VOIP and DSL

[mattmc97]

I have my office phones connected to the PlugPBX and also directly to VOIP.ms in case the plug goes down.

Our office phones (Linksys SPA942) and PlugPBX seem to lose registration on a semi regular basis. The phone will have a yellow light on the line and show the registration failed while the PlugPBX will show the trunk as not registered.

Is this due to not having a static DSL address or would a static address help any?

What is the best way to determine what is causing the failures?

This is getting frustrating!   

mattmc

[BinaryTB]

Is the office behind a NAT? Also, setup some sort of cron job where you ping some server every 30 seconds or so and log the result, at least you'll be able to tell if it's an external DSL issue or not. And doesn't hurt to check any other logs, who knows, maybe there's a torrent running somewhere in the office (or some sort of trojan) that's overwhelming a switch/router, making it reboot/crash thus losing the UDP state that SIP needs. One more thing, if your voip provider allows TCP registrations, try that too.

[PlugPBX Admin]

Does it happen when the IP changes? Grep thy logs

You should do what I do. EVERYTHING in my home dumps to a little NAS that has syslogd, my router, my wireless AP's, the ATA, PlugPBX, and other devices. THEY ALL dump to a single syslog server. Then I can just grep out patterns and correlate whats occuring. No muss, no fuss.

Bonus points. I have Grep scripts that fire each day and send me summary of PPPoE down events, so I can track how stable my setup is.

The point is....Fixed IP is ALWAYS better. Depending on what you use as a router, it may trash its NAT mapping tables on a PPP down/up event. DD-WRT did this to me lots. Depends what your UDP or TCP timeouts are.... SIP verses IAX, and so on and so forth.

Sure fire solutions?

1) Get a fixed IP
2) Run a decent router (either something professional) or.... I suggest...

Tomato.

www.tomatousb.org  - find a router that runs this and just use it. Fixed IP address is also king. If you are running a business phone system off DSL connection who's lease # changes, you are in for a world of hurt no matter what. Get a fixed IP from your provider, get a stable router and you'll have a rock solid connection again.

[mattmc97]

I ordered a static IP. Everyone is tired of losing phone registrations, so hopefully that fixes it.

I have a Draytek Vigor 2920 which has dual WAN setup, VOIP QOS and was highly rated by one of the VOIP websites I was looking on.

I am actually running Tomato USB on a Asus RT N-10 at home with a SPA 2102 behind the router. I am, actually was, trying to dump my POTS line and use callcentric, but callers keep getting the Callcentric error when the SPA loses it's registration about 3 times per day. Totally shot the WAF (wife acceptance factor) to zero.

I don't know if the Asus router is junk or what, but it will periodically kick my laptop off the network as well & the only way to get wireless back is to reboot the router. I have set the router to reboot every night at 2 am and that seems to help the wireless not kick me off in the last week. I only use it at night though as it is my traveling work laptop.

So it is back to POTS until I can find a decent QOS solution.


Anyone use an ALIX board with m0n0wall or pfsense?  That is what I am thinking of trying next.

[BinaryTB]

Strange, I'm using an E3000 with Tomato USB, no problems whatsoever. Actually, I remember that I did have to disable the SIP Nat Helper in Tomato USB settings, it was screwing up Asterisk's sip/nat/externip stuff. Been running for a few months, no problems at all, no registrations lost, no reboots necessary.

For my dynamic ip, I've got asterisk to check its external ip every 5 minutes, don't know if that matters. Well now that you have a static ip, I guess it wouldn't.

[mattmc97]

I got my static IP at work today and I have not lost a single registration on the phones all day! So hopefully that is solved.


As for my Home DSL with Tomato....

BinaryTB's post got me revisiting the Tomato USB issue and searching on SIP Nat Helper led me to a discussion on tomato and how the UDP timeouts were making people's ATA mess up.

So I thought I would ask you to guys to dbl check my tomato config and see if everything looks good now.

[PlugPBX Admin]

Well look at your TCP timeout. 1200 seconds.

SO if your SIP registrations to your VOIP provider are TCP, yer fine.

BUT if you are using SIP over UDP (or IAX) then and you only re-register say every 2 minutes, your router can be closing the ports prior to the registration re-firing, and that would be bad.

So IF any voip traffic is over UDP, you'd want to turn those up to be slightly larger then the re-registration period.

So I was right about static IP's  *wink*

Its the number one thing to make any VOIP setup work MUCH better.

[mattmc97]

Tcp timeout is set based on the liksys forum tomato qos guide.

Registration is over UDP with callcentric.

It appears on the SPA-2102 'Info' page, it is re-registering every minute.  I have not found where to set this though.

My Nat Keep Alive Intvl is set to 30 which is what the linksys forums tomato guide had it set at.

My register max expires is set to 600.

so where do I find my re-registration intvl?

also, it is consistently re-registering every minute, is that a problem?

[BinaryTB]

I kept my Conntrack settings at the default (except for max connections, that's 4096) and things work fine. So my UDP timeouts are Unreplied 30 and Assured 180.

Also, in QoS, setting the max inbound limit to 0 (or 10, which is the lowest in the latest versions I believe), is the same as not setting an inbound limit. Got mine at 10 kbits and my download speeds max out. Don't know if setting it to 999999 helps/hurts QoS at all though.

I also don't prioritize small packets in QoS. If you max out your download speed and then get a SIP phonecall, I've noticed audio issues (sounds cuts out, etc) in my setup, even when my SIP was set to highest.

Sounds like I got lucky by having things work great without having a Static IP. But then again, I'm using dynamic dns. Got Tomato to update my domain (through dynamic dns) if my ISP ever changes my ip address. Then in Asterisk, I've got it set to check my domain every 5 minutes to get my external address and of course I've got all the nat stuff enabled and port forwarding and all that. Things work smoothly (once I disabled the tomato sip nat helper, as mattmc97 mentioned).

[mattmc97]

Ok. Stupid question warning.

I have 5 AT&T DSL static ip addresses for work and I don't need them all. Is there anyway to use one of those on my AT&T DSL connection at home?

I would guess not, but i figured I would ask.

Udp unreplied should be less than Nat Keep Alive on the spa 2102, I don't think that assured matters too much, according to the forums.

on tomato, inbound has to be between 10-999999

[twinclouds]

Will DDNS server + dynamic IP work in this case?  Of course the VOIP service provider need to take the assigned hostname instead of the actual ip address.