Calculations of Line Cost

1
Group 11

• Jennifer Miller
• Crystal Crow
• Jennifer Robertson
• Cindy King

2
Syncrasy Corporation

• Mail order operations and discount computer
  stores
• Computers in
• Chicago
• New York
• Atlanta
• Houston
• Los Angeles
• San Francisco
• Kansas City

3
Chicago, New York, Los Angeles

• Five terminals each (Other stores will have
  three)
• The catalog stores will be located 15, 20, and 40
  mi from the discount stores, respectively

4
Computer Store Transaction Types

• Inventory and receipt transactions
• Parts and customer inquires
• Catalog Store Activity

5
Inventory and Receipts

• Part number, quantity sold, unit price, discount
  rate, and total amount of the sale are
  transmitted to the central computer
• 22 characters, and the total amount of the sale
  is a 10 character field
• Orders more than 1000 are an exception and
  require a credit check

6
Inventory and Receipts cont.

• Average processing time is .5 sec.
• Average time for an order over 1000 is .8 sec.
• Peak transaction periods are from noon to 100
  p.m. and 500 p.m. to 600 p.m.
• It is required that 95 of all transactions of
  this type have a 3 sec. response time

7
Parts and Customer Inquiries

• Average input is 10 characters and average
  response is 500 characters
• Average and peak rates fro this transaction are
  both 10 per hour per terminal
• A response time of 4 seconds is required.
  Processing time is 1.5 sec. per order

8
Catalog Store Activity

• Activity will decline
• Catalog stores have eight terminals each
• 500 characters of input data and a 100 character
  response
• 20 orders per hour, with a peak of 30 orders per
  hour. 5 sec. responses time and processing time
  of 2.5 sec. per order

9
Prices, Equipment, and Mileage

• Only leased transmission lines
• Satellites were considered but it was dismissed
  because of the light amount of traffic from the
  stores and the effect of propagation delay on the
  response times.

10
Modems

• Cost has declined
• Modems wont be leased
• Calculations are for monthly fees only, excluding
  modem costs
• Buy statistical multiplexers with integrated
  modems

11
Interstate Communication Lines
The line can handle speeds up to 38,400 bps.
Line speed is governed by the modem.
12
Local Communication Lines

• The line can handle speeds up to 38,400bps. Line
  speed is governed by the modem

13
Statistical Multiplexer
Leased stat muxes with additional memory built-in
modems
14
Concentrators

• Price varies
• This case uses two configurations
• Sell for 30,000 or leased for 1,500 monthly.
• Up to 32 output lines
• Point to point
• Multipoint communications lines
• Lines to another concentrator

• Second configuration large enough to handle all
  transactions
• Sells for 40,000 or leased for 2,000 monthly
• Able to accommodate up to eight incoming lines
  from the host processor

15
Front End Processors

• The price of the FEP, 40,000, is the same as
  that of the more expensive concentrator

16
Terminals

• Dumb terminals sell for 500, with a monthly
  lease price of 50.
• Smart terminals sell for 1,200, with a monthly
  lease price of 95.
• Intelligent terminals sells for 1,500, with a
  monthly lease price of 105.

17
Mileage Chart
18
Mileage Costs

• Carriers are solicited for bids
• Network Modeling Systems are used for more
  locations to analyze best alternatives
• This case study used hand calculations instead of
  the modeling system

19
Long-Distance Line Costs
(100) (2.52) (900) (0.94) (547) (0.58)
1415.26
20
Minimum-Distance Costs
21
Local Line Costs
22
Shortest Route Network Configuration
Chicago
N.Y.C.
809
San Francisco
542
Kansas City
708
Atlanta
387
1547
743
Los Angeles
Houston
23
Calculations of Line Cost

• Five items must be considered in calculating the
  cost of a line they include
• Overhead
• Response Time
• Aggregate Data Rate
• Line Contention
• Configuration

