[Asterisk-Users] Newbie Question-Looking for Feedback
M. Matt Colgin
asterisk at digitalcandle.com
Wed Jan 7 18:37:52 MST 2004
Goal
====
Provide phone service using the Asterisk system running on standard PC
equipment for four concurrent phone conversations. Calls will come into the
Asterisk system where they will be answered via VoIP. VoIP will be provided
via the internal 100mbit/s ethernet network and optionally from the internet
via a T1 line providing 1.5mbit/s.
Setup
=====
We're a small business inducted to the Asterisk world in an attempt to
provide a "real" phone system to customers and our remote employees.
The #1 attraction to Asterisk is it's low cost, feature set and the fact
that it's opensource (linux).
In a previous email, I asked for a bit of direction in what type of
configurations would be best suited for our environment. I've taken as much
feedback and suggestions and formulated three different configurations that
seem to solve the goal. Each of the configurations seem to advantages and
disadvantages.
Questions
=========
The number one question for each configuration is "Will this work?" and
"Does anyone else run this configuration in their environment?"
(Configuration Diagrams are below the Questions)
Configuration #1
----------------
- Can our telecom company provide two ISDN BRI lines. Each ISDN line
providing 2 channels of 64kbit/s?
- What manufacturer/model of ISDN adaptor is best supported by Asterisk?
Disadvantage: Seems to be a rare configuration based on what seems to be
antiquated technology.
Advantage: Cost. I estimate the two ISDN BRI cards to run $100/each with
minimal investment in the telecom provisioning.
Configuration #2
----------------
- Are there cheaper, less extensive channel banks which might be more cost
effective for our limited scalability needs?
Disadvantage: Cost. The channel bank runs about $1700-$2000 retail with the
8-port FXO service card.
Advantage: Future Scalability. However, I don't perceive servicing
additional phone lines and if we did, it would most likely be done by
pulling some data channels off one of the existing T1s and sending it
directly to the Digium T100P.
Configuration #3
----------------
Advantage: Cheap
Disadvantage: Suspected Reliability. In reading posts from other users of
these cards, there appears to be a serious chance of IRQ conflicts and
"echo" problems using this many single port FXO devices in a single machine.
Digium does not currently produce a >=2 port FXO version of the card.
CONFIGURATION Diagrams
======================
1. Switch the four POTS lines to 2 ISDN BRI lines.
Install 2 cards which are 2-Port ISDN BRI Adaptors.
ISDN BRI ISDN BRI
Line #1 Line #2
| |
+----+-------+
|
v
AVM or Eicon
2 Port Card
2. "Bundle" the four POTS lines with a channel bank (creating a T1 with 4
channels used)
Using a T1 cross-over, connect the channel bank to the Digium T100P
POTS 4-Lines
| | | |
+-+++-+
|
v
Carrier Access
ADit 600
|
v
Digium T100P
3. Take each of the four POTS lines and simply plug them into four distinct
Digium Wildcard X100P adators.
Downside is that this isn't a recommended procedure as there might be IRQ
conflicts and "echo" induced by the multiple adaptors.
POTS-1 POTS-2 POTS-3 POTS-4
| | | |
v v v v
X100P X100P X100P X100P
| | | |
+-------+---+---+-------+
|
v
TDM400P 4 Port (to make analog lines from *PBX)
Hard Phones: Snom 200, Grandstream ($70), Cisco ($$)
Soft Phones: X-Lite, X-Pro
> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com
> [mailto:asterisk-users-admin at lists.digium.com] On Behalf Of WipeOut
> Sent: Wednesday, January 07, 2004 1:32 PM
> To: asterisk-users at lists.digium.com
> Subject: Re: [Asterisk-Users] Newbie Question-Looking for Feedback
>
> M. Matt Colgin wrote:
>
> >I've been looking at Asterisk for a replacement for our
> phone system and I'm
> >hoping someone can help validate my assumptions.
