1. Traffic and Cost Generator
Real network design is 90% of file preparation and data collection.
Some data need to be generated:
Future growth prediction
Large traffic demands (requirements, end-to-end traffic) data.
Only limited info available. Traffic generator can fill in the gap.
11/19/2018
C. Edward Chow

2. Delite Network File Format
Goal: simple extensible.
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C. Edward Chow

3. Tariff, Equipment, Param Format
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C. Edward Chow

4. Cluster Site Notation
Here the PARENT column deal with the homing of this site.
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C. Edward Chow

5. Sites Population and Level
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C. Edward Chow

6. Traffic Units for Various Networks
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C. Edward Chow

7. Traffic Generation
Assume Uniform Traffic. Traf(i,j)=C. Traffic from node i to node j is C.
Assume Random Traffic . Traf(i,j) is some distribution between a minimum and a maximum value. What distribution is the following code generated?
11/19/2018
C. Edward Chow

8. Random Mux Circuit Traffic Generation
D56 56kbps links
Nreq circuits will be generated.
11/19/2018
C. Edward Chow

9. More Realistic Traffic Formula 1
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C. Edward Chow

10. Add Offset and Scale Factor
A is scale factor
Population offset (say 0.05) avoid zeros;
Distance Offset.
11/19/2018
C. Edward Chow

11. Traffic Normalization
Example 4.1: 50 sites linked by 85 E1 lines. The average of hops is 2.75 and the links have an average utilization of What value of a should be chosen to generate the traffic?
Solution:
Total carried traffic on the network =
Let T=
We choose a =69,632,000/T
11/19/2018
C. Edward Chow

12. Row Normalization
With row indicating source, column indicating destination in the traffic matrix.
The traffic from node i to other nodes is
We can then define
This allows us to match the synthetic traffic to the observed traffic.
11/19/2018
C. Edward Chow

13. Row and Column Normalization
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C. Edward Chow

14. Example: 5 node network
Site data and observed Traffic in and out of a node.
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C. Edward Chow

15. 1st round with Pop_Power=1 and Dist_Power=1
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C. Edward Chow

16. 1st round Row and Column Scale Factors and Modified Traffic
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C. Edward Chow

17. 2nd Round Traffic Matrix
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C. Edward Chow

18. 2nd Round Row and Column Scale Factors
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C. Edward Chow

19. 5 Iteration later
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C. Edward Chow

20. Considering Level (Traffic Type of Nodes)
Level Matrix (uneven traffic btw Level 1 and Level 2)
Formula
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C. Edward Chow

21. Final Traffic Formula
Consider the random traffic, 0<=rf: random fraction<=1
11/19/2018
C. Edward Chow

22. Traffic Generators and Sensitivity Analysis
Often useful to generate traffic suites than a single set of traffic.
It can be used to study how network responds to change.
Sometimes, there is a requirement that network not be re-designed for a period of time.
11/19/2018
C. Edward Chow

23. A Case Study: “Green Field” Redesign of a Network
Green field mean “unconstrained to reuse the network already in place.
7 nodes in Squareworld.
Distance Matrix:
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C. Edward Chow

24. Parameter for Terminal Traffic
N1-N5 each has 100 users, N6-N7 each has 200 users. Level one has 600 users.
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C. Edward Chow

25. Modeling User Session Traffic Matrix (by observing control point data)
Here N4 and N7 have host computers.
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C. Edward Chow

26. Voice vs. Cost
Fixed cost of vs. time dependent cost of voice
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C. Edward Chow

27. Internal Email Traffic Parameter
Total population=900.
8 2000bytes in busy hour.
Why only normalize on ROW?
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C. Edward Chow

28. Internal Email Traffic Matrix
Generated by Traffic generator using the parameters in previous page. Note that the total traffic includes those that send to destination in the same site.
11/19/2018
C. Edward Chow

29. Internal Email Actual Traffic
Remove the diagonal entries leave the inter-site traffic.
11/19/2018
C. Edward Chow

30. Internal Web Page Traffic
25% web fetches are internal.
23 pages/hour/user
Each page access results 5 128Byte datagrams outbound and Byte datagrams inbound, 3500 byte HTML and related files inbound.
Outbound traffic/user=0.25*23*5*128*8/3600=8.177bps
Inbound traffic/user= *23*3500*8/3600=52.9bps.
TRAFIN and TRAFOUT only consider traffic initiated from the site.
11/19/2018
C. Edward Chow

31. Internal Web Page Traffic Parameter
The sum of row traffic = TRAFOUT
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C. Edward Chow

32. Internal Web Page Traffic Out
92*4+180*2=730? Vs 818 This is due to 818*(1/9)=92 of the traffic is intra-site. The other 818*(8/9)=727 is the actual TRAFOUT that spread to all other 6 nodes.
183*5+362=1277? Vs 1636 due to Arbitrary Dist_offset?
11/19/2018
C. Edward Chow

33. Internal Web Page Traffic Inbound
The ratio between the inbound traffic and outbound traffic = 52.90/8.177=
The inbound traffic matrix= * Ttr where Ttr is the transpose of matrix T.
11/19/2018
C. Edward Chow

34. External Web Page Traffic
75% of web traffic to external sites.
23 pages/hour/user
Each page access results 5 128Byte datagrams outbound and Byte datagrams inbound, 3500 byte HTML and related files inbound.
Outbound traffic/user=0.75*23*5*128*8/3600=24.533bps
Inbound traffic/user= *23*3500*8/3600=158.70bps.
Typo in text: “8.17 plus” should be “ plus”
11/19/2018
C. Edward Chow