24
Overhead

• Overhead reflects how efficiently the lines are
  used.
• Overhead cost include
• Control Messages
• Polling
• Terminal Access
• Wait Time Polling Intervals x (number of
  terminals 1)/2

25
Response Time

• Factors in
• Inventory Receipts
• Parts Customers Inquires
• Catalog Store Transactions
• 6 lines items X 22 characters per line 132
  Characters

26
Aggregate Data Transmission Rate

• 283150 char. per hour 78 char. per sec.
• 283150/3600 sec per hour about 78

27
Line Contention

• A 2400 bps one is adequate in a point to point
  environment, although not if two terminals
  attempt to start a transaction at the same time.
  If a random transaction rate is assumed use the
  following formula
• Pk(T) (LT)k (k!)(e-LT)

28
Configuring the System

• Example of the east coast

Chicago
NYC Catalog
NYC Discount
Kansas City
Atlanta
29
Configuring the System West Coast
C Concentrator 4 4-Port Mux 8 8-Port Mux 16
16-Port Mux
San Francisco
8
Chicago
New York
8
C
16
16
Kansas City
4
4
16
8
16
4
4
4
4
8
4
8
4
LA
Atlanta
8
Houston
30
Final Costs
31
Monthly Equipment Cost for the Kansas City,
Chicago, New York City, and Atlanta Branches of
the Network
Multiplexers 2 16-port muxes at 358
each 716 4 8-port muxes at 225 each
900 2 4-port muxes at 150 each
300 Modems Purchased or integrated with
muxes Terminals 11 Intelligent terminals at 105
each (two terminals available from
mail- order store) 1155 Concentrator
1 1500 each 1500 Subtotal 4571
32
Monthly Equipment Cost for the Kansas City to
Kansas City Branch of the Network
Multiplexers 2 4-port muxes at 150
each 300 Modems Purchased or integrated with
muxes Terminals 1 Intelligent terminal at 105
each (two terminals available
from mail-order store) 105 Subtotal
405
33
Monthly Equipment Cost for the Kansas City to
Houston Branch of the Network
Multiplexers 2 4-port muxes at 150
each 300 Terminals 3 Intelligent terminals at
105 315 Subtotal 615
34
Monthly Equipment Cost for the Kansas City to Los
Angeles to San Francisco Branches of the Network
Mutiplexers 2 16-port muxes at 358
each 716 2 8-port muxes at 225 each
450 2 4-port muxes at 150 each
300 Modems Purchased or integrated with
muxes Terminals 6 Intelligent terminals at 105
each 630 (two available from the
mail- order store) Subtotal
2096
35
Total Monthly Costs for the Network
Total equipment 7,687 Total long-distance
line costs 5,203 Total local line costs
352 Total network costs 13,242
36

• Syncracy will have to sell a lot of equipment to
  support this 13,242 per month configuration.
  However, there is the existing alternative of
  attaching to a packet distribution network (PDN).
  Because the amount of data being transmitted is
  small and PDNs charge by the number of packets
  and not by the connect time, the overall cost
  could be lower.

37
Summary
38

• Two basic transactions at each computer store
• inventory and receipt transactions
• parts and customer inquiries
• The expansion of the corporation entails prices
  of equipment and mileage
• Equipment costs are for multiplexers,
  concentrators, terminals and mileage

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• The terminals are intelligent and leased by the
  month
• Mileage cost was determined for Kansas City to LA
  in Long-Distance Line Costs and Local Line costs
• The calculation of line use cost was determined
  by overhead, response time, aggregate data rate,
  line connection, and configuration.
• All costs were combined together to get a total
  monthly cost rate of 13,242 (158,904 for a
  year)

40
Jennifer Millers Question

• What was the reason that the use of satellite
  transmission was dismissed by Sycrasy?

41
Crystal Crows Question

• How was the difference between the lower cost and
  high cost configuration and why are they not the
  final configuration?

42
Jennifer Robertsons Question

• What must be considered when calculating line
  cost?

43
Cindy Kings Question

• What would make the overall monthly cost lower?

44
FIN