MJ01/0704 1

Session 01

Network Overview

MJ01/0704 2

Data and Telecommunication Network

Terminal

Modem

Voice

Terminal

Modem Modem

Voice

Host

Data communication network

Telecommunication network

MJ01/0704 3

Data and Telecommunication Network

• Computer data is carried over long distance by telecommunication network

• Output of telephone is analog and output ofcomputers is digital

• Modem is used to modulate and demodulate computer data to analog format and back

• Clear distinction between the two networks is getting fuzzier with modern multimedia networks

MJ01/0704 4

Telephone Network

• Characteristics:• Reliable - does what is expected of it• Dependable - always there when you need it • Good quality (connection) - hearing each other well

•Reasons:

• Good planning, design, and implementation• Good operation and management of network

• Automatic routing• Fault management• Use of Operations Systems to ensure QoS

MJ01/0704 5

Operations Systems / NOC

• Monitor telephone network parameters• S/N ratio, transmission loss, call blockage, etc.

• Real-time management of network• Trunk (logical entity between switches) maintenance

system measures loss and S/N. Trunks not meeting QoS are removed before customer notices poor quality

• Traffic measurement systems measure call blockage. Keep the call blockage below acceptable level

• Operations systems are distributed at central offices• Network management done centrally from Network

Operations Center (NOC)

MJ01/0704 6

IBM SNA Architecture

Mainframe

Communination Controller

Communication Controller

Cluster Controller

Cluster Controller

Workstation Workstation

• IBM System Network Architecture (SNA) is a major step in network architecture

• SNA is based on multitude of (dumb) terminals accessing a mainframe host at a remote location

MJ01/0704 7

Distributed Computing Environment

Ethernet

Workstation

Workstation

Host

Host

Workstation

Hosts and Workstations on LAN

• Driving technologies for DCE:• Desktop processor• LAN• LAN - WAN network

MJ01/0704 8

LAN-WAN Network

LAN A LAN B

LAN C

Bridge /Router

Bridge /Router

Bridge /Router

WANcommunication link

• Major impacts of DCE:• No more monopolistic service provider• No centralized IT controller• Hosts doing specialized function• Client/Server architecture formed the core of DCE network

MJ01/0704 9

Client/Server Model

• Client always initiates requests• Server always responds• Notice that control is handed over to the receiving entity.

Client Server

Control Transfer

Simple Client-Server Model

Request

Response

Control Transfer

MJ01/0704 10

TCP/IP Based Networks

• TCP/IP is a suite of protocols• Internet is based on TCP/IP• IP is Internet protocol at the network layer level• TCP is connection-oriented transport protocol and

ensures end-to-end connection• UDP is connectionless transport protocol and

provides datagram service• Internet e-mail and much of the network mgmt.

messages are based on UDP/IP• ICMP part of TCP/IP suite

MJ01/0704 11

Internet Configuration

LAN A LAN B

LAN C

Router

Router

Router

LAN Y LAN Z

LAN X

Router

Router Router

WAN

Workstation

Mail Server

Mail Server Workstation

Gateway

Gateway

DomainNameServer

Workstation

PC

MJ01/0704 12

SNA, OSI, and Internet

Application

Presentation

Session

Transport

Network

SNICP

SNDCP

SNDAP

Data Link

Physical

Application Specific

Protocols

Transport

Network

IP

Not SpecifiedPhysical

Data Link

Path Control

Transmission Control

Data Flow Control

Presentation

End User Application

SNA OSI INTERNET

• Similarity between SNA and OSI• Simplicity of Internet; specifies only layers 3 and 4• Integrated application layers over Internet• Commonality of layers 1 and 2 - IEEE standard

MJ01/0704 13

Architecture, Protocols and Standards

• Communication architecture• Modeling of communication systems, comprising

• functional components and• operations interfaces between them

• Communication protocols• Operational procedures

• intra- and inter-modules• Communication standards

• Agreement between manufacturers on protocols of communication equipment on

• physical characteristics and • operational procedures

MJ01/0704 14

Communication Architecture

User A

Application Layers

Transport Layers

User Z

Application Layers

Transport Layers

Physical Medium

Peer-Protocol Interface

Direct Communication between End Systems

User A

Application Layers

Transport Layers

User Z

Application Layers

Transport Layers

Physical Medium

Peer-Protocol Interface

Communication between End Systems via an Intermediate System

Transport Layer

Conversion

System A Intermediate system System Z

Physical Medium

MJ01/0704 15

Communication Architecture

• Inter-layer interface: user and service provider• Peer-layer protocol interface • Role of intermediate systems

• Gateway: Router with protocol conversion as gateway to an autonomous network or subnet

MJ01/0704 16

Application Protocols

OSI User

VT

FTAM

MOTIS

CMIP

Presentation Layer

SNMPSMTP

FTP File Transfer

Mail Transfer

Terminal Applications

Management Applicationst

Transport Layer

TELNET

Internet User

Internet userTelnetFile Transfer ProtocolSimple Mail Transfer ProtocolSimple Network Management Protocol

OSI userVirtual TerminalFile Transfer Access & MgmtMessage-oriented Text Interchange StandardCommon Management Information Protocol

MJ01/0704 17

Common Network Problems

• Loss of connectivity

• Duplicate IP address

• Intermittent problems

• Network configuration issues

• Non-problems

• Performance problems

MJ01/0704 18

Network Management

Network

Management

NetworkProvisioning

Network Operations

NetworkMaintenance

Planning

Design

Fault Management

Trouble TicketAdministration

Network Installation

Network Repairs

Facilities Installation& Maintenance

Routine NetworkTests

Fault Management / Service Restoration

Configuration Management

Performance Management / Traffic Management

Security Management

Accounting Management

Reports Management

Inventory Management

Data Gathering & Analyses• OAM&P• Operations• Administration • Maintenance• Provisioning

MJ01/0704 19

NM Functional Flow Chart

Engineering Group- Network Planning &

Design

Operations Group NOC

- Network Operations

I & M Group

-Network Installation &Maintenance

Fault TT

Configuration Data

TTRestoratio

n

Performance & Traffic Data

Installation

NewTechnology

Network

Users

ManagementDecision

MJ01/0704 20

NM Components

NMS

NetworkAgent

NetworkAgent

NetworkObjects

NetworkObjects

MJ01/0704 21

Interoperability

NMSVendor A

NetworkAgent

NetworkAgent

NetworkObjects

NetworkObjects

NMSVendor B

NetworkAgent

NetworkAgent

NetworkObjects

NetworkObjects

Messages

Services & Protocols

• Message exchange between NMSs managing different domains

MJ01/0704 22

Status and Future Trends

• Status: • SNMP management• Limited CMIP management• Operations systems• Polled systems

• Future trends:• Object-oriented approach• Service and policy management • Business management• Web-based management

MJ01/0704 23

Challenges of IT Managers

• Reliability• Non-real time problems• Rapid technological advance• Managing client/server environment• Scalability• Troubleshooting tools and systems• Trouble prediction• Standardization of operations - NMS helps• Centralized management vs “sneaker-net”