1

VPNs & Specialized Network Services

• Virtual private networks– Lowering the cost of enterprise links & enabling

remote access

• Frame relay as a replacement for private lines• T-1/E-1 the first high speed service; • ISDN - caller ID & video conferencing• Gigabit Ethernet in carrier & enterprise

metropolitan networks

2

VPNs & Specialized Network Services continued

• ATM compared to IP

• SONET– In the backbone– In the metropolitan area– Compared to gigabit ethernet

3

virtual private networks

Virtual: from the Latin excellence;Essence though not in fact actual

4

IPSec virtual private network for remote access

•What are the advantages of VPNs?•Why are they important?•How can they be made secure?

5

Key Components of Frame relay

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Multipoint private lines with hub and spoke for small locations

•Why use private lines rather than a virtual private network?

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Mesh network topology pros & cons

8

Any-to-any mesh design in a VPN; hub and spoke (star) to headquarters forInternet access.

Mesh; hub & spoke combo

9

Local and interexchange channels of a private line

•Billing, repair & installation ramifications

10

Integrated access device for T-1s carrying voice and data

•Small & medium companies•Implication of competition

11

T-1 and E-1

• 1.544 or 2.048 Megabits per second– Bell Standard– IT Standard

• Applications

T-1 Mux T-1 Mux

24 or 30 channels 24 or 30 channels

Fiber, copper or wireless media

12

28 T-1s = a T-3 Circuit

ISP

Internet

London

Dallas

T-3T-1

T-1

Boston

Fiber or Wireless

13

Videoconferencing using three bonded BRI ISDN circuits

14

BRI ISDN bonding

15

• PRI ISDN carrying the caller’s billed telephone number automatic number identification (ANI). The ANI is often the same as the customer’s telephone number.

Primary rate interface ISDN

16

DSLAMs in digital loop carriers (remote terminals)

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Digital subscriber line service

• No need for fiber to the home or business

• A response to cable providers

• Use of same copper already deployed

• Strategic implications of RBOC & cable offerings

downstream

voice

data

upstream

18

DSLAM connection to an Internet service provider

19Figure 5.14Neighborhood mini remote access multiplexers (MiniRAMs).

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Gigabit Ethernet

fiber-optic cabling and metropolitan fiber rings

21

Leasing wavelengths in the metropolitan area

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Parallel streams in an ATM circuit

•Fixed size cells•Quality of service•Asynchronous switching•In the frame relay backbone

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- bidirectional duplicate rings in a carrier’s backbone network- The fiber glut & pricing- SONET in the enterprise

SONET rings in the backbone

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Summary

• What are the major trends in high-speed networking

• Why are carriers, residential consumers and enterprises demanding higher-speed services

• Which technologies will supply the required capacity and speeds?

• Contrast & compare: ISDN, T-1, T-3, Gig-E, SONET & ATM