Reaching a SIP Trunk on the other side of the Bridge

[carlosmarchi]

Hi Everyone!

I'm reading a little bit more about bridges, and surely I can put them to test, but before that I would like to discuss what I'm trying to achieve to be sure that this is the best way to do it.

I'm affiliated to a voip provider from where I'll be buying numbers and assign them to my end-users. The inbound part is easy, they allow me to associate numbers with IP Based SIP Trunks and then they direct the call to the assigned IP. But the outbound is a little trickier, because I only have one account that must place calls from a single IP. So, I tought about having an instance of my own where this outbound SIP Trunk would be set, and then my customers instances would be bridged to this one so they can route the outbound calls through it.

Does it make sense or is there a simple solution?

Thank you,

 

[cobaltit]

Technically it's possible but not recommended. You should stop trying to game the system and do it the right way. All you are doing is building in a single point of failure for your customers. You're also going to need to keep upping your license to deal with the simultaneous calls. Just not a good idea all around

 

[carlosmarchi]

I totally agree that it doesn't sound like a very good strategy, but as awkward as it can be, it was their suggestion to do it this way, I'm not trying to game them. This IP source limitation also only came to my knowledge after I was onboarded and the first batch of numbers have been ported. And it doesn't make too much sense, since on the other side I can receive calls to different IPs (or this could reinforce their suggestion that this is the way they use to work).

I had already considered the question about upping the license, their service is so cheapier than the others that even this cost could be easily absorbed.

I'll probably leave this account as is to attend just an instance that is already running and go for another solution.

Thank you for sharing your experience.

 

[rc179]

SBC it's what they do.

 

[carlosmarchi]

I thought about using SBC, but I came back to where I started, having trouble to place the calls with the wholesale provider. I've insisted with them about this strange behavior but this is really the way to go, only one IP for outbound. They suggested using a lean asterisk/freeswitch (disabling most of the modules and leaving only the essentials) with just one trunk to receive the calls from different IPs (my customers PBXs) and "bypass" the calls using the authorized IP.

That's what I ended up doing and it's working fine.

It will still add a small cost (I'm running these on AWS) and it's always another point of failure as cobaltit pointed, but I think it will be reliable enough. My first customer and most of my prospects for now are more focused on receiving calls, so I don't think this is going to be a problem.

I'm in Brazil, somethings here have no reasonable explanation.

 

[rc179]

It may just be a something about the 3CX SBC, but it sounds like you're trying to be a small CLEC or the Brazil equivalent. Trying to use a PBX for this isn't a good long term idea. A small true SBC like the Sansay would do it much better. They've got a pretty nice HA pair setup too.

But you might want to talk with 3CX first, maybe they have a pure SBC solution, aggregating multiple systems through a single connection/location is what an SBC does, I can't understand how anything called an SBC wouldn't be able to handle it. Maybe it's because it's running as both an SBC and a PBX.

 

[carlosmarchi]

I've had to google CLEC , in Brazil they are called 'mirror companies', don't know exactly why. It would be a much broader telecom operation, what I'm looking for is just to pack a VoIP service with my 3CX sale (buying DID's and termination in bulk to resale). And when say 'bulk', in Brazil this is starting with just 20 DIDs, so it's a small operation. I'm not looking to achieve more than a 100 DIDs in a short or even medium term, that's why I think it's really manageable to live with this freepbx gateway on outbound calls.

I didn't know the product that you mentioned, the Sansay SBC's (or any other SBC except the 3CX), but I think it would also be overkill for what I'm setting up. I'll read more about it later.

For now I only needed an outbound gateway to route outbound calls from multiple 3CX instances, through a single static IP, since I can receive calls from the provider straight to multiple IPs (linking DID's to SIP-Trunks at their platform) but I need to place the outbound calls from a single IP.



My business is an IT outsourcing for small companies, at this moment this solution is complimenting my portfolio (but I confess that I'm excited about the capabilites of the actual 3CX, I think it will end up playing an important part in my business and I'll work for that).

 

[rc179]

I would expect that the 3CX can be provisioned to provide inbound trunks to other systems and then rout the calls out it's outbound trunk, certainly other systems can do this and 3CX does have SBC capabilities.
Keep in mind that you are adding hops to the audio path, this adds latency and jitter, which means reduced quality. Also pay close attention to the codec used by the carriers, you do not want to be transcoding anywhere.
Until you get to a higher volume and can do a small SBC (Sansay has small units, it's not like Acme Packet), you may want to consider a carrier that allows you to be a reseller of their services, that way you get a small piece of the action without the complication, equipment, and maintenance of rolling your own.