management Protocol by vikas jagtap
1.
2. NETWORK MANAGEMENT
• NETWORK MANAGEMENT can be defined as
monitoring, testing, configuring and trouble shooting
network components to meet a set of requirements
defined by an organization.
• Set of requirements include the smooth, efficient
operation of the network that provides the
predefined quality of service for users.
• Functions of Network Management System
- Configuration management
- Fault management
- Performance management
- Security management
- Accounting management
3. SNMP- Simple Network Management Protocol
• The SNMP is a framework for managing devices in an
internet using the TCP/IP protocol suite.
• It provides a set of fundamental operations for
monitoring and maintaining an internet devices.
• Concept: SNMP uses the concept of manager and
agent.
4. SNMP- Managers and Agents
• A management station, called a manager, is a host
computer that runs the SNMP client program.
• A managed station, called as an agent, is a router (or a
host) that runs the SNMP server program.
• Management is achieved through simple interaction
between a manager and an agent.
• Management with SNMP is based on 3 basic idea.
1) A manager checks an agent by requesting
information in the form of variables that reflects the
behavior of the agent.
2) A manager forces an agent to perform a task by
resetting values of variables in the agent database.
3) An agent contributes to the management process by
warning the manager of an unusual situation (reboot).
5. MANAGEMENT Components
• To do the management task, SNMP uses two other
protocols: Structure of Management Information (SMI)
and Management Information Base (MIB).
• Means, Management on the Internet is done through the
cooperation of the three protocols SNMP, SMI and MIB.
6. MANAGEMENT Components
Role of SNMP
• It defines the format of the packet to be sent from a manager
to an agent and vice versa.
• It also interprets the result and creates statistics.
• The packets exchanged contain the object (variable) names
and their status (values).
• SNMP is responsible for reading and changing these values.
Role of SMI
• It defines the general rules for naming objects, defining
object types (including range and length), and showing how
to encode objects and values.
• SMI does not define the number of objects an entity should
manage or name the objects to be managed or define the
association between the objects and their values.
7. MANAGEMENT Components
Role of MIB
• For each entity to be managed, this protocol must define the
number of objects, name them according to the rules defined
by SMI, and associate a type to each named object.
• MIB creates a set of objects defined for each entity similar to
a database.
An Analogy
• We can compare the task of network management to the
task of writing a program.
- both tasks need rules, in network management this is
handled by SMI.
- both tasks need variable declaration, in network
management this is handled by MIB.
- both tasks have actions performed by statements, in
network management this is handled by SNMP.
8. MANAGEMENT Components
Structure of Management Information (SMI)
• The SMI, version 2 (SMIv2) is a component for network
management. Performs the functions such as
- To name objects.
- To define the type of data that can be stored in an object.
- To show how to encode data for transmission over the
network.
• SMI is guideline for SNMP, it emphasizes three attributes to
handle an object: name, data type and encoding method.
9. Structure of SMI
Name
• The SMI, requires that each managed object (such as a
router, a variable in a router, a value) have a unique name.
• To name objects globally, SMI uses an “Object Identifier”,
which is a hierarchical identifier based on tree structure.
• Tree structure starts with an unnamed root, each object can
be defined by using a sequence of integers separated by dots
(used by SNMP).
• Tree structure can also define an object by using a sequence
of textual names separated by dots (used by people).
- for example:
iso.org.dod.internet.mgmt.mib 1.3.6.1.2.1
The objects that are used in SNMP are located under mib
object, so their identifiers always starts with 1.3.6.1.2.1
11. Structure of SMI
Type of data
• The second attribute of an object is the type of data stored in it.
• To define the data type, SMI uses fundamental Abstract
Syntax Notation 1 (ASN.1) definitions and adds some new
definitions i.e. SMI is both a subset and superset of ASN.1.
• It has 2 categories of data types: simple and structured.
12. Structure of SMI
Type of data
• Simple data type: the first five are from ASN.1; next seven
are defined by SMI.
Type Size Description
INTEGER 4 bytes An integer with a value between -231
and 231
-1
Integer32 4 bytes Same as INTEGER
Unsigned32 4 bytes Unsigned with value between 0 and 232
-1
OCTECT STRING Variable Byte string up to 65,535 bytes long
OBJECT
IDENTIFIER
Variable An Object Identifier
IPAddress 4 bytes An IP Address made of 4 integers
Counter32 4 bytes An Integer whose value can be incremented from 0 to 232
; when
it reaches its maximum value, it wraps back to 0
Counter64 8 bytes 64-bit counter
Gauge32 4 bytes Same as Counter32, but when it reaches its maximum value, it
does not wrap; it remains there until it is reset.
