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T1 line 1.5mb up n down/How many agents can dial on this?

PostPosted: Wed Nov 11, 2009 1:36 pm
by ums2009
I am getting a t1 line installed and i would like to know how many agents I can have dialing through this connection? My server is in a remote location with plenty of bandwith(fios 50/20). Please any advice would be great.

PostPosted: Fri Nov 13, 2009 2:00 am
by williamconley
"rough" rule of thumb:

ulaw connection = 100k per call
g729 connection = 10k per call

don't forget that the connection is shared, and there's overhead involved in making the connections (and g729 is very touchy, when it gets tight g729 gets very bad very quickly and does not recover well)

PostPosted: Tue Nov 17, 2009 3:31 pm
by billybobxm
i installed a system at an office with 2 bonded T1's and they were able to get about 20 agents on with the ratio set at 4 on 729, we started having problems at over 100 calls. I am in the process of trying to install the dialer remotely and I am having all sorts of problems I believe are all bandwidth related. We can get 15-16 agents working then if any more login then it starts to have problems. I can't pin point the problem i have moved it around to 3 different colo's and i have it on a 10 mb shared with other phone systems and it seems to work but we are being limited by the other usage on the network. Let me know how it goes for your install I am curious how many agents you can get working remotely.

PostPosted: Tue Nov 17, 2009 4:28 pm
by williamconley
2 bonded T1s=3Meg

20 agents 4:1 = 80 calls (MAX), but you have a problem when calls go over 100? with 16 agents? are you now up to 7:1 ratio as opposed to 4:1?

10Meg (shared = somewhere between 10k & 10Meg, kinda inconclusive, not sure that's helpful especially since there was no mention of 10Mx??M)

sounds like you're having a heckuva day ...

Remember: Just because you manage to fit more calls into the "mix" by switching to g729, does not mean you've magically increased your capacity.

The cost for g729 is CPU. The dialer has to "transcode" those calls, which is a lot of work, BTW, and thus uses quite a bit of CPU power ....

If it goes too far (too much work), call quality will suffer dramatically when you hit the barrier. Check your server load which is available through several channels: (just a few)
    at the CLI you can use "uptime"

    or in the GUI at "ADMIN->SERVERS" then choose your server and it's on the 3rd or 4th line

    *I* prefer htop, it shows each cpu individually

PostPosted: Tue Nov 17, 2009 4:37 pm
by billybobxm
i am not having problems with call quality it is an issue with agents using the webpage and logging into the webpage. The connection is very weak and at times it will timeout.

And I am obviously talking about 10mb internet connection.

PostPosted: Wed Nov 18, 2009 12:19 am
by williamconley
So what do you mean by "weak"? (if it's something other than timeouts...)

Do you have QOS on and your router is "prioritizing" the http packets as "Low" so they get dropped? (to keep the voice quality high ...)

Is the issue at the agent's router or the vicidial server's router (you said colo, right?)?

If it's the agent's ... you could install a cheap DSL line for the browsers and probably get what you need. They generally have excellent DOWNLOAD, which is primarly all the browsers need. Take a little routing magic, but it's been done.

PostPosted: Wed Nov 18, 2009 11:23 am
by billybobxm
okay well the problem was the bandwidth at the colo it was killing the system. I had them open up the pipe and allow us to run 100mb to see where we were at and with 24 external agents running on a 4 to 1 ratio using g729 total bandwidth usage is hovering around 4 to 5mb. So this is a lot more than i was thinking we were going to be using.

PostPosted: Wed Nov 18, 2009 11:54 am
by williamconley
ok, i'm catching up ... but you said you had 10meg available and your usage was hovering around 4-5 meg ... so i've lost track of the problem ...

PostPosted: Wed Nov 18, 2009 12:48 pm
by jepps3
Dumb question.....Do you have to pay to use g729?

PostPosted: Wed Nov 18, 2009 1:54 pm
by williamconley
Yes.

The easiest way to get it is to purchase licenses from Digium ($10/channel). Installation is a bit freaky, but they have directions.

Details on the rules:

http://www.voip-info.org/wiki/view/Aste ... +Licensing

PostPosted: Wed Nov 18, 2009 7:08 pm
by mflorell
You can also get G729 licenses from Howler Technologies:
http://www.howlertech.com/products/howlets/