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Quality of Service in Internetworks

Quality of Service in Internetworks. Exercise 1 Rate control. Example setting. A topology consisting of: Customer site with traffic sources/sinks Access Provider Edge device linked to CE with sufficient delay Arbitrary headend of traffic. Token bucket rate control.

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Quality of Service in Internetworks

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  1. Quality of Service in Internetworks Exercise 1 Rate control

  2. Example setting • A topology consisting of: • Customer site with traffic sources/sinks • Access Provider Edge device linked to CE with sufficient delay • Arbitrary headend of traffic

  3. Token bucket rate control • Decide on three or more distinctively different unicast flow types • UDP vs TCP • Long vs short-lived • Bandwidth consumption (and possible variation thereof) • Burstness of outbound traffic • Simulate said flow types on given topology • Create different token bucket policies and install them one at a time on PE ingress port • Limit the total accepted throughput to 1, 2, and 10 Mbit/s • Also remember to add some delay to the link • Send more traffic on the link that is accepted at PE

  4. Time sliding window rate control • Create a group of time sliding window policies • Perform the simulations in previous manner by setting the policies into PE ingress port and flooding the link • You can use same flow types as in token bucket but you can also create new ones in addition • How does the window size affect traffic behavior? • Does one type of traffic benefit more from sliding window than another?

  5. For both mechanisms • How do aggregate throughput, delay and other traffic properties behave with different policies? • How does packet loss occur over time • for TCP applications? • for UDP applications? • How much goodput is attained by an individual flow when tens or hundreds of flows are aggregated into the link? • Also for TCP/UDP • How do the methods differ from each other? • Can you say explicitly that one is better than the other? • Can you claim that either is better for a specific flow type?

  6. Weapon of choice • You can use whatever tool you see fit to perform the simulation • Omnet • ns2, ns3 • Matlab • Perl + awk + lots of glue • That extra Cisco 1200 you have in your dorm room • Virtual machines... • However, remember that this can distort the results in the worst case scenario • We’re interested in your reasonings based on the simulations • But feel free to add the simulation code as an appendix if you want to

  7. Deliverables • Do the aforementioned tasks, and return a written report of 2-3 pages • Emphasis on own observations, not producing textbook answers about mechanisms • Include any other thoughts about rate control that occurred to you during the exercise • This is not an English grammar course! • Good textual output is only appreciated, not seen as a heavy grading factor • Return date: 20.4.2009

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