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This topic provides information about interpreting
traffic report findings. The various reports can be helpful tools
for system planning, diagnosing system and subscriber problems,
and for recognizing and diagnosing trends.
The following topics provide information on interpreting traffic
report findings:
Feature reports and grade of service
The Feature Daily or Feature Hourly Traffic Reports each display
two separate reports. These reports list session traffic or message
traffic information for up to 32 consecutive days or 192 consecutive
hours, respectively. The Average IMAPI Sessions in Use field is
particularly important fields in the Feature Daily and Hourly Traffic
Reports.
These reports play an important role in determining your system's
grade of service (GOS). Among other things, GOS is used in determining
port requirements. Port requirements on the messaging system are
based on the use of ports for all applications, including call answer,
messaging (voice, email, and fax), automated attendant, and call
delivery.
Definition of grade of service
GOS is a parameter that describes the delays in accessing a port
on the messaging system. Ideally, it is recommended that enough
ports be provided so that there is always a port available. However,
this is not necessary since calls are queued in an automatic call
distribution (ACD) group or hunt group until a port is available.
This is acceptable to subscribers as long as the delays are not
too long.
GOS is defined as the fraction of calls that are queued for longer
than 10% of the average holding time on the ports. For example,
if the average holding time on an messaging system port is 100 seconds,
a 0.05 GOS means that 5% of the calls will experience queuing delays
of greater than 10 seconds. A 0.05 or lower GOS is generally recommended
for the messaging system.
Determining grade of service
To determine the GOS on an installed messaging system, you must
retrieve the average number of ports used during the busiest hour
from the system traffic data. Retrieval can be done by locating
the Maximum Average Ports in Use field on the Feature Daily Traffic
screen. Calculate the average of this value over several days to
get a reliable indicator.
Next, locate the number of ports on your system in the first column
of the Messaging port capacity in erlangs (avg.
ports in use) at various GOS table. Look across the row until
you find the number equal to or just larger than your Maximum Average
Ports in Use value. The number at the top of the column
is the GOS during the busiest hour.
Example of how to determine grade of service
For example, say that you have a system with 12 ports. Over the
course of five business days, you record the value in the Maximum
Average Ports in Use field on the Feature Daily Traffic screen.
You add the five numbers together and divide by five to get an average
of 7.25. You then look in the Port column in the table for the row
that starts with 12 (the number of ports in this sample system).
Looking across that row, note that the value that is equal to or
just larger than 7.25 is 7.38. The GOS at the top of that column
is 0.05.
You can also use the table to determine the number of ports required
for a system under the present load. For example, if a 0.03 GOS
is desired, look for the column with the heading of 0.03 GOS. Look
down that column to find the number equal to or just larger than
