kommunikatsioonivõrkude struktuurid ja teenused · unlicensed mobile access (uma) technology...

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Kommunikatsioonivõrkudestruktuurid ja teenused

IRT0100Loeng 7 S L AK. 15. okt 2008

Avo Otstelekommunikatsiooni õppetool,

TTÜ raadio- ja sidetehnika [email protected]

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Service Level AgreementsA good service level agreement (SLA) should contain the following:• Identify and describe the service• Describe how it is to be measured• Identify acceptable levels of service• Describe reporting relationships• Describe actions to be taken when

service is unsatisfactory• Identify the expiration date, if any• Affix the signatures of the responsible

parties

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Need for in Home/Office

Frightening Complexity for End UsersNew Domain for Providers…

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Integration of services in IPTV

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Internet Content Distribution

C ontent S erver

H N E D

H N E D

H N E D

P 2P C ontent exchange

C ontent G uide S erver

P 2P A uthentication

S erver

P 2P M anagem ent

S erver

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Internet

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TISPAN NGN Architecture

AccessNetwork AttachmentSubsystem

PSTN

Access TransportNetwork Core Transport Network

IMS

IP

(SIP -based)IP Multimedia Subsystem

(Core IMS )

Resource ControlSubsystem

TISPAN xDSL Connectivity Network

PSTN/ISDN emulationSubsystem

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NGN Consumer Access

xDSLEthernet

Home Shopping

Eth.DTV Tuner

Second Line VoIP

ResidentialGateway

Live Content

Video on Demand

Games Console

NotebookNotebookPDAPDA

Bro

adba

nd A

cces

s

Cable

HomeSecurity

Fiber

802.11b/gRouter

Set-top BoxEt

hern

et

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Unlicensed Mobile Access (UMA) technology provides access to GSM and GPRS mobile services over wireless networks based on unlicensed spectrum technologies, e.g.Bluetooth and IEEE 802.11 networks.

By deploying UMA technology, service providers can enable subscribers to roam and perform seamless handovers between cellular networks and public and private unlicensed wireless networks, and to use for instance SIM/AuCauthentication also in the wireless networks, using dual-mode handsets.

Unlicensed Mobile Access (UMA)

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Roaming means that it is possible to use a terminal when moving from one network to another. Additional features (mobility, security) that involve cooperation between network operators or service providers are usually supported, due to roaming agreementsbetween these operators or service providers.

Portability means that it is possible to use a terminal anywhere in a certain network (e.g. WLAN). However, when moving to another network, mobility or security features are not automatically maintained.

Roaming vs. portability

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Terminal vs. personal mobility

Terminal mobility means the ability of the network to locate a mobile terminal, route incoming or outgoing calls (or packet sessions) regardless of the point of attachment to the network, and maintain connections while the terminal moves around in the network.

Personal mobility means that a person can be reached via any one of several terminals (that can be located at different places) using a single address (e.g. SIP address). This concept has not been widely used yet.

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UMA Protocols • UMA is on top of it at the transport

layer (Layer 4) and has its own set of control protocols .

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Cellular /UMA

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Prioriteedid

Im pact

U rgency

P riority

E stim ate

♣ P eople♣ R esources♣ T im e

hig h

m edium

low

hig h m edium low priority

targetresolution

urgent

< 4 hours

high

< 8 hours

m edium

< 10 days

high

< 8 hours

m edium

< 10 days

low

planned

m edium

< 10 days

low

planned

low

planned

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Intsidendi haldus

• Response to the customer must take place within 24 working hours• Plan for resolution will be communicated at the time work begins

Incidents with low impact or where a work-around is easily followed.

Low

• Response to the customer must take place within 24 working hours• Plan for resolution must be developed and communicated within 48

working hours

Incidents that may be impacting work but for which there is a work-around.

Medium

• Response to the customer must take place within 4 working hours• Plan for resolution must be developed and communicated within 8

working hours

Significant incident that is causing work to slow or stop.

High

• Notice of the issue to relevant users and communication of the expected downtime must take place within 1 hour

• Plan for incident resolution must be developed and communicated within 2 hours

Major incident that is affecting a large group of users or critical business processes.

Urgent

Incident Management Service LevelDefinitionPriority

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Intsidendihalduse mõõdikud

99.5% average availability over the measurement period.

Time a service was down in minutes.The time the service is available according to the service hours specified in the service level agreement.

Service Availability

90% of all incidents are resolved by the target resolution time.

Target resolution by priority:• Urgent – 4 hours• High – 8 hours• Medium – 10 days• Low – as plannedExtensions to expected resolution time must be agreed with the customer.

