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# Trunking Capacity

Viewing 4 posts - 1 through 4 (of 4 total)
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• #68344
Jeff
Guest

I am looking to groom some trunking between 2 switches I have. When attempting to do the formulas for determining Erlangs the number of trunks it is telling me I need is no where close to what I have and they are at 80% capacity. Looking at the statistics I have 123047 CCS in a 24hr period. This gives me 142.42 Erlangs. With that number I come up with 161 trunks needed @ 1%. I have 792 trunks configured for this with 80% capacity so I’m obviously doing something wrong with my calculations

#68345
pix
Guest

hi jeff,

123,047 CCS over 24 hours, that’s nothing. As you said, that’s only 142.5 erlangs !

So there is a glitch somewhere, le’s see…

1/ Why do you think you need to increase your capacity ?

2/ How many channels in one of your trunks ?

There is, it seems, a mistake of a factor “4”. So I believe that one you say “trunk”, you actually refer to an E1 nibble (16kb/s)
While a call in your system seems to be actually using 64kb/s timeslots.
Therefore you need 161 * 64kb/s, which translates in 161*4 “trunks”, which is 644 trunks. Now, there is a 80% load limit, so you actually need 805 trunks (644/0.8).

Let me know what you think.

Cheers,
pix

#68346
Jeff
Guest

Yes when I say trunks I am referring to a DS0 (64kb/s). When I come up with the number of circuits needed is this referring to 16kb/s circuits as you mentioned?

#68347
pix
Guest

it really looks like you are counting your trunk as if they were 16kb/s.

in other words, it looks like 1 call in your system is using 4 of your trunks.

your numbers are not adding up, just trying to give you some pointers, but it’s up to you to investigate 😉

cheers
pix

Viewing 4 posts - 1 through 4 (of 4 total)
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