35. Partition DB Site Traffic
Total DB=200GB, 80 GB at N1, 60 GB at N4, 60GB at N7.
900 users. Per user has 15 queries/hour, 300B request(out), 4000B data(in). 3 updates/hour, 8000B(out), 1000B(in).
Query traffic to server: 15*300*8/3600=10bps.
Query traffic from server: 15*4000*8/3600= bps.
Update traffic to server: 3*8000*8/3600=53.333bps.
Update traffic from server: 3*1000*8/3600=6.666 bps.
100*( )= *( )=14000
63.33*900*0.4=22,799
140*900*0.4=50,400
N1 has 80GB, 40% of Total DB.
11/19/2018
C. Edward Chow

36. Partition DB Traffic Inbound
40% of N outbound DB traffic go to N1=0.4*6333=2533.
0.3*6333=1900 to N4 and 1900 to N7.
11/19/2018
C. Edward Chow

37. Partition DB Traffic Outbound
The ratio between the inbound traffic and outbound traffic = 14000/6333.
The inbound traffic matrix=14000/6333* Ttr where Ttr is the transpose of matrix T.
11/19/2018
C. Edward Chow

38. Replicated DB Client-Server Query
DB are replicated at site N1, N4, and N7.
Assume static allocation of clients to servers. N5N1, N3N4, N2,N6N7.
N5 has 100 pop*10bps/pop=1000 bps query outbound; 100*133.33=13,333 bps query inbound.
11/19/2018
C. Edward Chow

39. Replicated DB Client-Server Update
DB are replicated at site N1, N4, and N7.
Assume static allocation of clients to servers. N5N1, N3N4, N2,N6N7.
N5 has 100 pop*53 1/3 bps/pop=5333 bps update outbound; 100*6 2/3=666 bps update inbound.
11/19/2018
C. Edward Chow

40. Replicated DB Update Server-Server
Same 53 1/3 bps update request per user and 6 2/3 bps update response per user.
N4 has update requests from N3 and N4 (200 users)= 200*53 1/3=10,666. Those will relay to N1 and N7. N4 also responds to N1’s update (including N1 and N5, 200 users)=200*6 2/3=1333. Therefore it is ,666 to N1.
N1 has update requests from N1 and N5, 200 usres=200*53 1/3=10,666. N1 also responds to N7’s update (including N2,N6, N7, 500 users)=500* 6 2/3= Therefore it is 10, to N7.
11/19/2018
C. Edward Chow

41. Usage-Sensitive Voice Tariff
In most data networks, the cost of bandwidth is the largest expense item.
A router $10,000 is amortized to $300/month.
It can terminate links that cost $20,000/month.
11/19/2018
C. Edward Chow

42. Usage-InSensitive Voice Tariff
Banded Wide Area Telephone Service (WATS).
Banded WATS (4 hours/day) means a service that allow up to 4 hours of call per day to locations within a certain distance, say 250 miles.
11/19/2018
C. Edward Chow

43. ISDN
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C. Edward Chow

44. Usage-InSensitive DataTariff (UK
US tariff is much cheaper.
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C. Edward Chow

45. Tariff Taxonomy Four type of links:
Fixed virtual circuit (leased link for voice and data) installation cost= 10~20 monthly rent
Dialed virtual circuit. (setup on demand; limited speed choices)
Fixed pipes: accept bit at certain rate and make the best effort to deliver it, e.g., X.25, frame relay, Switched Multi-megabit Data Service (SMDS). Two rates: peak rate (circuit rate), say 64kbps, and committed information rate (CIR), say 16kbps, guaranteed.
Dialed pipes. Setup on demand; usage-sensitive charge.
List of possible fees:
Access fees (for maintaining the connections)
Setup fees
Teardown fees
Usage fees. Depending on Channel capacity, CIR, Distance, Time of Day, National and administrative borders
11/19/2018
C. Edward Chow

46. Cost Model
Distance-based Costing There are anomalies just like airfare due to competition
Linear Distance-Based Costing=a+b*d where a=fixed cost; b=variable cost; d=distance a and b can be derived from samples in the tariff table using least-square curve fitting.
For example, at UK cost=$ $2.40/km*d at US cost=$ $0.49/mile*d
Piecewise-Linear Distance-Based Costing
Piecewise-Constant Distance-Based Costing
11/19/2018
C. Edward Chow

47. Piecewise-Linear Distance-Based Costing
Many tariffs are published in piecewise-linear format.
T1 cost in US/Mexico
56Kbps cost in US/Canada
11/19/2018
C. Edward Chow

48. Piecewise-Constant Distance-Based Costing
Banded charges in Japan for D64 link.
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C. Edward Chow

49. Tariff Related Issues
No direct circuit (unusal connect)Tariff not filed.
Low cost tariff  when you go to provision the circuit, there may not have facilities or take long time to get on.
In US, there is a notion of Local Access and Transport Area (LATA). Within LATA is much cheaper than in end-points at different LATA.
There may be multiple carriers and require optimization.
11/19/2018
C. Edward Chow

50. Cost Generators Implemented in cost-gen.c
Cost generator 1: use C(i,j,k)=Fk+d*DCk site I to site j with type k link. DC variable cost. F: Fixed cost.
Cost generator 2: use
Cost generator 3: take into consideration different nations.
Cost generator 4: involve two countries, two half-circuit costs
Cost generator 5: override case
11/19/2018
C. Edward Chow