Advice for 40 phone office

Discussion in 'General' started by downtownpc, Aug 16, 2010.

  1. downtownpc

    Joined:
    Aug 16, 2010
    Messages:
    4
    Likes Received:
    0
    I'm a 20+ year IT guy that know just enough about to be dangerous. I setup my VoIP a few years ago and love it - it's not Elastix but it will be soon. In the mean time I've been asked to setup a short term (1 week) office with 40 IP phones (10x the # of phones in my office). Not sure if this is the place to ask these questions but I was hopping to get a little advice from those with more experience.

    I have a couple 24 PoE switches and the phones are on the way but I was hoping for a little advice. In no particular order.

    1.) I'm thinking about using an new Dell Zino or if need be I have a Dell T105 server - I would think both would be overqualified... right?

    2.) I guess I'll need 40 G.729 Codec's but as I understand they are locked to the PBX and I won't be able to use them again... or is there a way to move them to a new server when needed?

    3.) I'm considering voip.ms for termination and DID's - anybody love or hate them?

    4.) I was planning on putting the PBX behind the router and using IAX trunks because they seem more NAT friendly but SIP seems more common and seems preferred by most - any reason I should use SIP over IAX trunks?

    Thanks,
    -Dane
     
  2. Awesomo

    Joined:
    Nov 5, 2009
    Messages:
    32
    Likes Received:
    0
    1.) I'm thinking about using an new Dell Zino or if need be I have a Dell T105 server - I would think both would be overqualified... right?

    Depends, If you will be allowing more than 10ish concurrent calls transcoded to g729, You will need the Dell t110 (replaced the t105). g729 is processor intensive

    2.) I guess I'll need 40 G.729 Codec's but as I understand they are locked to the PBX and I won't be able to use them again... or is there a way to move them to a new server when needed?
    Digium makes the license key specific to your EXACT hardware configuration. If you add a pci card, change the amount of ram, etc... you will have to request a change. Depending on the mood of the person you get, they "may" make a change for you. Right off the bat they allow the license to be used with two servers (a production server and a test server) or in the event you change hardware ONCE, you wouldn't need to request a change. But do you really need a license? If the phones you choose (Aastra phones and their XML scripts are the best Asterisk phones out imho) support g729 and you run them all at g729, then the server wouldn't have to do any trans coding which doesn't require a license.

    3.) I'm considering voip.ms for termination and DID's - anybody love or hate them?
    No experience with them, they are Canadian, and I like keeping my phone service in the same country as me. I can recommend flowroute though.

    4.) I was planning on putting the PBX behind the router and using IAX trunks because they seem more NAT friendly but SIP seems more common and seems preferred by most - any reason I should use SIP over IAX trunks?
    If the provider supports IAX, by all means go IAX. You will only need to open a single port for IAX and it doesn't make asterisk suffer from the SIP bug. In case you didn't hear about it, if Asterisk has a list of sip trunks and they all go offline, or your internet goes out, Asterisk ceases to work. All of your internal extension's wouldn't even be able to call each-other. There are workarounds like a caching DNS server, but why go through all that if your provider supports IAX?
     
  3. downtownpc

    Joined:
    Aug 16, 2010
    Messages:
    4
    Likes Received:
    0
    Thanks that's a huge help. If I could ask for further clarification...

    Are you saying that if the phone supports g729 and my provider supports g729 then I can just use it (legally) w/o purchasing licenses? The decision was already made to use Polycom IP 335 phones and supports g729 but it seems to me almost all phones do? So what would be an occasion where I would need to buy a license?

    Does this also avoid cpu intensive transcoding?

    Again thank you very much!
    -Dane
     
  4. Awesomo

    Joined:
    Nov 5, 2009
    Messages:
    32
    Likes Received:
    0
    Yes and no. Sorry, but I forgot about one little gotcha (ok, big gotcha).

    Yes, you will be able to make phone calls and do very basic functions, legally.

    BUT guess what codec is used to handle other asterisk functions like voicemail, ivr prompts, conference rooms, etc... g711 of course.

    So that DOES require a license because the g729 phones would have to transcode to g711 to access those Asterisk features. There are ways to get it working in g729 mode, but at $10 a channel, HA. Where's my credit card number?

    Now the question is "How many licenses do I need to purchase?"

    Set all your phones to use g711 only and you won't have any trans-coding happening between extension calls. That leaves max concurrent trunk calls. You need one $10 license for every concurrent call that will occur.

    Say you want the capability to have 20 concurrent outside calls at once, you'll need 20 licenses. Simple. Thanks for asking for clarification, I never would have remembered until questioned.
     
  5. dicko

    Joined:
    Oct 24, 2008
    Messages:
    4,099
    Likes Received:
    0
    (to be pedantic, Asterisk uses slin and not g711 as it's base audio stream, but the answer is essentially correct

    rasterisk -x "show translation"

    will show the "cost" and availability of it's internal translation process, you got a '-' you can't do it)
     
  6. downtownpc

    Joined:
    Aug 16, 2010
    Messages:
    4
    Likes Received:
    0
    Thanks once again,

    Very interesting... So I need all 40 phones to be able to call at the same time but very limited on the other features. It's short term production and we haven't even decided if we are going to use vm,ivr, or conference. Could I use all g729 to maximize bandwidth and buy 10 or so g729 licenses for the occasional IVR or such?

    -Dane

    -Dane
     
  7. dicko

    Joined:
    Oct 24, 2008
    Messages:
    4,099
    Likes Received:
    0
    Another legal licensor is Howler

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

    they have a slightly cheaper and definitely more mutable licensing agreement than Digium

    I have never used them.

    dicko

    [edit]

    never mind, I checked my own post and they went belly up last month. (maybe they got busted :) :) )
     
  8. Awesomo

    Joined:
    Nov 5, 2009
    Messages:
    32
    Likes Received:
    0
    That's the idea. Just takes a bit of work forcing g729 on everything. The worst that could happen is you needing to drop another $300.

    As to Howler tech, heard of them, never used them either, but they screwed something up because their company closed a few weeks back.
     
  9. downtownpc

    Joined:
    Aug 16, 2010
    Messages:
    4
    Likes Received:
    0
    Thanks! Excellent info. I'll test it out over the weekend.

    -Dane
     

Share This Page