> >
> I'll try.. :)
>
> >
> >We have 4 analog lines coming into the building. These lines
> are simple POT
> >lines and we have them in a "hunt group" with Verizon so
> that when a single
> >phone number is dialed, the first line is rang, if that line
> is busy it will
> >ring the second line, and so on.
> >
> >I would like to put together an Asterisk system to handle
> these lines and
> >allow us to do VoIP, call queuing, voice menuing, etc. In
> looking at the
> >product offerings of Digium, it appears that I need 4
> Wildcard X100P's and 1
> >Wildcard TDM400P 4-Port. For VoIP work, I'm looking for any
> recommendations
> >that can be made. My first priority is to support a user in
> New Zealand
> >talking to our phone system in the US, but there could be
> another 2 I'd like
> >to support in the US (all on cable modems with the typical
> capped 30KB/s
> >upload). I'd like for it to work very well with the Asterisk
> PBX and be as
> >simple as plugging in a ethernet cable or even support
> 802.11b/g with little
> >to no configuration.
> >
> >In addition, I'm curious on other people's experience with
> software based
> >VoIP phone. Specifically, it appears that a good amount of
> amount could be
> >saved by using software based phones inside the building,
> thereby negating
> >the need to purchase 3 hard VoIP phones and the Wildcard
> TDM400P. Can anyone
> >recommend a good software package, that is fairly idiot
> proof and would work
> >well for a small call-center with temp/minwage employees?
> >
> >
> >To Summarize:
> >- Can and does it make sense to purchase 4 Wildcard X100P's?
> >- Can and does it make sense to purchase 1 Wildcard TDM400P (4-Port)?
> >
> I will answer these together, the recomendation is typically
> not to go
> above 3 cards in a system which means that you could give 5
> cards a go
> but chances are you are not going to have a happy time with it..
>
> My suggestion would be to either use a channelbank and a T100P or the
> simpler solution convert your 4 analog lines to 2 ISDB BRI lines and
> then get a 2 port AVM or Eicon ISDN card..
>
> >- What VoIP hard phone works best with Asterisk? Are there
> WiFi ones that
> >are less than $100?
> >
> My personal favorite in terms of both cost and performance
> would have to
> be the Snom 200.. Other options are the Grandstream (cheapest
> there is),
> the Cisco(a little pricey), the Snom 105 and no doubt a few others..
>
> A Grandstream costs about $75 and AFAIK its still the cheapest so I
> would have to say No, you will not likely get a WiFi VoIP phone for
> under $100..
>
> >- How much bandwidth does VoIP require? Will cable modem
> users with a max
> >30KB/s upload ok?
> >
> The bandwidth requirement is dependent on the codec but 30KB/s should
> hande any codek no problem.. the bigger problem you will have
> between NZ
> and the US is latency which is really annoying when trying to
> transfer
> realtime data..
>
> >- What VoIP soft phone works best with Asterisk?
> >
> I have found X-Lite or X-Pro to be the best..
>
> >
> >Also:
> >- What kind of uptime are people experiencing?
> >
> I have over 100 days continuous, with reboots to apply
> patches.. Others
> on the list have said thay have over a years uptime..
>
> >- How much system load will be needed for 4 concurrent VoIP
> conversations?
> >
> I have a P2 400 development server and have done 4 concurrent ( thats
> all I have ) VoIP sessions.. My production server is more
> powerful and i
> have not really looked at the number of concurrent sessions but its
> never really broken a sweat..
>
> >- What kind of gotcha's have people had that would be good
> for a newbie to
> >know?
> >
> Becasue the software is free does not mean that the system will be,
> there are many really cheap off the shelf analog only PBX's out there
> that will be much cheaper.. the advantage to * is all the
> features you
> get and the VoIP support.. and of course the satisfaction
> when its all
> working.. Of course if it crashes you better run cos your
> users will be
> hunting you down.. :)
>
> >
> >
> >Thank you in advance,
> >
> >
> Hope it helped..
>
> Later..
>
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