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NMS-18CS742 VTU Complete Notes

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Course

Network Management (18CS742)

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Module – 1

Data Communication & Network Management Overview

Analogy of Telephone Network Management

Why Telephone Network is popular?

The architecture of the Telephone network is hierarchical therefore it is reliable, dependable and hence

provides good Quality of Service(QoS). Because of this reason the need for data or computer

communication network management can be easily explained through an analogy of telephone network

management.

Telephone Network Model

The structure of a telephone network is depicted in the figure 1. Trunk is a logical link between two

switches-and may traverse one or more physical links that is the end office or Class 5. The end office is

the lowest in the hierarchy, is the local switching office. The dedicated link “loop” connects telephone

and the end office. The remaining four higher levels of switches, from Class 4 to Class 1 are tandem or

toll switches carrying toll (long-distance) calls. Now a day due to modern technology these four levels

are merged together and referred to as class 4. A direct trunk connects two end offices, a tall-connecting

trunk connects an end office to any toll office. and a toll trunk connects any two toll offices.

The direct distance dialing (DDD) network, enables the user to dial far-end telephone with

assistance of an operator. It comprises following 3 transmission trunks:

 A direct trunk connects to end offices

 A toll connecting trunk connects an end office to any toll office

 A toll trunk connects any to toll offices

A circuit connection is set up either directly using a local trunk or via the higher level switches & routes.

Primary & secondary routes are already programmed into the switch. If the primary route is

broken or the facilities over the primary route are filled to capacity, an alternative route is

automatically assigned.

Operations support systems ensure the quality of service in the telephone network.

NOCs (Network Operations Center) are available in all regions to monitor the global status of the

network. Hence the NOCs are considered as center of a telephone network operations.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Figure 1: Telephone Network Model

Data (Computer) & Telecommunication Networks

The data can be transmitted in one of 3 modes:

Circuit switched
Message switched or
Packet switched

In the circuit switched mode, a physical circuit is established between the originating &

terminating ends before the data is transmitted. The circuit is disconnected once the transmission

is completed.

In message-switched & packet-switched modes, the data is broken into packets & each packet is

enveloped with the destination & originating addresses.

Message-switched mode is used to send long messages such as email. The Packet switched mode

is used to transmit small packets. This mode is used in applications such as interactive

communication.

The bridges & routers open each packet to find the destination address & switch the data to the

appropriate output links.

In message switched mode, the data is stored by the system & then retrieved by the user at a later

time. In packet switched mode, the packets are fragmented & reassembled in almost real time.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

remote hosts.

Processor-to-processor communications over the telecommunications lines takes less time &

therefore are less expensive.

Figure 3: Telecommunication Network with PBX

DCE (Distributed Computing Environment) Simple Client/Server Model

The client initiates a request to the server & waits (Figure: 4 ).

The server executes the process to provide the requested service & sends the results to the client.

The client cannot initiate a process in the server. Thus, the process should have already been

started in the server & be waiting for requests to be processed.

Figure 4: Simple Client – Server Model

Model Of Client/Server Network in a DCE

Each client's request is normally processed by the server according to the FIFO rule (Figure:

5 ). This delay could be minimized, but not eliminated by concurrent processing of requests by

the server.

Since the client & application processes are running in a distributed computing environment, each

of them can be designed to execute a specific function efficiently.

The three processes, the client, the mail server and the DNS, are considered cooperative

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

computing processes & may be running in three separate platforms on remote LANs

connected by a WAN. The communication between these processes is called peer- to – peer

communication.

Figure 5: A Model of a client – Server Network in a DCE

TCP/IP-Based Networks: The Internet and Intranet

TCP/IP is a suite of protocols that enable networks to be interconnected.

TCP/IP forms the basic foundation of the Internet( Figure:6).

The nodes in the network use network protocol named IP to route packets.

IP is a connectionless protocol. That means there is no guarantee that the packets will be

delivered to the destination node. However, end-to-end communication can be guaranteed by

using the transport protocol, TCP.

TCP is connection-oriented protocol. The UDP protocol is a connectionless protocol.

Most of Internet traffic uses UDP/IP, because of its reliability in data transmission.

The Internet is a network of networks. Whereas, An intranet is a private network & access to it

is controlled by the enterprise that owns it, whereas the Internet is public.

Gateways between LANs serve as the interfaces between dissimilar & independent,

autonomous networks & perform many functions including protocol conversions.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Figure 7 : Internet Fabric Model

Communication Protocols and Standards Communication Architecture

Communication between users occurs at various levels.

Each system can be divided into 2 broad sets of communication layers. The top set of layers

consists of the application layers & the bottom set of the transport layers.

The users interface with the application level layer & the communication equipment interfaces

with the physical medium.

In Figure:8a, direct communication occurs between the corresponding cooperating layers of each

system.

