Post on 12-Jan-2016
description
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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
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VPNs & Specialized Network Services continued
• ATM compared to IP
• SONET– In the backbone– In the metropolitan area– Compared to gigabit ethernet
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virtual private networks
Virtual: from the Latin excellence;Essence though not in fact actual
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IPSec virtual private network for remote access
•What are the advantages of VPNs?•Why are they important?•How can they be made secure?
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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
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Any-to-any mesh design in a VPN; hub and spoke (star) to headquarters forInternet access.
Mesh; hub & spoke combo
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Local and interexchange channels of a private line
•Billing, repair & installation ramifications
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Integrated access device for T-1s carrying voice and data
•Small & medium companies•Implication of competition
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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
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28 T-1s = a T-3 Circuit
ISP
Internet
London
Dallas
T-3T-1
T-1
Boston
Fiber or Wireless
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Videoconferencing using three bonded BRI ISDN circuits
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BRI ISDN bonding
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• 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
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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
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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
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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