CATV Networks Bandwidth Allocation for the Upstream Channel

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CATV Networks Bandwidth Allocation for the
Upstream Channel
mid term presentation (winter 2001)
A project by Chen Yaniv 031763071 Lavi
Abramovich 032214363
Instructor Nir Menkerman
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Project Definition
Learning and Understanding the DOCSIS/MCNS cable
modems protocol.

Developing an efficient scheduling algorithm for
the Cable Modem Termination System (CMTS).

Demonstrate the algorithm behavior with a
software implemented simulator.

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Why Cable Network ?(Physical Layer)
Transparent IP Traffic, Through The
Data-Over-Cable System
- Economic

• Broadband communication
  service.

- Widespread
- Integrate all communication services (Video,
Data)
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Bandwidth Allocation MAC Layer
The upstream channel is modeled as a stream of
mini-slots.
The CMTS allocates the upstream slots by
broadcasting a map message to the CMs.
Mini slots
Previous map
current map
Yet unmapped time
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Requests

• The map includes allocation of the following
  types of upstream messages for the CMs (SIDs)
• Unicast (data or request) supports piggyback
• Multicast (requests)
• Data/Request immediate access
• contention resolution based on exponential back
  off .

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Map Properties
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CMST Transportation Policy
QoS demands for Min/Max bandwidth, Timing

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Best Effort
We will focus on developing the algorithm for
supplying the regular users, the best bit rate
possible.
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Best Effort Example
N 4 C 100
N 2 C 20
N 1 C 5
N 1 C 0
50
30
20
10
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Work Plan
Week 9-10 - finish the algorithm development and
understanding the simulator environment.
Week 11-12 develop the simulator.
Week 13-14 debugging and problem solving.
Week 14 conclusions and final report.