Implementing a Reliable Transport Protocol

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Implementing a Reliable Transport Protocol
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Content

• Project introduction
• Network Simulator introduction
• Environment interface

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Project introduction

• Implementing a simple reliable data transfer
  protocol
• Since you probably don't have standalone machines
  (with an OS that you can modify), your code will
  have to execute in a simulated hardware/software
  environment
• It runs on a simulated environment

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Project introduction

• The procedures are for the sending entity (A) and
  the receiving entity (B).
• Only unidirectional transfer of data (from A to
  B) is required.
• B side will have to send packets to A to
  acknowledge (positively or negatively) receipt of
  data.

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Project introduction
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Content

• Project introduction
• Network Simulator introduction
• Network event
• Environment interface

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Network Simulator introduction

• Compared to the cost and time involved in setting
  up an entire test bed containing multiple
  networked computers, routers and data links,
  network simulators are relatively fast and
  inexpensive
• NS2, QualNet, OMNet

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NS2 Event Scheduler
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Network Event in this Project
struct event float evtime /
event time / int evtype / event
type code / int eventity / entity
where event occurs / struct pkt pktptr
/ ptr to packet (if any) assoc w/ this event /
struct event prev struct event next
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Event Scheduler
time, type, entity, pkt, next, previous
head_ -gt
head_ -gt
Call function based on event type
insert
time, type, entity, pkt, next, previous
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Content

• Project introduction
• Network Simulator introduction
• Environment interface

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Environment interface

• starttimer
• Insert an event into the list
• stoptimer
• Delete an event from the list
• tolayer3
• Send packets into layer3
• Insert an event into the list

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Project2 What to turn in

• 1. A report describing your implementation, and
  how to compile/run your program.
• 2. Your source code
• 3. Output from your test runs. 
• Carefully choose probabilities of loss and
  corruption so you dont have too much output.
• Annotate your printout with a colored pen showing
  how your protocol correctly recovered from packet
  loss and corruption.
• Let your procedures print out a message whenever
  an event occurs at your sender or receiver (a
  message/packet arrival, or a timer interrupt) as
  well as any action taken in response. The output
  should include for a run up to the point
  (approximately) when 5 messages have been ACK'ed
  correctly at the receiver, and a trace level of
  2.