TimeTicks 4 bytes A counting value that records time in 1/100 second
BITS A string of bits
Opaque Variable Un interpreted string
13. Structure of SMI
Type of data
• Structured data type: SMI defines two structured data types-
Sequence and Sequence of.
• Sequence: it is a combination of simple data types, not
necessarily same type. It is like the concept of struct in C.
• Sequence of: it is a combination of simple data types all of
same type. It is like the concept of array in C.
14. Structure of SMI
Data Encoding Method
• SMI uses standard, Basic Encoding Rules (BER), to encode
data to be transmitted over the network.
• BER specifies each piece of data be encoded in triplet format:
tag, length and value.
• Tag: it is a 1 byte field that defines the type of data. It consist
of 3 subfields: class (2bits), format (1bit) and number (5bits).
- Class field defines the scope of the data: four classes are
defined: Universal (00), application wide (01), context specific
(10) and private (11).
15. Structure of SMI
Data Encoding Method
• The Universal (00) data types are taken from ASN.1
(INTEGER, OCTECT STRING, and ObectIdentifier).
• The Application wide (01) are added by SMI (IPAddress,
Counter, Gauge and TimeTicks).
• The 5 context-specific (10) data types have meanings
that may change from one protocol to another.
• The private (11) data types are vendor specific.
• The format subfield indicates whether the data are
simple (0) or structured (1).
• The number subfield further divides simple or structured
data into subgroups for example: in the universal class,
with simple format, INTEGER has a value of 2, OCTECT
STRING has a value of 4 and so on.
16. Structure of SMI
Data Encoding Method
• Length: it is 1 or more bytes. If it is 1 byte, the MSB is 0,
the other 7 bits defines the length of data. If it is more
than 1 byte, the MSB of the first byte must be 1 and
other 7 bits defines the number of bytes needed to define
the length.
• Value: it codes the value of the data according to the
rules defined in BER
0
17. Structure of SMI
Data Encoding Method
• Following table shows the data types and their tags in binary
and Hexadecimal numbers.
Data Type Class Format Number Tag
(Binary)
Tag
(Hex)
INTEGER 00 0 00010 00000010 02
OCTECT STRING 00 0 00100 00000100 04
OBJECT IDENTIFIER 00 0 00110 00000110 06
NULL 00 0 00101 00000101 05
Sequence, Sequence of 00 1 10000 00110000 30
IPAddress 01 0 00000 01000000 40
Counter 01 0 00001 01000001 41
Gauge 01 0 00010 01000010 42
TimeTicks 01 0 00011 01000011 43
Opaque 01 0 00100 01000100 44
18. Structure of SMI
Data Encoding Method
• Just to show how these three fields: tag, length and value
are used to define objects, for example: how to define
INTEGER 14.
• Another example: how to define OCTECT STRING “HI”.
19. MIB (Management Information Base)
MIB Version 2 (MIB2) is a second component used in network
management.
• Each agent has its own MIB2, which is a collection of all
objects that the manager can manage.
• The objects in MIB2 are categorized under 10 different
groups: system, interface, address translation, ip, icmp, tcp,
udp, egp, transmission and snmp.
• These groups are under MIB2 object in the object identifier
tree. Each group has defined variables and/ or tables.
20. MIB (Management Information Base)
Following is a brief description of some of the objects.
• sys: system object defines general information about the node
(system) such as name, location, and lifetime.
• if: interface object defines information about all the interfaces of
the node including interface no. physical address and IP address.
• at: address translation object defines information about the ARP
table.
• ip: this object defines information related to IP (routing table, IP
address).
• icmp: this object defines information about the ICMP (no. of
packets sent and received and total errors created).
• tcp: this object defines information about the TCP (connection
table, time-out value, no. of ports and no. of packets sent and
received ).
• udp: this object defines information about the UDP ( no. of ports
and no. of packets sent and received ).
• Snmp: this object defines information about SNMP (itself).
21. MIB (Management Information Base)
Accessing MIB variables.
• Simple variables: to access the simple variables, we use the id of
the group followed by the id of the variable. Following figure shows
how to access each variable.
For example: we use the group udp, then variables under udp group
can be accessed as follows.
udpInDatagrams 1.3.6.1.2.1.7.1
udpNoPorts 1.3.6.1.2.1.7.2
udpInErrors 1.3.6.1.2.1.7.3
22. SNMP (Simple Network Management Protocol)
SNMP uses both SMI and MIB in Internet network management. It 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.
3. An agent to send an alarm message about an abnormal situation
(such as it’s rebooting) to the manager.
PDUs
SNMPv3 defines eight types of packets (or PDUs): GetRequest,
GetNextRequest, GetBulkRequest, SetRequest, Response,
Trap, InformRequest and Report.
