It really depends on the user's voicemail usage, the maximum you can get with one Unity server is 72 ports, if you configure couple of them as MWI ports, it will provide 70 concurrent voicemail calls, which should be enough.
We are currently doing a Unity build in our Lab to evaluate when/how to replace our current Octel voicemail system (integrated with CCM 3.3.(4)). I have been reading a Unity integration guide that has the following details;
"As a general guideline, set Message notification, Dial out MWI and Trap connections on approximately 25 percent of the ports"
"As a general guideline, set Answer calls on approximately 75 percent of the ports"
So I have been going along thinking we would have around 54 ports (out of 72) that could be used to provide concurrent voicemail calls.
Am I confused (probably) or just missing the point completely?
Thanks for your help!!
Look at it this way. How many Octel ports are you using now? If your Octel has 50 ports for VM only, then you should look at a usuage report for the Octel. Are all 50 Ports being used all the time, or is it only used at 25 percent? Is the Octel being used as an Auto Attendent?
For Unity, create equal ports from Octel you have now, but look at what is utilized. If you are going to be using Unity as an Auto Attendent for your main number AND VM.. and your call volume is high, you will will need more ports to answer those calls and route. Each time a Call Handler picks up a call on Unity, it uses a Port, just like VM. So you need to calculate this also. If you use up 72 ports, you will need to route your incoming calls to another Unity server dedicated just for Call Handling (if your volume is huge).
The 25 percent for MWI is correct.
Hope this helps in your considerations on sizing.
Hi Tommer ... Thanks for your Great answer. I think we will be OK with the 75/25 ratio between MWI and answer ports, as we currently have only 40 ports on our existing Octel. We rarely if ever have "all ports busy" at this time,so we should be good to go with the 72 available Unity ports.My main concern is with future expansion, in case we eventually add on our Student Residence buildings which would add 1000 plus users.What would be the minimum number of MWI ports we could get away with before adding the additional Unity server for call handling?
Thanks again for your help!!
Another thing to consider IF you are planning to go unified messaging versus VMO (voicemail only). In unified messaging installations, voice message playback from Outlook to PC speakers is a user option. This does not require a voice port. When we train our customers, we demonstrate how to switch between phone and speaker playback. So if you are going UM, your initial port utilization following enrollment may decrease after a week or two as users learn their options. For example, we have a 700+ user base on one of our Unity servers with 24 ports and several auto attendants. Our high usage is around 9-10 ports concurrent.
Thanks so much for taking the time out of your day to respond to my question. I have read many of your answers over the past months and they are always well reasoned and extremely thoughtful. Our current "test" build is VMO but I'm guessing that when we do our production build it will be Unified. I have not done too much reading on the Unified messaging model and was not aware of the difference in port usage. I will do some reading to see if I can get up to speed on these items. Our College is a
Lotus Notes environment and that integration scares the heck out of me, but I'm hopeful that everything
will come together.
Thanks again Ginger!!
Take care. Rob
Well, look at the Unity table for amount of users you can have one Unity Server...
If you configuration 3, you can have up to 7500 users. But if you only 72 ports for VM on that one server, it might be a little tricky providing VM. Like Ginger said, if you were using UM, the port usage drops because they are "listening" to their VMs with their outlook client. Does not use a port.
If you plan on adding 1000 users in the next 12-24 months, I would just go ahead a build another Unity server, but divide your ports around to spread the cost. If you were to put 3000 users one server and you had 72 ports open, I think you would pushing your SLA's slightly. Ports would be utilized at 90 pecent. Your MWI's would be late turning on lights to your subscribers phone. Typically, people expect that if a message was left, the light turns on within 10 seconds or less. (less being better of course) If your MWI ports are busy taking calls for VM, Unity has to wait for a port to open up, then ring CCM on a open port to turn the MWI on.
If you rarely have all ports busy now at 40, you should be ok. And if this system isused for only VM, not call handlers, at 72 ports and 3000 subscribers... you may be pushing it. If it was UM setup, no problem. If you stick with VM only setup, break it up into another Unity server. I havent seen a best practice for VM only setup with over 72 ports one server, and 72 ports on the next server, etc. I would think it would be fine, just have to program CCM for certain profiles. If 2000 phones profiles all role to Unity 1, then the next 2000 phone setup profiles, should roll to Unity 2. Make sense? (changing the pilot numbers for VM.)
Of course, this is a forum, and I'm not an expert. But feel free to dig up some more research on this. In theory, I think this is correct, but there may be other ways to do this.
Since you are dealing with Student Residence... if they are the freshman class, give them the lowest SLA's... (jokes)
Hey Tommer ... Thanks for getting back to me so quickly!! Don't sell yourself short about being an expert.I have read many of your answers recently in this forum and I can tell you know what you are doing.I will read the link you referred to over the weekend and if I have more questions will post them here over the coming weeks.I agree with you that our future production build should be done with the Student Residences in mind right from the start (even the Freshman).I have been an Octel system admin for many years, so this Unity stuff seems quite different.Hopefully with more study it will all come together.
Thanks again for your help Tommer!
Have a good one! Rob