the value in the Maximum Average Ports in Use field from the Feature
daily traffic screen. Then look across to the value in the left-hand
column of that row to determine the number of ports required for
a 0.03 GOS.
To continue this example, say that your Maximum Average Ports
in Use is 45. Looking down the 0.03 GOS column, the closest value
to 45 is 45.38. Looking leftward to the corresponding Port column,
you see that 56 ports are required to maintain a 0.03 GOS. Note
that ports are always sold in increments of two, so if the number
of ports shown is an odd number, round it up by one.
Table: Messaging port capacity in
erlangs (avg. ports in use) at various GOS
| Ports |
0.01 GOS |
0.02 GOS |
0.03 GOS |
0.04 GOS |
0.05 GOS |
0.06 GOS |
0.08 GOS |
0.10 GOS |
| 2 |
0.16 |
0.23 |
0.29 |
0.33 |
0.38 |
0.41 |
0.48 |
0.54 |
| 3 |
0.47 |
0.61 |
0.71 |
0.79 |
0.86 |
0.92 |
1.03 |
1.12 |
| 4 |
0.89 |
1.09 |
1.22 |
1.34 |
1.43 |
1.51 |
1.65 |
1.78 |
| 5 |
1.38 |
1.64 |
1.81 |
1.94 |
2.07 |
2.17 |
2.35 |
2.49 |
| 6 |
1.92 |
2.24 |
2.44 |
2.60 |
2.74 |
2.86 |
3.06 |
3.22 |
| 7 |
2.51 |
2.86 |
3.11 |
3.31 |
3.44 |
3.58 |
3.81 |
4.00 |
| 8 |
3.14 |
3.53 |
3.81 |
4.00 |
4.17 |
4.33 |
4.58 |
4.78 |
| 9 |
3.78 |
4.22 |
4.53 |
4.75 |
4.94 |
5.08 |
5.36 |
5.58 |
| 10 |
4.44 |
4.92 |
5.25 |
5.50 |
5.69 |
5.89 |
6.17 |
6.42 |
| 11 |
5.14 |
5.67 |
6.00 |
6.28 |
6.50 |
6.67 |
6.97 |
7.25 |
| 12 |
5.83 |
6.39 |
6.78 |
7.06 |
7.28 |
7.47 |
7.81 |
8.08 |
| 13 |
6.56 |
7.17 |
7.56 |
7.83 |
8.08 |
8.31 |
8.64 |
8.92 |
| 14 |
7.31 |
7.92 |
8.33 |
8.64 |
8.92 |
9.14 |
9.50 |
9.78 |
| 15 |
8.03 |
8.69 |
9.14 |
9.47 |
9.72 |
9.97 |
10.33 |
10.64 |
| 16 |
8.81 |
9.50 |
9.94 |
10.28 |
10.56 |
10.81 |
11.19 |
11.53 |
| 17 |
9.56 |
10.29 |
10.76 |
11.12 |
11.41 |
11.65 |
12.06 |
12.39 |
| 18 |
10.34 |
11.09 |
11.58 |
11.95 |
12.25 |
12.51 |
12.93 |
13.27 |
| 19 |
11.12 |
11.91 |
12.41 |
12.79 |
13.10 |
13.37 |
13.80 |
14.16 |
| 20 |
11.91 |
12.72 |
13.25 |
13.64 |
13.96 |
14.23 |
14.68 |
15.05 |
| 21 |
12.71 |
13.55 |
14.09 |
14.49 |
14.82 |
15.10 |
15.56 |
15.94 |
| 22 |
13.51 |
14.38 |
14.93 |
15.35 |
15.69 |
15.98 |
16.45 |
16.84 |
| 23 |
14.32 |
15.21 |
15.78 |
16.21 |
16.56 |
16.85 |
17.34 |
17.73 |
| 24 |
15.14 |
16.05 |
16.64 |
17.08 |
17.44 |
17.74 |
18.23 |
18.64 |
| 25 |
15.96 |
16.90 |
17.50 |
17.95 |
18.31 |
18.62 |
19.13 |
19.54 |
| 26 |
16.78 |
17.75 |
18.36 |
18.82 |
19.20 |
19.51 |
20.03 |
20.45 |
| 27 |
17.61 |
18.60 |
19.23 |
19.70 |
20.08 |
20.40 |
20.93 |
21.36 |
| 28 |
18.44 |
19.46 |
20.10 |
20.58 |
20.97 |
21.30 |
21.84 |
22.28 |
| 29 |
19.28 |
20.32 |
20.97 |
21.46 |
21.86 |
22.20 |
22.75 |
23.19 |
| 30 |
20.12 |
21.18 |
21.85 |
22.35 |
22.76 |
23.10 |
23.66 |
24.11 |
| 31 |
20.97 |
22.05 |
22.73 |
23.24 |
23.65 |
24.00 |
24.57 |
25.03 |
| 32 |
21.82 |
22.92 |
23.61 |
24.13 |
24.55 |
24.90 |
25.48 |
25.95 |
| 33 |
22.67 |
23.79 |
24.50 |
25.02 |
25.45 |
25.81 |
26.40 |
26.87 |
| 34 |
23.53 |
24.66 |
25.38 |
25.92 |
26.35 |
26.72 |
27.32 |
27.80 |
| 35 |
24.38 |
25.54 |
26.27 |
26.82 |
27.26 |
27.63 |
28.24 |
28.72 |
| 36 |
25.25 |
26.42 |
27.17 |
27.72 |
28.17 |
28.54 |
29.16 |
29.66 |
| 37 |
26.11 |
27.31 |
28.06 |
28.63 |
29.08 |
29.46 |
30.08 |
30.59 |
| 38 |
26.98 |
28.19 |
28.96 |
29.53 |
29.99 |
30.38 |
31.01 |
31.52 |
| 39 |
27.84 |
29.08 |
29.86 |
30.44 |
30.90 |
31.29 |
31.93 |
32.45 |
| 40 |
28.72 |
29.97 |
30.76 |
31.34 |
31.82 |
32.21 |
32.86 |
33.38 |
| 41 |
29.59 |
30.86 |
31.66 |
32.26 |
32.73 |
33.13 |
33.79 |
34.32 |
| 42 |
30.47 |
31.76 |
32.57 |
