2U Linux PBX and firewall servers

[pcunite]

I need to build two 2U rack mount Linux boxes. One will have Snom ONE PBX (same as PBXnSIP) installed and the other box will have some router/firewall package (IPCop, ClearOS, etc.) installed. Prefer the same hardware for both to keep things simple.

Usage:
The PBX will have at most 50 simultaneous calls using G.722 and G.711u codec. The router will have at most 50 PC's doing simple web browsing. Naturally calls and surfing will overlap at times. The router will perform QoS/Shaping for the VoIP connections.

I would appreciate your opinion on the hardware I've chosen. Is the CPU powerful enough? I'm hoping it is overkill actually. Anything I need to be aware of?

Hardware $500 budget per box:
Case - iStarUSA
MB - ASRock H77M
CPU - Intel G2020
RAM - Crucial 4GB
PSU - Corsair CX430
SSD - Crucial M4 64GB
NIC - Intel PRO/1000

 

[metril]

What is your WAN connection speed? Will this be deployed on a gigabit network? Will you be using VLANS?

Your usage description does not give us the whole picture. Also, I would avoid Realtek. Realtek NICs do not really offload the network stack. Rather, your processor would be doing it all. I would pick up a supermico matx board. The x9scm-f has IPMI for remote management and has 2 Intel NICS. You can stick an i3 in one. This would up your cost per box by $200.

You do not want an SSD in these boxes. The logging will wear away the SSD in no time. You can get a laptop hard drive.

QoS is a lot more CPU intensive than you think.

 

[pcunite]

What is your WAN connection speed? Will this be deployed on a gigabit network? Will you be using VLANS?

Also, I would avoid Realtek. Realtek NICs do not really offload the network stack.

WAN will be 10down 2up. Customer is paying for internet service and understands 64k per call. Gigabit everywhere. No VLAN. I can install another Intel PRO/1000 for only $30.

 

[Lifted]

I'd be a bit weary about setting up a PBX built with newegg parts. If the motherboard flakes out, how long can you be without this PBX? Generally telephones are the one thing an office cannot be without for long without have a serious negative impact on business. It's really the one place in the technology setup that you want something with a support contract in place for 4 hour repairs. Next day contract if you must be cheap about it.

TBH, with all the time and money invested into this, you can buy an off the shelf PBX for less than whatever box you can build. Probably won't have as many features, but it will be much more reliable. Once you factor in the 50 stations, the money you're saving by assembling a PBX will be < 10% or of the total cost of the voice infrastructure, that's not counting cost for SIP trunks and such. Over the next 3 - 5 years, you're looking at a few % in savings at most.

If it must be running Snom ONE, do yourself and your customer a favor and purchase an HP or Dell with a good next day or same day onsite service contract.

 

[pcunite]

I'd be a bit weary about setting up a PBX built with newegg parts. If the motherboard flakes out, how long can you be without this PBX?

I appreciate the sentiment, but it is easy to get these cheap mATX boards. We can buy three and keep them in storage. Excusing the "white box" factor, anything else stand out to you?

 

[Lifted]

I appreciate the sentiment, but it is easy to get these cheap mATX boards. We can buy three and keep them in storage. Excusing the "white box" factor, anything else stand out to you?

Nothing stands out with the hardware, but the bandwidth does. 50 calls at G.711 or G.722 and you're looking at 3.5 - 4mb. Once you realize that you're only getting 25 calls out of that 2mb circuit, assuming a perfect 2mb route to your SIP trunk provider, you haven't even factored in 50 people surfing the web. You might want to have a talk with your client regarding this 10/2 circuit he has or is ordering. Even with the best QOS out there, it's going to sound like they're calling from the inside of a steel drum on the dark side of the moon.

Edit: I assume you're using Snom phones since you've decided to use their PBX. The following opinion is based off 6 months of usage of a single Snom phone in my "lab" at home... it was the most expensive POS phone I have ever used. This was several years ago though, so maybe the quality of the phones and their support of them has gotten better over time. It was a Snom 360, which I see isn't available anymore.

 

[pcunite]

50 calls at G.711 or G.722 and you're looking at 3.5 - 4mb ... You might want to have a talk with your client regarding this 10/2 circuit he has or is ordering.

Edit: I assume you're using Snom phones since you've decided to use their PBX.

Yes, customer knows they can't do 50 calls on their service, but we want the hardware to be there if they go that route, they can always upgrade.

Yes, we will be using Snom 760's. I personally use a Snom 370 and Snom 300 and they've been solid for over three years.

 

[drebo]

That hardware has no chance of transcoding 50 g722 to g711 streams. Not a prayer.

Also, your audio quality will be terrible. Strongly suggest dedicated Internet for your SIP trunking or don't use SIP trunking.

You need to spend more than $500 in hardware.

Also, if you're going to spend $500 to build a Linux firewall, you may as well spend $500 on an SRX100 or an ASA5505.

This just screams of poor planning and bad implementation. I'm sorry for your customer.

 

[pcunite]

That hardware has no chance of transcoding 50 g722 to g711 streams. Not a prayer.

This just screams of poor planning and bad implementation. I'm sorry for your customer.

I'm here to enjoy the conversation and learn. I can sell, and I always take care of my customer. If something does not work out, I can always throw money at it. I like building boxes because of the extreme flexibility.

Every 1U PBX server on the internet claims to handle 50 calls on hardware much less than what I've spec'd here. Even Snom's own mini can do 20 and it is a low powered ARM box.

 

[drebo]

That's where you need to understand a little about how VoIP works.

If the PBX is not in the media path, it's very easy to handle lots of calls. That's how those smaller PBXs can claim as many simultaneous calls as they do. But the minute you start to add transcoding and media proxying, those numbers drop considerably.

There's a reason that most enterprise phone systems require dedicated hardware DSP farms and don't rely on software transcoding.

 

[pcunite]

That's where you need to understand a little about how VoIP works.

If the PBX is not in the media path, it's very easy to handle lots of calls. That's how those smaller PBXs can claim as many simultaneous calls as they do. But the minute you start to add transcoding and media proxying, those numbers drop considerably.

There's a reason that most enterprise phone systems require dedicated hardware DSP farms and don't rely on software transcoding.

Understood, can you point me in the right direction for building it ourselves? Sure, we can buy this or that, but I want more control for future projects. This is a stepping stone.

 

[pcunite]

From this link (see Step 4) it looks like my systems can handle 25 calls with software transcoding. I'll continue to research.

 

[pcunite]

But the minute you start to add transcoding and media proxying, those numbers drop considerably.

Thank you, this is helping. This link gives me some hard numbers. Hmm, need a $1000 box to do 50 calls. What are some hardware cards that can do the transcoding? If they are very expensive it might be cheaper to go with a $2,000 server, no? The new Intel Ivy chips don't use much power when not in use.

http://kiwi.pbxnsip.com/index.php/Hardware_Requirements