Ascend

Ascend Communications

Extending the Internetto Meet Your Needs

2

Who Uses the Internet?

Mobile

SmallOffice

Remote Office

Corporate Enterprise

Backbone ISP POPSOHO

Traveller

Video

PBX

LANS

Video

Phone

Fax

LAN

PC

Internet

PC

Phone

PC

PhoneFax

PC

LANS

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User/Access SitesHome Office

(Single User)Applications

• Internet Access• On-Line Services Access• Telecommuting• Shopping

Access Lines• Circuit Switched

Traffic• Data• Voice• Fax

Phone

Fax

PC

Phone

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Applications• Internet Access• Telecommuting• Electronic Commerce• Storefront

Access Lines• Circuit Switched

Traffic• Data• Voice• Fax

User/Access SitesSmall Office(Multiple Users)

PC

Phone

PC

PC

LAN

LAN

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User/Access SitesRemote Office

(Multiple Users)Applications

• Internet Access • Intranet/Extranet Access• Corporate Access• Telecommuting• VideoConferencing

Access Lines• Circuit Switched• Leased

Traffic• Data• Voice• Fax• Video

Video

Phone

Fax

LAN

PC

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User/Access SitesCorporate Enterprise

Video

PBX

Applications• Internet Access • Corporate Communication• Intranet/Extranet Access• Telecommuting• VideoConferencing• Electronic Commerce• Virtual Private Network


Traffic• Data• Voice

•Fax•Video

Video

PBX

LAN

LAN

PC

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User/Access SitesCorporate Backbone Network

Application• Internet Access• Intranet/Extranet Access• Network Management• Virtual Private Network

Access Lines• Leased


Internet

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User/Access SitesISP POPApplications

• Internet Access• Network Management • Web Site • Security• Virtual Private Network• Wholesaling



InternetInternet

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What Is Internet Access?

• The use of service provider offerings to establish aconnection between a user’s location and the Internet

• This may be either analog or digital• The traffic may be data, voice or fax• Access may be through an Internet service provider’s

point of presence or a corporate gateway

Internet Service

Provider

Telecommuter

LANRemote Office

Customer SiteLAN

CarrierServicesInternet

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Logical Networks

InternetAccessSite B

AccessSite A

UserSite A

UserSite B

Telephony NetworkInternetA Virtual Private Network

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Where Are We Going?Public Switched Public Internet Telephone Network Protocol NetworkDesigned a Century Ago Designed for Modern High-speedfor Analog Voice Digital CommunicationsCircuit-oriented Packet/celłframe-orientedPoint-to-Point Only Point-to-Point

Any-to-AnyAny-to-Many

“Constant Bit Rate” Only Constant, Variable and AvailableBit Rates

64 Kbps Channels Only Virtually Unlimited BandwidthComplex Layer-1 Signaling Simple Layer-2,3 Switching/RoutingDifficult and Expensive to Scale Scales Easily and AffordablyLimited “Add-on” Management Management Features Built-in

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How Much Network Bandwidth Is There?

Copper(Electrical)

DS0 64 KbpsDS1 1.54 Mbps (24 DS0s)DS3 43 Mbps (28DS1s)

Fiber(Optical)

OC-1 50 MbpsOC-3 155 Mbps (3 OC-1s)OC-12 622 Mbps (4 OC-3s)OC-48 2.5 Gbps (4 OC-12s)

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Physical Network

= Switch

= Network Trunk

= Access Line

= User Site

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Virtual Private Network

VPN 1 VPN 4VPN 3VPN 2

PHYSICAL

LOGICAL

The Physical Network

Topology

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Network Trunks (T1)• Key point: The network is a fabric of 64 Kbps threads

(DS0s), originally designed to carry digital voice

On a DS1 trunk, 24 64 Kbps channels are timedivision multiplexed into one 1536 Kbps circuit

OneDS1

Circuit

24 channels

1 2 3 4 5 6 7 823 22 23 24 1 2 32124One DS1 frame (1536 Kbps)

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Leased Line Traffic(Point to Point Circuit)

One or more channels from origin todestination dedicated full-time to the user

User

Access Line(Local Loop)

AccessEquipment

CentralSite


AccessEquipment

CentralOffice

CentralOffice

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Circuit Switched Traffic(Time Division Multiplexed Bandwidth)

a.k.a. Public Switched Telephone Network (PSTN)

