Asterisk and extensions across ADSL

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timwelch

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#15986 19-Sep-2007 08:37

Wondering if anyone can comment on this before I go too far down the track of trying this...

I've got myself an Asterisk box set up at home (Auckland) and was wondering of the feasibility of my parents down in the Waikato having a handset configured as an extension to this over their ADSL connection. This way when we wanted to talk we could just dial their extension and if they wanted to call 09 numbers they could just dial out using my PSTN connection.

Any thoughts? How difficult would it be to route through ADSL modem/routers?

Cheers, Tim

sbiddle

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#87118 19-Sep-2007 09:00

It's a very simple task.

It's no different to having a phone connected locally to your Asterisk box except you will have to ensure you have your Asterisk box set up to handle NAT correctly. You can simply configure an extension, take the phone to them, get them to plug it into their router (port forwarding may possibly required depending on the router) and you're away.

nate

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#87133 19-Sep-2007 10:10

We do this all the time with our Quadros (it's an IP PBX), and it is possible with Asterisk. It's commonly referred to as a remote extension.

Adding to what Steve's said above, you'll also need to have QoS (Quality of Service) otherwise the call quality will be very poor if you or your parents are browsing the internet at the same time.

tonyhughes

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#87140 19-Sep-2007 10:36

Have done this heaps without QoS on FS/128 lines, and on EVDO.
Works great (but without QoS could go yuk anytime)

Fraktul

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#87166 19-Sep-2007 14:07

As long as your not putting geographic numbers on the Asterisk box which reside outside the geographic area the box is in, ported TGA numbers for instance, its also kosher under the NAD.

timwelch

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#87188 19-Sep-2007 16:50

Excellent - thanks all for the replies. Sounds like it shouldn't be too difficult. Now just waiting for my TDM400P to turn up.

Speaking of QOS I've just read the manual of my Linksys WAG54G and I see that I can enable QOS for a specific port. I've worked out that port 5060 is for SIP routing but that this won't effect the call. Can someone tell me what the port(s) are for the actual voice traffic?

Cheers, Tim

timwelch

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#87306 20-Sep-2007 08:13

FYI (anyone reading this and trying to achieve the same)...

Here's a really good write-up of what I'm trying to achieve. Also quite a good tool for testing line quality for VOIP.

Cheers, Tim

sbiddle

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#87314 20-Sep-2007 08:56

timwelch: Excellent - thanks all for the replies. Sounds like it shouldn't be too difficult. Now just waiting for my TDM400P to turn up.

Speaking of QOS I've just read the manual of my Linksys WAG54G and I see that I can enable QOS for a specific port. I've worked out that port 5060 is for SIP routing but that this won't effect the call. Can someone tell me what the port(s) are for the actual voice traffic?

Cheers, Tim

The RTSP traffic ports are specified in rtp.conf in Asterisk. By default this is configured from 10000-20000 but in reality you can drop this down to a far more reasonable number like 100. Depending on the type of router and firmware you're using L7 filtering or using the MAC address for QoS can also be an option to look at rather than specific ports. I know the WAG54G doesn't do L7 using the Linksys firmware but from memory it does with a MAC address.

The ATA or phone you use may also have settings for the RTP which you can force to specific ports if you so desire.