2110 slides1 10.ppt

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TelcomTelcom 2110 Network Design2110 Network Design

David TipperAssociate ProfessorAssociate Professor

Department of Information Science and Telecommunications

University of Pittsburghy g

[email protected]@tele.pitt.edu

http://www.sis.pitt.edu/~dtipper/tipper.htmlSlides 1Slides 1

http://www.sis.pitt.edu/~dtipper/2110.html

Course Outline

• Introduction – Class Organization, network design types, top-down design

• Requirements and Planning• Requirements and Planning – Technical Goals and Constraints

– Economics and Technology Choices

– Traffic Demand Modeling and capacity requirements

• Network Design Modeling and Algorithms

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– Relevant Results from Graph Theory

– Relevant Results from Optimization Theory

– Heuristics

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Course Outline

• Access Network Design

– Topology algorithms, physical design

– Wireless access network design– Wireless access network design

• Wide Area Network Design

– Design Algorithms

– Virtual network design

– Fault Tolerance/Survivability/Availability

• Metro Network Design

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Metro Network Design

– Technology and Design algorithms

• Emerging Issues

– Support for Smart Grid

– Energy Efficiency

Network Design

• A “Network” can be thought as – Electronic communication devices

• PCs phones PDAs laptops etc• PCs, phones, PDAs, laptops, etc.

– Network Devices • (hubs, routers, cross-connects, base stations, etc..)

– Communication links• (Coax cable, 10base T, T1, T3, OC1, wireless, GPON, etc.)

– Services• Phone calls video web software applications etc

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Phone calls, video, web, software applications, etc.

• Network Design– Determines the location and type of network devices,

the types and size of communication links to provide services to the electronic communication devices.

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Network Design, Performance and Management

traffic data

Forecast adjustment,Marketing input

Network (IP, circuit-switched, wireless)

various controls

routing update

capacity change

traffic data

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Real-Time Traffic Management

Network Design/Planning

Capacity Management, Traffic Engineering, VPN Design

secs-mins

days-weeks

months-years

Network Time Scales

Short Term Planning Medium Term Planning Long Term Planning

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Long Term Planning 3-5 years typically• How many $ are needed to get a usable network?• What sort of network performance can we get with Y

$

Network Design Issues

additional $?• What should our network look like?• What Technology should be used?• What layer should provide protection?

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• Can classify network design problems in several ways one method is based on geographical size 1. Access Networks

Types of Network Design

1. Access Networks • LANs, Campus, Residential networks, Cellular networks, etc

2. Metropolitan Networks (Metro Nets)• Interconnection of central offices, POPs, corporate locations in

a city, campus backbone network• Higher bandwidth, may include leased lines

3. Wide Area Networks (WANs) or Long Haul NetworksP i t d P bli B kb t k (UUNET AT&T)

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• Private and Public Backbone networks (UUNET, AT&T)• Interexchange Carriers• Corporate virtual private network over common infrastructure

• Note, that the network design techniques for each category may differ

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Access, Metro and Long-Haul Transport

WAN Long-haul network

Access network

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Metro networkSource: J. Doucette, Ph.D. Thesis, UofA, 2004

Access, Metro and WANs

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Source: W. D. Grover, ECE 681, UofA, Fall 2004Partitioned-Heirarchical view of a network.

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Typical Wired Network Structure

Metro Area 2Metro Area 1

Backbone

Access

Feeder Network

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Central Offices

Metro Area 3

Metro Area n

Current TrendsCore ~ MeshMetro ~ RingAccess ~ Tree

Transmission Rates

Access POTS Line <64 KbpsT1 1.5 MbpsDSL .5 – 10MbpsDSL .5 10MbpsCable 3-10 MbpsFTTH/FTTC 10Mbps – 2.5GbpsCellular 384Kbps – 10Mbps

MetroT3 44.736 MbpsOC-1 51 MbpsOC-3 155 MbpsOC-12 622 Mbps

Rates increase from

access to WAN

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pOC-48 2.5 GbpsOC-192 10 Gbps

WANOC-192 10GbpsOC-768 40 GbpsDWDM 1.6Tbps – 10Tbps

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• Airline inter-hub analogy:– A traveler from Pittsburgh needs to visit Naples, Italy.– An airport shuttle collects people going to the airport

Access, Metro and Long-Haul/WAN: Roles and Analogy

An airport shuttle collects people going to the airport.– A regional “commuter” jet brings him/her to JFK airport in New York

City.– At NYC, people from all over East Cost to board a well-filled 747 non-

stop to Rome, Italy– From Rome, a regional jet takes him/her to Naples– Airport shuttle drops travelers at their hotels in Naples

• The pattern is: access - transport - access• An OC n or a DWDM wavelength is the “747”

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• An OC-n or a DWDM wavelength is the 747• multiplexing and grooming in the access and metro transport stages

(switches, routers, ATM service nodes) are the regional airlines.• Efficient solutions in airlines, shipping, and telecommunications

industry all have this basic repeated structure.

