University of Kansas
Electrical Engineering & Computer Science
EECS 863 Homework 5
Class of Service Queueing for the Internet
The purpose of this homework is to study the use of priority queueing
to provide Class-of-Service in the Internet. It is expected that you will report the quality of your performance estimates. To simplify your top level system model it is expected that you will use the hierarchical modeling capability in Extend and include documentation of your blocks in Extend. Submit a print out of your top level model. Submit (send me) your .mox file.
A router output port operates at C Mb/s and supports
three traffic types:
- Best-effort data traffic
- Assume uniformly distributed message lengths
with a range of 100 to 1900 bytes, and exponential interarrival times
with an average of 0.6 ms
- VBR (Variable Bit Rate) video traffic
- Assume exponential message lengths with an average
of 20 Kbytes and fixed interarrival times of 5 ms
- Constant Bit Rate (CBR) fixed rate traffic. Assume
fixed length messages, 80 bytes and fixed interarrival times of 0.4 ms
- 20 pts Assume all three traffic classes are statistically multiplexed in one buffered onto one link. Is the link overloaded for link speeds of C= 5 Mb/s, 35 Mb/s, 50Mb/s, and 600 Mb/s.
- 20 pts Assume all three traffic classes are statistically
multiplexed onto one link. For link speeds of C= 5 Mb/s, 35
Mb/s, 50Mb/s, and 600 Mb/s use simulation to estimate the average end-to-end delay. Comment on the validity of the results for the overloaded cases. The delay measurements should be taken from the source to the
destination and they should be reported for all packets and by priority class.
- 20 pts Repeat the simulation in part 1) assuming non-preemptive
priority service, with the priority order (CBR) highest priority, (VBR) next
level of priority and Best-effort having the lowest priority.
- 20 pts Discuss the
impact of priority service on the average delay as the capacity increases.
Victor S. Frost, email@example.com