2U Linux PBX and firewall servers

[pcunite]

I need to build two 2U rack mount Linux boxes. One will have Snom ONE PBX 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. Gigabit everywhere.

 

I would appreciate your opinion on the hardware I've chosen. Is the CPU powerful enough? Overkill is fine.

 

Hardware $500 budget per box:

• 
   
  
• Case - iStarUSA $80
  
• MB - ASRock H77M $80
  
• CPU - Intel G2020 $70
  
• RAM - Crucial 4GB $50
  
• PSU - Corsair CX430 $50
  
• SSD - Crucial M4 64GB $70
  
• NIC - Intel PRO/1000 $30
  

[Vodia PBX]

The specs look okay with me. Should be definitively good for 50 calls.

[pcunite]

The specs look okay with me. Should be definitively good for 50 calls.

 

Thank you. Looking at this link does agree, however, unless I do certain types of Transcoding. Is there a way to avoid those situations? When calls stay inside the PBX (user to user) I like to have G.722, for the outside world it is fine for the PBX to choose whatever codec it thinks it needs. Most calls will come into the PBX from people on PSTN devices.

[Vodia PBX]

G.722 can give you better quality only if both sides are using G.722. If one side uses G.722 and the other G.711, then the resulting quality will be worse than G.711. Transcoding can make the call never make sound better.

 

Transcoding between the trivial codecs such as G.711, G.726, G.722 is not very CPU intense. Even if you have to transcode 50 calls between those codecs, the CPU will be still able to handle this. Only when you are getting into GSM, G.729A or even things like speex, iLBC or OPUS transcoding then the CPU might get under heavy load.

 

The PBX tries to avoid transcoding. IMHO today it is still a very reasonable choice to just leave everything on G.711; especially if bandwidth is not an issue and most (important) calls terminate in the PSTN anyway.