Network Technology

Networks have varying technology, components and protocols depending on size

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ACCESS: Twisted pair, T1, DSL, Cable Modem, WLAN, cellular, Fiber to Curb , Ethernet, etc.

METRO: SONET, ATM, MPLS, Carrier Ethernet, Frame Relay, WiMAX, point to point microwave, free space optical, etc

WAN: Cross connects, routers, etc, DWDM, MPLS, IP, etc, SIP, BGP, OSPF etc,

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• Can also classify network design problems based on technology used– Wired vs Wireless


– Wired vs. Wireless– Circuit switched vs. packet switched– Etc.– For example corporate access network

• Wired LAN vs Wireless LAN

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Vs.

LAN vs. WLAN Design

-80 dBm

• LAN Design: selection of technology (e.g., 100 Mbps vs. 1 Gbps vs. 10Gbps Ethernet) and cabling (e g coax twisted pair optical; plenum vs

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(e.g., coax, twisted pair, optical; plenum vs. nonplenum).

• WLAN Design selection of technology (e.g.,11Mbps 802.11 b , 54Mbps 802.11g, 106Mbps 802.11n) and AP Placement based on

• Signal coverage and capacity• Power level and access to AC power• Frequency channel selection• Connection to wired infrastructure

– Take measurements to get signal quality map

-80 dBm

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• Can classify network design problems based on network state

1 G fi ld N k D i


1. Greenfield Network Design • build a new network from scratch

2. Incremental Network design• Re-engineering a network

– Upgrade/change technology – increase capacity

– Improve fault tolerance, performance, etc.

N t k i d i

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• Network expansion design– Add users/facilities to a network

3. Virtual Network Design– Build an overlay network on top of a existing physical network

infrastructure – short lived compared to physical network design

– Ethernet VLANs, IP/MPLS VPNs, CDNs, etc.

Greenfield Example

BS3

BS4

BS5

BS4

Want to build a cellular network to cover a small city.

