Chapter 1Data CommunicationsandNM Overview

Outline

• Analogy of telephone network• Data and telecommunication network• Distributed computing environment• Internet• Protocols and standards• IT management• Network and system management• Current status and future of network management

Telephone Network

• Characteristics:• Reliable - does what is expected of it• Dependable - always there when you need

it (remember 911?)• Good quality (connection) - hearing each

other well• Reasons:

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

network

Telephone Network Model

Regional CenterClass 1 switch

Sectional CenterClass 2 switch

Primary CenterClass 3 switch

Toll CenterClass 4 switch

End OfficeClass 5 switch

Regional CenterClass 1 switch

Sectional CenterClass 2 switch

Primary CenterClass 3 switch

Toll CenterClass 4 switch

End OfficeClass 5 switch

Voice Voice

To otherRegional centersSectional centersPrimary centersToll centersEnd offices

To otherPrimary centersToll centersEnd offices

To otherClass 4 toll pointsEnd offices

Figure 1.1 Telephone Network Model

Legend:Loop

Direct Trunk

Toll-Connecting Trunk

Toll Trunk

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. Additional switch planned to keep the call blockage below acceptable level

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

Operations Center (NOC)

Data and Telecommunication Network

Terminal

Modem

Voice

Terminal

Modem Modem

Voice

Host

Data communication network

Telecommunication network

Figure 1.3 Data and Telecommunication Networks

Loop Loop Loop

IBM SNA Architecture

Mainframe

Communicationscontroller

Communicationscontroller

Clustercontroller

Clustercontroller

Figure 1.5 IBM Systems Network Architecture Model

Workstation Workstation

DCE with LANDCE.. Distributed Computing Environment

Ethernet

Workstation

Workstation

Host

Host

Workstation

(a) Hosts and Workstations on Local LAN

LAN-WAN Network

LAN A LAN B

LAN C

Bridge /Router

Bridge /Router

Bridge /Router

WANcommunication link

Client/Server Model

Client Server

Controltransfer

Controltransfer

Figure 1.7 Simple Client-Server Model

Request

Response

Client/Server Examples

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

InternetConfiguration

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

Communication Architecture

OSI Reference Model

OS

I Lay

ers

and

Ser

vice

s

PDU Communication Model

PDU: Protocol Data UnitPCI: Protocol Control InformationUD: User Data

PDU = PCI + UDUDn = PDUn+1

Gateway

DTE : Data Terminating Equipment

T

N

DP

SNA, OSI, and Internet

Application Protocols

NM Case HistoriesNM Case Histories

Common Network Problems

• Loss of connectivity (Link, Node, Interface)

• Duplicate IP address (Procedural)• Intermittent problems• Network configuration issues• Non-problems• Performance problems

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”

Please refer to Sec. 1.7 for more details

Network Management (NM)

Definition OAM&P of Network and Services OAM&P: Operations, Administration,

maintenance, and Provisioning) Goal

To ensure that the users of a network receive the IT services with the quality of service (QoS) that they expect.

Top-down View of NM functionsNetwork

Management

NetworkProvisioning

Network Operations

NetworkMaintenance

Planning

Design

Fault Management

Trouble Ticket

Administration

Network Installation

Network Repairs

Facilities Installation

& Maintenance

Routine Network

Tests

Fault Management / Service Restoration

Configuration Management

Performance Management / Traffic Management

Security Management

Accounting Management

Reports Management

Inventory Management

Data Gathering & Analyses

Figure 1.21 Network Management Functional Groupings

NM Functional Flow Chart

NOC: Network Operation Center

I&M: Installation & Maintenance

TTTrouble Ticket

網管五大管理功能領域 管理功能領域 (Management Functional

Areas, MFAs) 障礙管理 (Fault Management) 組態管理 (Configuration Management) 安全管理 (Security Management) 效能管理 (Performance Management) 計量管理 (Accounting Management)

ITU-T X.700ITU-T X.700

障礙管理 (Fault Management)

Fault Management (FM) Detection of a problem, fault

isolation and correction to normal operation.

FM involves the following steps: Discover the problem. Isolate the problem Fix the problem (if possible) Use of Trouble-Ticket Systems

障礙管理之功能 Maintain and examine error logs Accept and act upon error detection

notifications Trace and identify faults Carry out sequences of diagnostic

tests Correct faults

障礙管理實例

InternetInternet

RMONDevice

UNIX....

FDDI

UNIX PC

Firewall/ Router ....

...

....

...

PC UNIX

PC

UserUser DNS

MailServer

WWWServer

FM 例子：障礙存錄

組態管理 (Configuration Management)

Configuration Management (CM) The process of finding and setting up

(configuring) network devices.

CM identifies, exercises control over, collects data from, and provides data to networked systems.