In Figure:8b, the end systems communicating via an intermediate system N, which enables the

use of different physical media for the 2 end systems.

The transport layer information is converted into the appropriate protocols by the intermediate system

(system N).

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Figure 8: Basic Communication Architecture

OSI Communication Architecture

OSI model was developed based on the premise that the different layers of protocol provide

different services, and that each layer can communicate with only its own neighboring level

(Figure: 9 ).

Two systems can communicate on a peer-to-peer level i. at the same level of the protocol.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

OSI Layers & Services

Physical layer

Transfers to & gathers from the physical medium raw bit data.

Handles physical & electrical interfaces to the transmission medium.

Data link layer

Consists of two sub layers: LLC(Logical link control) & MAC(Medium access control).

LLC formats the data to go on the medium, performs error control & flow control.

MAC controls data transfer to & from LAN, resolves conflicts with other data on LAN.

Network layer

Forms the switching/routing layer of the network.

Transport layer

Multiplexes & demultiplexes messages from applications.

Acts as a transparent layer to applications & thus isolates them from the transport system

layers.

Makes & breaks connections for connection-oriented communications.

Controls flow of data in both directions.

Session layer

Establishes & clears sessions for applications, and thus minimizes loss of data

during large data exchange.

Presentation layer

Provides a set of standard protocols so that the display would be transparent to syntax of the

application.

Data encryption & decryption.

Application layer

Provides application-specific protocols for each application & each transport protocol

system.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Figure 11: OSI Communication Architecture

Data Link Layer

The data communication between 2 DTEs is controlled & managed by this layer.
The data communication is a serial bit-oriented stream.
The data link layer needs to do basic functions:

Physical Layer

This is responsible for physically placing the electrical signal on the physical medium &

picking up the signal from it.

This controls & manages the physical & electrical interfaces to the physical medium,

including the connector or transceiver.

The physical medium could be copper, optical fiber or wireless media.
The signal could be either digital or analog.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Figure 13: Sublayers of a Network Layer

Figure 1 4 : Gateway Communication to private subnetworks

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

Presentation Layer

This layer is the medium of presentation of the message's context to the user or application program.

This layer is context sensitive layer.

This can be interpreted as the common languages & image that the users at both end systems use &

understand.

Comparison of OSI and Internet Protocol Layer Models

The transport & network layers form the suite of TCP/IP protocols. The application layers are

combined into application-specific protocols (Figure: 15 ).

In the 7-layered SNA model, the physical, data link & application layers have one-to-one

correspondence with the OSI layers.

Much of the SNA transport & session layer functions equivalent to those of the OSI model are

done in the data flow control & transmission control layers. The combination of these 2 services is

also called the SNA transmission subsystem.

The presentation services, which are known as SNA high level services, combine the

presentation services & functions with some of the session control functions.

Figure 15: Comparison of OSI and Internet Protocol Layers

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

WHAT ARE TOP CHALLENGES IN MANAGING THE NETWORK?

 Analyzing problems, which requires intuition & skill

 Anticipating customers' demands

 Acquiring resources

 Managing the client/server environment

 Networking with emerging technology as part of continuing education

 Collaborative research between academic institutions & industry

 Maintaining reliability

 Diagnosing problems or outrages in a non-disruptive manner

 Estimating value of a technology transition

 Maintaining a secure firewall between the internal network & the Internet

 Sustainable network that is scalable & maintainable

 Staying abreast of the rapid advance of technology

 Determining responsibility for outages to the WAN

Network Management: Goals, Organizations & Functions

This can be defined as OAM&P of network & services.

The goal of network management is to ensure that the users of a network receives the

information technology services with the quality of service that they expect.

Network Management Functions

Network Provisioning

 The engineering group keep track of new technologies & introduces them as needed. (Figure: 17 ).

 Determination of what is needed & when is made through analysis of the traffic and

performance data provided by the network operations.

 Network management tools are helpful to the engineering group in gathering statistics and

studying the trends of traffic patterns for planning purposes.

Network Operations & the NOC

They are concerned with daily operations of the network & providing network services.

Fault Management/Service Restoration

(Check detailed FM in next page).

Trouble Ticket Administration

1) This is the administrative part of fault management & is used to track problems in

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

the network. All problems are to be tracked until resolved.

Configuration Management

2) There are 3 configurations of the network:

1) One is the static configuration & is the permanent configuration of the

network. The static configuration is on that would come up if the network is

started from idle status.

2) The second configuration of a network is the current running configuration.

3) The third configuration is the planned configuration of the future when the

configuration data will change as the network is changed. This information is

useful for planning & inventory management.

Security management

(Check detailed SM in next

page). Performance

Management (Check detailed

PM in next page).

Accounting Management

3) The NOC administers costs & allocates the use of the network.