BS7

BS2

BS4

BS1

BS3

BS1

BS3

BS4

IBM

MSC

BS7 BS5

BS2

BS3

BS4

BS1

BS6

BS2

BS3

BS4

BS1

Base stations (BS) locations determined by radio coverage

Need to determine locations of BSC and

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SD

Centillion 1400BayNetworks

ETHER RS232C

PC CARD

P*8x50OOO130AON6

INS ACT ALMRST LINK

PWR AL M F AN0 FAN1 PWR0 PWR1

ALM

BSC

SD

Centillion 1400Bay Networks

ET HER RS 232C

PC CARD

P*8x50OOO1 30A O N6

INS ACT ALMRST LINK

PWR ALM F AN0 FAN1 PWR0 PWR1

ALM

BSC

SD

Centillion1400BayNetworks

ET HER RS232C

PCCARD

P*8x50OOO1 30AO N6

INS ACT ALMRST LINK

PWR ALM F AN0 FAN1 PWR0 PWR1

ALM

BSC

SD

Centillion1400BayNetworks

ETHER RS232C

PCCARD

P*8x50OOO130AON6

INS ACT ALMRST LINK

PWR AL M F AN0 FAN1 PWR0 PWR1

ALM

BSC

BS2

BS7

BS5

BS7 BS5

BS6BS6

BS1

30 BS, 4 BSC

interconnect base stations to a BSC then to the MSC

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Example

BS3BS5

BS4

Minimum-cost network design

BS2

BS7

BS2

BS4

BS1

BS3

BS1

BS3

BS4

IBM

MSC

BS7 BS5

BS2

BS3

BS4

BS1

BS6

BS2

BS3

BS4

BS1

BS1

SD

Centillio n1400BayNetworks

ETHE R RS 232C

PC CAR D

P*8x50

OOO130A O N6

INS ACT ALMR ST

LIN K

PWR ALM FAN 0 FAN 1 PWR0 PWR1

ALM

BSC

SD


ETHE R RS 232C

PC CAR D

P*8x50

OOO130A O N6

INS ACT ALMR ST LIN K


ALM

BSC

SD


ETHE R RS 232C

PC CAR D

P*8x50

OOO130A O N6

INS ACT ALMR ST LIN K


ALM

BSC

SD


ETHE R RS 232C

PC CAR D

P*8x50

OOO130A O N6

INS ACT ALMR ST

LIN K


ALM

BSC

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BS7

BS5

BS7 BS5

BS6BS6

30 BS, 4 BSC

Incremental Design Example

BS3BS5

BS4

Given Topology how do you make it single link fault tolerant

BS2

BS7

BS2

BS4

BS1

BS3

BS1

BS3

BS4

IBM

MSC

BS7 BS5

BS2

BS3

BS4

BS1

BS6

BS7 BS5

BS2

BS3

BS4

BS1

BS1

SD

Centillion1400Bay Networks

ETHER RS 232C

PCCARD

P* 8x50

OO O130AO N

6

I NS ACT ALMRST LINK

PWR ALM FAN0 FAN1 PWR0 PW R1

ALM

BSC

SD


ETHER RS 232C

PCCARD

P* 8x50

OO O130AO N

6



ALM

BSC

SD


ETHER RS 232C

PCCARD

P* 8x50

OO O130AO N

6



ALM

BSC

SD


ETHER RS 232C

PCCARD

P* 8x50

OO O130AO N

6



ALM

BSC

Mesh-restoration network design

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BS7

BS5

BS7 BS5

BS6BS6

30 BS, 4 BSC Backup link

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Virtual Network Design

Provider Edge (PE) Router

Provider Core Router C

OverlayVPN Network

Label Switch Path (LSP)

A

B

C

2

1

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Service ProviderCore Network 53

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2

Taxonomy

• The various network design classifications can be combined

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless. . . . . . . . . .

Technology

Stage

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Virtual. . . . . . . . . .

greenfield greenfield incremental

Stage

For example may have a wireless incremental access network design problemThe techniques used to design the network will depend on the classification

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• Computer Aided Design Tools available for certain problems– Aimed at Metro, Backbone and Wireless Access Network Design

Network Design Tools

Aimed at Metro, Backbone and Wireless Access Network Design

– User provides set of traffic demands, geographic locations, performance requirements, etc.

– Most use some sort of optimization based formulation with heuristic solution to minimize $

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• Variety of tools available- many are internal vendor or consultant tools - Examples– OnePlan by VPISystems (wired networks)

Network Design Tools

OnePlan by VPISystems (wired networks)

– SP-Guru by OPNET (wired networks)

– ETX by ETX (Cellular Networks)

– CellPlan – by CellCAD (Cellular Networks) etc.

– WLAN Planner by Motorola

• Some link to simulation packages – can verify design performance

• Provide Costing, tariff calculations, visualization, etc.

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Wireless Design Tools

Wireless Design Tools Concentrate on base station/AP placement and radio signal coverage, not backhaul design

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Indoor Models Indoor Models

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WLANS Design Tools

• Motorola LAN Planner

• Lucent: WiSE tool• Lucent: WiSE tool

• Given building/space to be covered and parameters of building and AP –predicts signal

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predicts signal coverage

• Regardless of network design problem type, can follow a top down network design approachA t d t k d i j t h ld f ll

Top Down Network Design Approach

A top down network design project should follow the four steps below: – Conceptual Model

• Objectives, Requirements, Constraints

– Logical Model• Technology, network graph, node location, link size, etc.

(where algorithms are used to minimize cost)

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(where algorithms are used to minimize cost)

– Physical Model• Specific hardware/software implementations • (e.g., wiring diagram, repeater locations, etc.)

– Implementation, Testing, Tuning and Documentation

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• Determining Objectives– Try to understand the customer’s business

Conceptual Model Design

• industry, market, suppliers, product, the competition they face, etc.

– Try to understand the organizational structure of the business, their separate departments, lines of business, remote

ffi t

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offices, etc.

• Identify Business Objectives of the project– Through surveys/questionnaires, meetings

Business Goals

• Identify overall business goal of network– What will the network be used for? Mission critical uses?– How does the customer think the new network will improve their p

business practices?– What is the criteria to be used to judge the network success/failure?