33.16 |
33.65 |
34.06 |
34.72 |
35.25 |
| 43 |
31.35 |
32.65 |
33.47 |
34.08 |
34.57 |
34.98 |
35.65 |
36.19 |
| 44 |
32.23 |
33.55 |
34.38 |
34.99 |
35.49 |
35.91 |
36.59 |
37.13 |
| 45 |
33.11 |
34.45 |
35.29 |
35.91 |
36.41 |
36.83 |
37.52 |
38.07 |
| 46 |
33.99 |
35.35 |
36.20 |
36.83 |
37.33 |
37.76 |
38.45 |
39.01 |
| 47 |
34.88 |
36.25 |
37.11 |
37.75 |
38.26 |
38.69 |
39.39 |
39.96 |
| 48 |
35.77 |
37.16 |
38.02 |
38.67 |
39.19 |
39.62 |
40.33 |
40.90 |
| 49 |
36.66 |
38.06 |
38.94 |
39.59 |
40.11 |
40.55 |
41.27 |
41.84 |
| 50 |
37.55 |
38.97 |
39.85 |
40.51 |
41.04 |
41.48 |
42.21 |
42.79 |
| 51 |
38.44 |
39.88 |
40.77 |
41.44 |
41.97 |
42.42 |
43.15 |
43.73 |
| 52 |
39.33 |
40.79 |
41.69 |
42.36 |
42.90 |
43.35 |
44.09 |
44.68 |
| 53 |
40.23 |
41.70 |
42.61 |
43.29 |
43.83 |
44.29 |
45.03 |
45.63 |
| 54 |
41.13 |
42.61 |
43.53 |
44.22 |
44.77 |
45.23 |
45.98 |
46.58 |
| 55 |
42.03 |
43.52 |
44.45 |
45.15 |
45.70 |
46.17 |
46.92 |
47.53 |
| 56 |
42.93 |
44.44 |
45.38 |
46.08 |
46.64 |
47.10 |
47.86 |
48.48 |
| 57 |
43.83 |
45.35 |
46.30 |
47.01 |
47.57 |
48.04 |
48.81 |
49.43 |
| 58 |
44.73 |
46.27 |
47.23 |
47.94 |
48.51 |
48.98 |
49.76 |
50.38 |
| 59 |
45.64 |
47.19 |
48.16 |
48.87 |
49.44 |
49.92 |
50.70 |
51.33 |
| 60 |
46.54 |
48.11 |
49.09 |
49.81 |
50.38 |
50.86 |
51.65 |
52.28 |
| 61 |
47.45 |
49.03 |
50.01 |
50.74 |
51.32 |
51.81 |
52.60 |
53.24 |
| 62 |
48.36 |
49.95 |
50.94 |
51.67 |
52.26 |
52.75 |
53.55 |
54.19 |
| 63 |
49.27 |
50.87 |
51.87 |
52.61 |
53.20 |
53.70 |
54.50 |
55.15 |
| 64 |
50.18 |
51.79 |
52.80 |
53.55 |
54.14 |
54.64 |
55.45 |
56.10 |
| 65 |
51.09 |
52.72 |
53.73 |
54.48 |
55.09 |
55.59 |
56.40 |
57.06 |
| 66 |
52.00 |
53.65 |
54.67 |
55.42 |
56.03 |
56.54 |
57.35 |
58.01 |
| 67 |
52.91 |
54.57 |
55.61 |
56.37 |
56.97 |
57.48 |
58.31 |
58.97 |
| 68 |
53.83 |
55.50 |
56.54 |
57.31 |
57.92 |
58.43 |
59.26 |
59.93 |
| 69 |
54.75 |
56.43 |
57.48 |
58.25 |
58.86 |
59.38 |
60.21 |
60.88 |
| 70 |
55.66 |
57.36 |
58.41 |
59.19 |
59.81 |
60.33 |
61.17 |
61.84 |
| 71 |
56.58 |
58.29 |
59.35 |
60.13 |
60.75 |
61.28 |
62.12 |
62.80 |
| 72 |
57.50 |
59.22 |
60.29 |
61.07 |
61.70 |
62.23 |
63.08 |
63.76 |
| 73 |
58.42 |
60.15 |
61.22 |
62.01 |
62.65 |
63.18 |
64.04 |
64.72 |
| 74 |
59.34 |
61.08 |
62.16 |
62.96 |
63.60 |
64.13 |
64.99 |
65.68 |
| 75 |
60.26 |
62.02 |
63.10 |
63.91 |
64.55 |
65.08 |
65.95 |
66.64 |
| 76 |
61.18 |
62.95 |
64.04 |
64.85 |
65.50 |
66.03 |
66.91 |
67.61 |
| 77 |
62.10 |
63.88 |
64.99 |
65.80 |
66.44 |
66.99 |
67.87 |
68.57 |
| 78 |
63.03 |
64.82 |
65.92 |
66.74 |
67.40 |
67.94 |
68.82 |
69.53 |
| 79 |
63.95 |
65.75 |
66.87 |
67.69 |
68.35 |
68.90 |
69.78 |
70.49 |
| 80 |
64.88 |
66.69 |
67.81 |
68.64 |
69.30 |
69.85 |
70.74 |
71.45 |
| 81 |
65.80 |
67.62 |
68.76 |
69.59 |
70.25 |
70.80 |
71.70 |
72.42 |
| 82 |
66.73 |
68.56 |
69.70 |
70.54 |
71.20 |
71.76 |
72.66 |
73.38 |
| 83 |
67.66 |
69.50 |
70.64 |
71.48 |
72.16 |
72.71 |
73.62 |
74.34 |
| 84 |
68.59 |
70.44 |
71.59 |
72.44 |
73.11 |
73.67 |
74.58 |
75.31 |
| 85 |
69.51 |
71.38 |
72.54 |
73.39 |
74.06 |
74.63 |
75.54 |
76.28 |
| 86 |
70.44 |
72.32 |
73.48 |
74.33 |
75.02 |
75.58 |
76.51 |
77.24 |
| 87 |
71.37 |
73.26 |
74.43 |
75.29 |
75.97 |
76.54 |
77.47 |
78.20 |
| 88 |
72.30 |
74.20 |
75.38 |
76.24 |
76.93 |
77.50 |
78.43 |
79.17 |
| 89 |
73.23 |
75.15 |
76.32 |
77.19 |
77.88 |
78.46 |
79.39 |
80.14 |
| 90 |
74.17 |
76.09 |
77.27 |
78.14 |
78.84 |
79.42 |
80.36 |
81.10 |
| 91 |
75.10 |
77.03 |
78.22 |
79.09 |