The time that elapses between acknowledged receipt of an incident and incident resolution. When the incident occurs during scheduled downtime, resolution times will start from the end of downtime.

Incident Resolution Time

Service Level is met 90% of the time.

An incident must be acknowledged and an incident resolution plan communicated within:Urgent: response = 1 hour / plan = 2 hoursHigh: response = 4 hours / plan = 8 hoursMedium: response = 24 hours / plan = 48 hoursLow: response = 24 hours / plan = when work begins

The time it takes IT Services to acknowledge receipt of an incident and communicate a problem resolution plan. Incident response time is Tracked by tier (1-3).

Incident Response Time

TargetMeasureDescriptionCategory

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Sisenemise/väljumise kriteeriumid

ENTRY CRITERIA

• Incident report• Service request

EXIT CRITERIA

• Incident has been resolved to customer’s satisfaction

• Help Desk ticket has been updated and closed

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Introduction to ITIL• ITIL – Information Technology

Infrastructure Library• Developed by the Office for Government

Commerce (OGC) in England• Best practices focused on the management

of IT service processes • Open source

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ITIL Service Management (ITSM)Two main components:• Service Support – five processes that provide

support for day-to-day operation of IT services• Service Delivery – five processes that focus on

long-term planning and improvement of IT services

These two components are linked together through the Service Desk – a function that provides a single point of contact that focuses on rapid restoration of normal service operations to users

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ITIL Service Management

Service Level Management

FinancialManagementAvailability

Management

IT Service ContinuityManagement

Capacity Management

ServiceDelivery

Service Desk

Change Management

ReleaseManagementIncident

Management

Configuration Management

Problem Management

ServiceSupport

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Help Desk Tools

• ACD Automated Call Distribution• CTI Computer-to-Telephony Integration• Integration with CRM Customer Relationship

Management• FAQs: Frequently Asked Questions• Self-diagnosis tools: end user can analyze cause of

problem with ability to offer solutions• Software Deployment (SD) for managing desktops

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VoIP probleemid• Lack of continuous service during a power outage TOIDE• Emergency calls (112) (Problem of locating call) • Sound quality and reliability KVALITEET• Vulnerable to same attacks as IP data networks IP OHUD

– Denial of Service (DOS)– Viruses– Worms– Port scanning

• Vulnerable to spam (Spam over Internet Telephony)• Toll fraud (Call spoofing)

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Hajuspaigutus ja VoIP

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Kõnede tagamine

IP Network

Multimedia PC

Multimedia PC

PC to PC over internet

PSTN

Gateway

PSTN

Gateway

Public Switched Telephone Network

Gateways allow PCs to also reach phones

Telefonilt…telefonile

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VoIP lahendusi

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VoIP probleemid• Lack of continuous service during a power outage TOIDE• Emergency calls (112) (Problem of locating call) • Sound quality and reliability KVALITEET• Vulnerable to same attacks as IP data networks IP OHUD

– Denial of Service (DOS)– Viruses– Worms– Port scanning

• Vulnerable to spam (Spam over Internet Telephony)• Toll fraud (Call spoofing)

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(a) A switch provides the network to a cluster of users, e.g. a telephone switch connects a local community

(b) A multiplexer connects two access networks, e.g. a high speed line connects two switches

Access network

Network

Kokkuühendamine

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12

3

4567

Trun

k nu

mbe

r

N(t)

t

All trunks busy, new call requests blocked

Sõlmedevahelised kanalid

Number of busy trunks

activeactive

active

activeactiveactive

activeactive

activeactive

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Lingid (1)http://en.wikipedia.org/wiki/Voice_over_Internet_Protocolhttp://en.wikipedia.org/wiki/Mobile_VoIPhttp://www.umatoday.com/http://en.wikipedia.org/wiki/Generic_access_networkhttp://www.dafocus.com/http://www.t-

mobile.com/company/PressReleases_Article.aspx?assetName=Prs_Prs_20070627&title=T-Mobile%20Introduces%20Unlimited%20Calling%20Over%20Wi-Fi%20With%20the%20National%20Launch%20of%20T-Mobile%20HotSpot%20@Home

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Lingid (2)http://www.nokia.com/A4136001?newsid=1066083

http://www.ouka.fi/wirelesscities/Presentations/20060607_UMA_Wireless_Cities_Seminar.ppt

http://www.thefmca.com/

http://www.nextgenweb.org/wp-content/uploads/2008/06/fcc-fifth-report.pdf

http://www.canadanewswire.ca/en/releases/archive/October2007/31/c2140.html

kommunikatsioonivõrkude struktuurid ja teenused · unlicensed mobile access (uma) technology...

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