ICSA%20745%20Transmission%20Systems%20Introduction

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ICSA 745 Transmission SystemsIntroduction

• Nirmala Shenoy
• Dept. of Information Technology
• Rochester Institute of Technology

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Scope

• Current communication technologies (emerged)
• Problems associated with these technologies
• Need for new technologies (emerging)
• Requirements of new technologies
• Requirements of Applications
• growing
• General overview of emerging technologies

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Need for enhanced services

• Limitations of Legacy Technologies- X.25 T1/E1
• Popularity of LANs
• Interconnecting LANs high speed
• Protocols for interfacing
• Complex environment
• Continued incompatibility
• Growing Application Requirements

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Need for enhanced services

• Growing Application Requirements
• Urgent need for high capacity communications
• Efficient handling of these applications
• Quality constraints guarantees

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Goals of Emerging Technologies

• Integrating Networks
• Common interfaces, protocols
• Provide high-throughput
• very fast transmission speeds
• incurring little delay delay sensitive
  applications
• Support high-capacity networks - backbones

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Goals of Emerging Technologies

• Support any type of application
• Voice, video, data, combination
• Provide better network mgmt. Tools
• An essential accessory
• Seamless connection between networks
• LAN interconnectivity

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Upcoming Requirements

• Greater Communications capability
• Optic fibre?
• Requirements of powerful applications
• Bandwidth thirsty applications
• Virtual reality?
• LAN / WAN interworking
• issues

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WAN - LAN Differences

• Error rates
• WAN relatively high - LAN relatively low
• Channel Capacity
• WAN relatively low - Kbits/sec
• LAN relatively high Mbits/sec
• Geographic spread
• Ownership of network

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LAN / WAN InterconnectivityIn the Past

• Connected with bridges, routers, gateways, and
  packet-switched networks
• Used dedicated communications channels
• Problems
• expensive no backup capability
• extensive processing of traffic has created
  unacceptable time delays for certain apps.

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Solution- Virtual Private Networks?

• Users share communications channels
• Switches allow an end user to have access to
  multiple end sites
• Ideally no perception of sharing virtually
  private

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Virtual Private Networks

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Solutions-Emerging Technologies

• Frame Relay
• Fast relay service with minimal network support
• Fast and Switched Ethernet
• Switched Multi-Megabit Data Service
• A public high-speed transport service
• Wireless (Mobile) Systems

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Emerging Tech. (cont.)

• Asynchronous Transfer Mode (ATM)
• A high-speed virtual circuit, cell relay
  technology
• Synchronous Optical Network (SONET)
• A high-speed synchronous carrier system using
  optical fiber and a digital multiplexing
  hierarchy
• Broadband Signaling
• Intelligent networks

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Emerging Technology basis

• Fast Relay Systems relay traffic quickly

Frame Relay
Cell Relay
(Variable size frames)
(fixed size cells)
ATM
802.6 SMDS
LAPD
LAPD Q.931
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Evolving Technology

• Hardware and software
• software moved into hardware
• Transmission channels
• optical fiber
• Computer
• increased power
• increased memory and disk

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Some Conclusions

• Powerful applications and their need
• Bandwidth availability
• Decreased costs for BW usage
• Increased computing power
• Decreased computing costs

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Necessity for more powerful networks

• Broadband networks
• Early Networks that uses high-frequency analog
  technology as transport mechanism
• Current Megabit or higher capacity systems that
  offer a multimedia transport system
• Broadband signaling

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Performance Distance considerations
bandwidth

ATM
Fast Ethernet
FDDI
Frame relay
MAN SMDS
Ethernet Token ring
ISDN BRI
distance
WAN
LAN
MAN
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Key concept- Bandwidth on Demand

• User can request and receive network capacity
  dynamically
• Committed or Sustained Information Rate
• CIR or SIR
• Help regulate traffic
• User choice of throughput rate
• Determine pricing structure for service

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Bandwidth on Demand (cont.)

• Burst traffic
• Maximum rate excess rate
• Issues
• Service charge up to CIR
• Service charge beyond CIR
• Discard traffic information to user
• Price apportioned for discard traffic

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Network Domains for service

network
network
Between network
within network
user
user
Between user network
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Network interfaces

• User network Interface - UNI
• Network Network interface -NNI