One or more channels from origin todestination dedicated to the user

for the length of the call

PSTN

User


AccessEquipment

CentralSite


AccessEquipment

CentralOffice

CentralOffice

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Central Office

CircuitSwitch

Access Lines Network Trunks

ServiceProvider

Networks

MDF = Main Distribution Frame

2 Wire

4 Wire

6 Wire

Point-to-PointCircuit

Circuit-SwitchedTrunk

MDFUsers

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Circuit Switched Access

• One 3.4 kHz channel• Up to 33.6 Kbps data using symmetric modem• Up to 56 Kbps data using asymmetric modem• In-band signaling (DTMF)

Analog2 wire

Access Equipment

PSTNCentralOffice

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• Two 64 Kbps data channels• One 16 Kbps out-of-band signaling channel• ISDN “U” (2 wire) or “S/T” (4 wire) interface

ISDN BRIU or S/T interface

Access Equipment

B2

D

B1 OneOne

CircuitCircuitBRIBRI

PSTNCentralOffice

D DD BRI frameB1B2 B2 B1 B2B1

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• 24 56 Kbps datachannels, 56 Kbps

• In-band signaling

T1 Access Line

4 wireAccess

Equipment

One T1 frame (1536 Kbps)

1 2 3 4 5 6 7 823 22 23 24 1 2 32124

OneT1

Circuit24 channels

PSTNCentralOffice

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Central SiteRemote User

Bandwidth Allocation Control Protocol(BACP)

• Adds control channel and intelligent dialing• Both ends communicate during session• Allows the dynamic allocation of bandwidth• Open specification allows interoperability

among multiple vendors’ equipment

End-to-end communicationschannel to control all circuits

used by MP

Multiple analog lines, switched56 circuits, ISDN B-channels, etc...

MP Datastream

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Circuit Switched Access with External WAN Interfaces

Access Server

LAN

AnalogModem

Users

DigitalISDN BRI

UsersDial-UpServices

MultipleDigital Access

Lines

MultipleAnalog Access

Lines

TAor

DSU

Modem

DigitalCalls

MultipleSerial Ports

AnalogCalls

ProtocolProcessing

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Circuit Switched Access with Integrated WAN Interfaces

AnalogModem

Users

DigitalISDN BRI

UsersDial-UpServices

100% Digital Access(ISDN PRI, T1 or E1)

IntegratedTAs and

DSUs

IntegratedDigital

Modems

Protocol Processing

Access Server

AnalogCalls

DigitalCalls

LAN

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Today’s Circuit Switched/Leased Point-to-Point Connections to the

Internet Protocol (IP) Based Internet

TheInternet

Leased orCircuit

Switched

CircuitSwitched

Circuit Switched

CircuitSwitched

ISP

ISP

ISP

ISPCorporateLocation

RemoteOffice

Leased

MobileTravelers

Customer/Supplier

Telecommuter

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IP Based Internet UsesPacket Switched Traffic

(Statistically Multiplexed Bandwidth)

A packet protocol over fixed bandwidth circuitsthat can be shared by multiple users

data data data

data data

data

data data dataDigitalDigitalCircuitCircuit

examined by switch

FLAG

address dataframecheck

sequence

FLAG

examined by switch

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Packet Network Virtual CircuitsFrame Relay or ATM

Virtual Circuit• Provides connectivity between locations

Switched Virtual Circuit• Dynamically established when needed• Released when not needed

Permanent Virtual Circuit• Statically defined at configuration• Always configured (active or idle)

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Packet Switched AccessDigital Subscriber Line (xDSL)

• DSL Technologies– IDSL– HDSL– SDSL– ADSL-CAP, ADSL-DMT

• High bandwidth over existing “localloop” twisted pair of wire

Access Equipment

Access Line(Local Loop) Central

OfficeUser PacketNetwork

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xDSL Access Options

Central Office

SOHOCopper Loops

Any ISDN CPE

SOHO

SOHO

Ethernet

Ethernet

Ethernet

IDSLUp to 128 Kbps

SDSLUp to 768 Kbps

ADSŁData w/POTSUp to 7 Mbps

POTSSplitterPSTN

PacketNetwork

COCircuitSwitch

DSLAccess

Module

MDF

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Packet Switched AccessISDN Digital Subscriber Line (IDSL)

• IDSL – Technological innovation from Ascend• 128 Kbps symmetric data rate• Single pair local loop to 18,000 ft.• Compatible with any ISDN BRI TA, bridge or router• 2B1Q line code for transparent operation

data

dataAccess Equipment

Packet NetworkIDSL

2 Wire data

dataCentralOffice

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Packet Switched Access ISDN Digital Subscriber Line (IDSL)

Voice and Data

Telephone CompanyCentral Office

2-Wire Local Loop

CO CircuitSwitch

Customer Premises

T1 orT1/PRI

PacketNetwork(IP, ATM,

Frame Relay)

PSTN

Ascend Communications

Extending the Internetto Meet Your Needs

Ascend

Technology