79.79 |
80.38 |
81.32 |
82.07 |
| 92 |
76.03 |
77.97 |
79.17 |
80.05 |
80.75 |
81.34 |
82.28 |
83.04 |
| 93 |
76.97 |
78.91 |
80.12 |
81.00 |
81.71 |
82.30 |
83.25 |
84.01 |
| 94 |
77.90 |
79.86 |
81.07 |
81.96 |
82.67 |
83.26 |
84.22 |
84.97 |
| 95 |
78.84 |
80.80 |
82.02 |
82.91 |
83.63 |
84.22 |
85.18 |
85.94 |
| 96 |
79.77 |
81.75 |
82.97 |
83.87 |
84.58 |
85.18 |
86.14 |
86.91 |
We recommend that you monitor port usage regularly and plot it
over time in order to anticipate traffic needs. We also recommend
that you observe port capacities on a weekly basis on new systems
or when you are adding new subscribers, and on a monthly basis on
older systems.
Spotting potential system problems
In addition to helping determine GOS and port usage, the Feature
Daily and Feature Hourly Traffic Reports provide statistical information
that is useful for spotting potential problems and for evaluating
how your messaging system is actually used. This information includes
the:
- Number of subscribers administered in the messaging system
- Total call answer and voice session usage time
- Number of login attempts and abandoned calls
- Number of voice mail, call answer, broadcast, login announcement,
urgent, and private messages sent
- Average storage time of voice mail and call answer calls
- Types of messages, including voice, text, and fax components
and binary attachments
Load reports
The Load daily or hourly traffic reports display information about
the number of calls handled by each active port for up to 32 consecutive
days or 192 consecutive hours, respectively.
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Note: The Maximum Simultaneous IMAPI Sessions in
Use field in the Load daily or Load hourly traffic reports
provides valuable information about system load, but the data
should not be used for GOS calculations.
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Spotting switch problems
The average number and duration of the calls that are made to
the messaging system during the period is reported. These numbers
may indicate a problem at the switch with either port coverage or
distribution if one port is overloaded and other ports are underloaded.
Spotting threshold
problems
Threshold exceptions indicate that subscribers tried to use more
message or list space than is available and that warnings were issued.
These exceptions can be the first indication that you need to change
certain information contained in other screens.
If you notice a large number of threshold exceptions for lists,
it may mean that you initially miscalculated the maximum number
of lists per subscriber. You can increase the number of lists assigned
to each subscriber through both the System-Parameters Limits. You
can also ask subscribers to delete old or unnecessary lists.
The upper and lower limits for message space are shown on the
screen. If the limits are consistently exceeded, you can do any
or all of the following:
- Increase mailbox size for an individual subscriber by editing
the subscriber's class-of-service. See Editing
a class-of-service or the Mailbox
Manager User Guide for more information .
- Decrease message retention time on the COS screen. This action
limits the length of time that the messaging system retains messages
within subscribers' mailboxes, resulting in the more frequent
deletion of old messages.
- Raise the thresholds administered on the System-Parameters Thresholds
screen.
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