Contents Telektronikk - Telenor

Table 8 Call holding times (in minutes) – Interval 3: Saturdays and Sundays
– both domestic and international). We
believe that the price is the most important
factor here, but not the only one.
The results also show large differences
between mean holding times for different
categories. Paging is the service with the
shortest holding time, while special services
have the second shortest holding
time. Calls to mobile telephones and fax
also have relatively short duration. Mean
holding time for calls to Toll-free numbers
is close to that for long distance
domestic calls.
3.6 Other results
3.6.1 Number of call attempts and
relation between incoming
and outgoing traffic
Number of call attempts of both incoming
and outgoing calls were registered by
using TELMAX in Period 3 (25.11.91 –
29.11.91) between 0700 and 1900. By
comparing the statistics registered by
TELMAX with the charging files from
the same period, we also found the number
of successful outgoing calls2 , and the
incoming and outgoing traffic.
Figure 10 shows the average number of
call attempts, and Figure 11 shows the
incoming and outgoing traffic, both registered
per 15 minute intervals, in Period
Period 1 Period 2
Category # obs Mean S.D. C.V. Max. # obs Mean S.D. C.V. Max.
Local 1974 3.52 7.01 1.99 114.1 3023 3.64 6.79 1.87 130.9
Neighb.counties 18 4.93 8.13 1.65 27.8 35 5.36 7.28 1.36 36.7
Long distance 424 10.43 31.74 3.02 518.9 619 9.53 13.02 1.37 145.9
Universities 6 1.92 1.84 0.96 5.4 8 3.80 4.39 1.16 13.9
Univ. (fax) 3 2.18 2.75 1.26 5.4 3 4.12 1.21 0.29 5.3
International 139 5.77 9.44 1.64 56.2 135 9.45 19.22 2.03 150.7
Mobile 29 3.45 5.46 1.58 25.4 19 1.56 1.02 0.65 3.4
Paging 17 0.32 0.14 0.44 0.7 54 0.35 0.13 0.37 0.7
Special serv. 196 0.90 1.29 1.43 7.5 208 1.07 1.99 1.86 20.0
Toll-free 2 10.20 4.46 0.44 13.4 1 6.15 - - 6.15
Total 2799 4.49 14.11 3.14 518.9 4094 4.56 8.86 1.94 150.7
2 Due to the limitations of the registration
tools we were unable to register the
number of successful incoming calls.
3 between 0700 and 1900. The total
number of call attempts, the percentage
of outgoing calls being answered, and the
traffic are shown in Table 9.
Figure 10 and Figure 11 show that both
in terms of the number of call attempts
and the traffic intensity, the 24-hour profiles
for incoming and outgoing calls are
quite similar.
Table 9 shows that the number of outgoing
call attempts is approximately 40 %
larger than that of incoming call
attempts. Figure 10 shows that this is true
for the whole observation period. However,
the traffic registered during the
same period actually shows that the outgoing
traffic is less than the incoming
traffic.
There are two possible explanations to
this phenomena:
1 outgoing calls have a lower success
rate than that for incoming calls
2 mean call holding time for outgoing
calls is shorter than that for incoming
calls.
Since we neither could register call holding
time nor success rate for incoming
calls, we cannot give any final conclusion.
But we believe that both explanations
could be true.
We have reason to believe that the success
rate for incoming calls is higher than
that for outgoing calls, since the difference
between outgoing and incoming call
attempts is as big as 40 %, while the reg-
Number of call attempts
Erlang
1200
1000
800
600
400
200
200
160
120
0
0700 0900 1100 1300 1500 1700
incoming calls
outgoing calls
total number of calls
80
40
Figure 10 Number of call attempts per 15 minute
intervals
0
0700 0900 1100 1300 1500 1700
incoming traffic
outgoing traffic
total traffic
Figure 11 Traffic per 15 minute intervals
127