Is there a formula to calculate % usage on a trunk group. Example: Trunk Group has 140 lines, carries avg 2400 calls per day. I know avg hold time, etc factors in but in this instance do not want to factor anything in except the # of lines and # of calls carried in a day. Need to determine ballpark % usage on trunk group on a daily basis. Any info appreciated. Thanks
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Determining daily trunk group % usage
- Thread starter navy1
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Peg counts are useless, what you need are call seconds
One standard value is CCS - Centum Call Seconds. In traffic engineering, hundred (centum) call seconds. One hour contains 3600 call seconds (60 seconds times 60 minutes), or 36 CCS.
Lets say for the sake of argument that each call was exactly 5 minutes long and that the 2400 calls were over a period of 8 hours
300 calls / hour * 300 seconds / call = 9000 call seconds for the group/ hour
140 trunks * 3600 seconds = 504000 call seconds of availability
9000 / 504000 * 36 = .64285 CCS for the trunk group
You then get into grades of service. This determines the average amount of time that no trunks are available for processing calls. Typically measured during peek traffic hours
P1 grade of service says that 1% of the time all trunks are in use - This is considered good
- With your average of 300 calls per hour, let's say that peaks at 600 in your busiest hour
- For a P1 grade of service, all of your trunks would need to be in use for a total of about 36 seconds during the hour
- If all of your trunks were in use for 36 seconds you would consume 5040 call seconds
- considering your average complete hour only has 9000 seconds of usage (based on 5 minute call durations which might be high for all I know), I would say with some confidence that you have way too many lines.
You have too many trunks my friend.
**********************************************
What's most important is that you realise ... There is no spoon.
One standard value is CCS - Centum Call Seconds. In traffic engineering, hundred (centum) call seconds. One hour contains 3600 call seconds (60 seconds times 60 minutes), or 36 CCS.
Lets say for the sake of argument that each call was exactly 5 minutes long and that the 2400 calls were over a period of 8 hours
300 calls / hour * 300 seconds / call = 9000 call seconds for the group/ hour
140 trunks * 3600 seconds = 504000 call seconds of availability
9000 / 504000 * 36 = .64285 CCS for the trunk group
You then get into grades of service. This determines the average amount of time that no trunks are available for processing calls. Typically measured during peek traffic hours
P1 grade of service says that 1% of the time all trunks are in use - This is considered good
- With your average of 300 calls per hour, let's say that peaks at 600 in your busiest hour
- For a P1 grade of service, all of your trunks would need to be in use for a total of about 36 seconds during the hour
- If all of your trunks were in use for 36 seconds you would consume 5040 call seconds
- considering your average complete hour only has 9000 seconds of usage (based on 5 minute call durations which might be high for all I know), I would say with some confidence that you have way too many lines.
You have too many trunks my friend.
**********************************************
What's most important is that you realise ... There is no spoon.
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