4) Metrics are established to measure the usage of resources & services.

5) There are 3 classes of reports: systems, management & user.

Network Installation & Maintenance

The network I&M group takes care of all installation & maintenance of equipment & cables.
This group is the service arm of the engineering group for installation & fixing troubles for network

operations.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

or automatically generated by an NMS.

The information on the trouble ticket includes

A tracking number assigned by the system

Time at which problem occurred

Affected user

The nature of the problem

The responsible group/engineer to resolve the problem

The tracking of a trouble involves several groups and the administration of it generally

belongs to the network maintenance group.

Security Management

This involves physically securing network, access to network resources & secured communication

over network.

Access privilege to application software is not the responsibility of the NOC unless the

application is either owned or maintained by the NOC.

A security database is established & maintained by the NOC for access to the network & network

information.

Unauthorized access to the network generates an alarm on the NMS at the NOC.

Firewalls protect corporate networks & network resources from being accessed by unauthorized

personnel & programs including virus programs.

Secured communication prevents tampering of information as it traverses the network, so that

is cannot be accessed or altered by unauthorized personnel. Cryptography plays a vital part in

security management.

Performance Management

This is concerned with the performance behavior of the network.

The NMS measures the traffic and performance of the network and displays its status.

The NOC gathers data & keeps them up to date to tune the network for optimum performance.

The network statistics include data on traffic, network availability& network delay.

The traffic data can be captured based on volume of traffic in the various segments of the network.

Performance data on availability & delay is useful for tuning the network to increase the reliability

& to improve its response time.

Traffic statistics are helpful in detecting trends & planning future needs.

Accounting Management

The NOC administers costs & allocates the use of the network.

Metrics are established to measure the usage of resources & services.

Prepared by: GURUPRASATH V A, AP,CSE Sri Sairam College of Engineering, Anekal.

There are 3 classes of reports: systems, management & user.

System reports are needed for network operations to track the activities. Management reports go to

the management of the network management group to keep them informed about the activities &

performance of the NOC & the network. The user reports are distributed to the users on a periodic

basis to let them know the status of network performance.

Network & System Management

The problem in the application program is a system problem & falls under the category of system

management. On the other hand, the transport problem from the client's workstation to the server

platform is a system problem & falls under network management.

System management is concerned with management of systems & system resources in the

network. Whereas, Network management is concerned with network resources such as hubs,

switches, bridges, routers & gateways, and the connectivity among them via a network.

Network management also addresses end-to-end connectivity between any two processors in the

network. System management also addresses logging & archiving events.

Network Management Dumbbell Architecture

In figure 16 , the messages consist of management information data & management controls.

Application services are the management-related applications such as fault & configuration

management.

The management protocols are CMIP for the OSI model & SNMP for the Internet model.

Transport protocols are first 4 layers of OSI model & TCP/IP over any of first 2 layers of the 7-layer

OSI model.

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NMS-18CS742 VTU Complete Notes

Course: Network Management (18CS742)

27 Documents

Students shared 27 documents in this course

University: Visvesvaraya Technological University

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Regulation – 2018

18CS742 – NETWORK MANAGEMENT

Module – 1

Data Communication & Network Management Overview

Analogy of Telephone Network Management

Why Telephone Network is popular?

The architecture of the Telephone network is hierarchical therefore it is reliable, dependable and hence

provides good Quality of Service(QoS). Because of this reason the need for data or computer

communication network management can be easily explained through an analogy of telephone network

management.

Telephone Network Model

The structure of a telephone network is depicted in the figure 1. Trunk is a logical link between two

switches-and may traverse one or more physical links that is the end office or Class 5. The end office is

the lowest in the hierarchy, is the local switching office. The dedicated link “loop” connects telephone

and the end office. The remaining four higher levels of switches, from Class 4 to Class 1 are tandem or

toll switches carrying toll (long-distance) calls. Now a day due to modern technology these four levels

are merged together and referred to as class 4. A direct trunk connects two end offices, a tall-connecting

trunk connects an end office to any toll office. and a toll trunk connects any two toll offices.

The direct distance dialing (DDD) network, enables the user to dial far-end telephone with

assistance of an operator. It comprises following 3 transmission trunks:

 A direct trunk connects to end offices

 A toll connecting trunk connects an end office to any toll office

 A toll trunk connects any to toll offices

A circuit connection is set up either directly using a local trunk or via the higher level switches & routes.

Primary & secondary routes are already programmed into the switch. If the primary route is

broken or the facilities over the primary route are filled to capacity, an alternative route is

automatically assigned.

Operations support systems ensure the quality of service in the telephone network.

NOCs (Network Operations Center) are available in all regions to monitor the global status of the

network. Hence the NOCs are considered as center of a telephone network operations.