• Typical business goals (may not be realistic!)– Increase revenue and profit– Shorten product development cycles/improve corporate

communications

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communications– Provide new services/Modernize out-dated technologies– Reduce network costs– Make more data available to more people– Improve network security and reliability

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Business Constraints

• Organizational Politics and Policies– Who will manage/run network

What are the companies policy on suppliers– What are the companies policy on suppliers, platforms, vendors etc.

– Open vs. proprietary solutions?– Security issues

• Budget and Staffing Constraints– Your design must fit the budget– Staff abilities may determine some of your design

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Staff abilities may determine some of your design– Is a business case/life cycle cost analysis needed?

• Scheduling – Timeline, milestones

Technical Goals & Constraints

• From surveys/questionnaires, meetings etc. application data determine technical goals and constraints

• Need to determine the technical scope of the project j(i.e., the network design problem classification) – Network Size

• (LAN, Campus net, enterprise WAN, backbone, etc.)• Sites to be connected, distances, etc.

– Network Technology requirements/goals• Wired vs. wireless, etc.

– Network lifecycle state• Greenfield, incremental, VPN

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, ,

• Technical goal is to build a network that meets user’s requirements + some they may not know they need.

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Technical Goals & Constraints

• Typical Technical Goals – Scalabilityy

– Availability

– Network Performance• Utilization, Throughput, Delay, Delay Jitter, Packet

Loss, Call blocking, etc.

– Security

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Security

– Manageability/Interoperability

– Affordability $$

Technical Goals - Continued

• Traffic estimation is crucial to determine many network performance requirements

What are current/existing networks and services– What are current/existing networks and services– Identify applications and services to be provided from

surveys and meetings– Need to estimate application characteristics– As a guideline construct a table with the following

info

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ApplicationType of Application

New App?

Freq of use Criticality Data Rate Perf. Metric

Sales Tracking

Distributed client/server

No/hourly Very Bursty/ Max .5Mbps – mean ~100Kbps

Delay

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Conceptual Model Network Design

• Conceptual Model Design

• At end of conceptual model design should have gathered/identified

• Objectives– Business Goals (e.g., make sales force more responsive to

customers on sales calls)

– Technical Goals (e.g., provide wireless access to corporate data to sales force)

• Requirements

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Requirements– Business (e.g.,support XYZ application)

– Technical (availability, delay, bandwidth, etc.,)

• Constraints – Business (organizational, budget, etc.,)

– Technical (vendor, technology, sites to connect, security,etc.)

• Translate Conceptual Level Goals and requirements into Logical Level design

What kind of network will meet the conceptual design

Logical Level Network Design

– What kind of network will meet the conceptual design based on the information gathered.

– Topological network design (may use math algorithm here!)

• Technology selection• Costing • Performance tradeoffs

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• Need for sub-netting • addressing issues• etc.

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• Typically many alternate logical designs are feasible• Rank based on attributes

C t

Logical Level Network Design

– Cost– Performance

• Delay, throughput,call blocking, availability, etc.

– Scalability– Management– Maintenance– Utilization

Et

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– Etc.

• May ask managers to evaluate tradeoffs– One approach is assume 100 point to be distributed among

the categories of interest and managers must allocate the points among the attributes

• Hardware level requirements– Specific Router performance based on bandwidth

i

Physical Level Network Design

requirements

– Switches, Repeaters, etc...

• Equipment location requirements– Physical security requirements

– Electrical Power

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• Capacity and Media selection– Bandwidth required, coax, fiber, etc.

– Wiring diagrams

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Testing, Tuning and Documentation

• Finally Step in Network Design– Write and implement a test plan to show p p

network meets technical goals/requirements

– Tune network/application parameters to improve performance (e.g., adjust active queue management thresholds in route to improve packet loss)

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– Document Design

Summary

• Network Design is not a precise science.– Many different types of problems

• e g greenfield vs incremental wired vs wirelesse.g., greenfield vs. incremental, wired vs. wireless

– There can be several good answers (many more bad ones!) - usually no one best solution.

– It involves trade-offs among cost vs. performance, technical vs. non-technical issues

• Top Down Design approach useful as a framework• In many network designs (WAN Metro) use

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• In many network designs (WAN, Metro) use mathematics/algorithms to help designers identify good solutions– Use computer models to solve mathematical

formulations when possible

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