組態管理之功能 Set the parameters that control the routine

operation of the networked system. Associate names with managed objects and

sets of managed objects. Initialize and close down managed objects. Collect information on demand about the

current condition of the networked system. Obtain announcements of significant

changes in the condition of the networked system.

Change the configuration of the networked system.

CM 例子 : Auto Discovery

CM 實例 : 中華電信(CHTNet)

安全管理 (Security Management)

Security Management (SM) The process of controlling access to

information on the networked system. 安全管理之功能

The creation, deletion, and control of security services and mechanisms.

The distribution of security-relevant information.

The reporting of security-relevant events.

效能管理 (Performance Management)

Performance Management (PM) Measuring the performance of network

hardware, software, and media. 幾個量測例子：

Overall throughput Percentage utilization Error rate Response time

效能管理之功能 Gather statistical information. Maintain and examine logs of

system state histories. Determine system performance

under natural and artificial conditions.

Alter system modes of operation for the purpose of conducting PM activities.

PM例子|網路訊務量監測

計量管理 (Accounting Management)

Accounting Management (AM) Tracking each individual and group

user's utilization of network resources to better ensure that users have sufficient resources.

AM enables charges to be established for the use of network resources, and the costs to be identified for the use of those network resources.

計量管理之功能 Inform users of costs incurred or

resources consumed. Enable accounting limits to be set

and tariff schedules to be associated with the use of resources.

Enable costs to be combined where multiple resources are invoked to achieve a given communication objective.

NM Components

Interoperability

NMSVendor A

NetworkAgent

NetworkAgent

NetworkObjects

NetworkObjects

NMSVendor B

NetworkAgent

NetworkAgent

NetworkObjects

NetworkObjects

Messages

Services & Protocols

Interoperability (cont.)

Services & Protocols

Network Management Model

Legend ：MA: Manager ApplicationsMO: Managed Objects

R: Real Resource

Network Network

AgentAgent

R

Communication Protocols

ManagerManager

MAMAManagement Management OperationOperation

ResponResponseseEvenEven

tt

Communication Protocols

MOMO

ManagementStation

NetworkElement

網路管理構成元素 管理者 (Manager) 代理者 (Agent) 網路管理通信協定 (Network

Management Protocol) 網路管理資訊 (Network Management

Information)

網路管理角色 管理者 (Manager)

執行各項用來監督 (Monitor) 及控制(Control) 網路設備的網管應用程式

代理者 (Agent) 位於網路設備端，負責接受從管理者端送來之

要求，執行所付予之工作，並將結果回報給管理者。

網路管理協定 網路管理協定專為管理者與代理者所設計之通信協

定。 網路管理協定提供管理者與代理者間交換網管資訊

標準方式。 目前主要兩種網管通信協定

Internet 網管通信協定： SNMP (Simple Network Management)

OSI 網管通信協定： CMIS/P (Common Management Information Service /

Protocol)

網路管理資訊 被管物件 (Managed Object, MO)

將待管之網路資源，抽象化為物件，稱被管物件，簡寫 MO 。

被管物件所代表之網路資源可大可小，大可至代表整個網路設備如 ATM 交換器，小可至代表某一網路元件之參數，如介面卡之狀態。

管理資訊庫 (Management Information Base) 被管物件之集合，簡寫 MIB 。

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

管理金字塔 (Management Pyramid)

Business ManagementBusiness Management

Customer ManagementCustomer Management

Service ManagementService Management

Distributed System ManagementDistributed System Management

Network ManagementNetwork Management

Element ManagementElement Management

Network Management

System Management

Applications Management

Service Management

Eneterprise Management

Data

Voice

Video

Multimedia

LANMAN

WANCorporate Network

VPNIN

Configuration

Performance

Accounting

Fault

Accounting

Planning

Installation

Operation

Change

Network TypesNetwork TypesNetwork TypesNetwork Types

Functional AreasFunctional AreasFunctional AreasFunctional Areas

StagesStagesStagesStages

Information TypesInformation TypesInformation TypesInformation TypesDisciplinesDisciplinesDisciplinesDisciplines

管理範圍 管理範圍 ??

網路管理基本方式

InternetInternet

RMONDevice

UNIX....

FDDI

UNIX PC

Firewall/ Router

網管系統網管系統網管系統網管系統

.......

PollingPolling NotificationNotification

....

...

PC UNIX

PC

NMNMNMNM

network

RMONRMONDeviceDevice

網路管理基本方式 ( 續 ) Polling ( 輪詢 )

網管系統主動至被管設備要求網管相關資訊 。 一般採用週期性輪詢，週期長短視需要而定，一

般設為 5~15 分鐘。 Notification ( 通報 )

網路設備自行發現問題時，主動向網管系統發出事件報告 (Event Report) 。