GetRequest: it is sent from the manager (client) to the agent
(server) to retrieve the value of a variable or a set of variables.
GetNextRequest: it is sent from the manager (client) to the agent
(server) to retrieve the value of a variable. It is mostly used to
retrieve the values of the entries in a table.
GetBulkRequest: it is sent from the manager (client) to the agent
(server) to retrieve a large amount of data. It can be used
instead of above two PDUs
23. SNMP (Simple Network Management Protocol)
PDUs
SetRequest: it is sent from the manager (client) to the agent
(server) to set (store) a value in a variable.
Response: it is sent from an agent (server) to the manager
(client) in response to GetRequest or GetNextRequest. It
contains the values of the variables requested by manager.
Trap: the trap PDU is sent from the agent (server) to the
manager (client) to report an event, for example: if the agent
is rebooted, it informs the manager and reports the time of
rebooting.
InformRequest: it is sent from one manager (client) to another
remote manager to get the value of some variables from
agents under the control of the remote manager. The remote
manager responds with a Response PDU.
Report: the Report PDU is designed to report some types of
errors between managers. It is not yet in use.
25. SNMP: PDUs Format
The format of the eight SNMP PDUs shown in figure. The
GetBulkRequest PDU differs from the others in two areas.
1) Error status and error index values are zeros for all
request messages except GetBulkRequest.
2) Error status field is replaced by nonrepeater field and
error index field is replaced by max-repetitions field in
GetBulkRequest.
PDU
type
Request
ID
Error
status
Error
index
Variable Value Variable Value
VarBind list
PDU
26. SNMP: PDUs Format
PDU type: it defines the type of PDU.
Request ID: it is a sequence number used by the manager in a
Request PDU and repeated by the agent in a response. It is
used to match a request to a response.
Error status: it is a integer used only in Response PDUs to
show the types of errors reported by the agent. It’s value is 0
in a Request PDUs.
Nonrepeaters: it is used only in GetBulkRequest and replaces
the error status field, which is empty in Request PDUs.
Error index: it is an offset that tells the manager which variable
caused the error.
Max-repetition: it is used only in GetBulkRequest and replaces
the error index field, which is empty in Request PDUs.
VarBind list: it is a set of variables with corresponding values the
manager wants to retrieve or set. The values are null in
GetRequest and GetNextRequest.
27. SNMP: Messages
SNMP does not send only a PDU,
it sends the PDU in message.
In SNMPv3 a message consist of
four elements: version, header,
security parameters and data.
Version: defines the current
version 3.
Header: contains value for
message identification,
maximum message size etc.
Security parameter: is used to
create a message digest.
Data: the data contains the PDU
data.
PDU
Request ID
Error status
Error index
VarBind list
.
.
Object Identifier
Value to be stored
Data
Context engine ID
Context name
Security parameter
Version
Header
Message
28. SNMP: Codes for SNMP Messages
Data Class Format Number Whole Tag
(Binary)
Whole Tag
(Hex)
GetRequest 10 1 00000 10100000 A0
GetNextRequest 10 1 00001 10100001 A1
Response 10 1 00010 10100010 A2
SetRequest 10 1 00011 10100011 A3
GetBulkRequest 10 1 00101 10100101 A5
InformRequest 10 1 00110 10100110 A6
Trap(SNMPv2) 10 1 00111 10100111 A7
Report 10 1 01000 10101000 A8
29. SNMP
Types of Errors:
Status Name Meaning
0 noError No error
1 tooBig Response too big to fit in one
message
2 noSuchName Variables does not exist
3 badValue The value to be stored is invalid
4 readOnly The value can not be modified
5 genErr Other errors
UDP Ports:
SNMP uses the services of UDP on two well-known ports, 161 and
162.
- the well known port 161 is used by the server (agent).
- the well known port 162 is used by the client (manager).
30. SNMP: Security
The main difference between SNMPv3 and
SNMPv2 is the enhanced security.
- SNMPv3 provides two types of security:
general (SNMPv2) and specific (Security
parameter added in the header).
-SNMPv3 provides message authentication,
privacy and manager authentication.
- In addition to this SNMPv3 allows a manager
to remotely change the security configuration.
31. SNMP: Specific Problems
• Work on SNMP security took many many years to finally
result in a stable and accepted SNMPv3 specification.
• Other urgently needed improvements were kept on hold
during this time.
• One such problem is the inefficiency of SNMP for retrieving
bulk MIB data.
- SNMP shows poor performance when retrieving several
thousands of MIB variables in a single logical transaction.
Reasons:
– Lack of flow control
– Bandwidth inefficiency due to OID naming overhead
– High latency caused by a large number of
request/response interactions.
• Extensions to the SMI data definition language needed to
simplify, generalize and harmonize data definitions.