Technical Discussion
  >> Voice over IP (VoIP) Forum


Register (or login) on our website and you will not see this ad.


Pages in this thread: 1 | 2 | 3 | (show all)   Print Thread
Standard User TimJ
(committed) Wed 24-Mar-21 11:37:38
Print Post

VOIP and CGNAT compatibility (Airband FTTP)


[link to this post]
 
We have VOIP service with Port5060, through Airband FTTP, an openWRT router, a Cisco SPA122 ATA and Panasonic DECT base and phones.

Sometimes (say 1 in 5-10 calls) when the phone rings it correctly displays the callerID, we pick it up and there is nobody there. Hanging up and trying to ring back, there is no dial tone. Talking to the caller, the remote end just keeps ringing. I think we get a dial tone back when they give up ringing.

Port5060 are blaming Airband's CGNAT and say that there is no workaround.

I will raise a ticket with Airband, but I hold out zero hope of them actually doing anything.

Are there any workarounds or are we stuck with a copper line for eve? (Well until they disappear.

Thanks for any suggestions.
Standard User Pheasant
(experienced) Thu 25-Mar-21 09:21:35
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
Sounds like either a SIP re-registration issue and possibly the one way audio is down to RTP stream being blocked or port timeouts somewhere in the food chain between your ATA and the provider.

On your side you may need to look into the SIP settings on the ATA to alter the SIP registration interval. Check any NAT traversal settings are enabled. You may possibly look at your firewall settings. I’m not au fait with your router but it may be worth tweaking SIP ALG setting to see if it makes any difference (better or worse!)

Some of these links may help in your understanding of what is going on and where the issues may lie:

https://phil.lavin.me.uk/2020/08/a-tale-of-voip-nat-...

Unfortunately a lot of the time it is something in the carrier network that kills stuff not always necessarily CGNAT. On my setups over the years I had decent performance with some wireless providers, namely Vodafone and EE (either on 4G or 5 connections which are all CGNAT). However I had no end of issues with Relish (now part of Three) and could never get decent VoIP service running over their net.

If you are reasonably techical you could packet sniff the network using wireshark to see what is happening with the UDP traffic related to your service.

My Broadband Speed Test
Standard User danielhyde
(member) Thu 25-Mar-21 09:29:01
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
I'd say its your VOIP providers issue as I have used VOIP behind CGNAT and have customers that do so with no issue.

Thanks
Dan


Register (or login) on our website and you will not see this ad.

Standard User Pheasant
(experienced) Thu 25-Mar-21 13:47:48
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: danielhyde] [link to this post]
 
Easy way to test that is for the OP to open a free basic Sipgate account and enter the credentials on the ATA to test with.

In my experience it’s been the opposite. It’s usually the network rather than the VoIP provider that’s the issue.

My Broadband Speed Test
Standard User nemeth782
(committed) Thu 25-Mar-21 19:06:22
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
SIP doesn't tend to like NAT very much in general although obviously there are workarounds.

Does Airband support IPv6? This may be the other solution, as everything should work with no NAT there.
Standard User Michael_Chare
(fountain of knowledge) Fri 26-Mar-21 12:25:23
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
I have a Cisco SPA 112 with the latest firmware which I recently updated. For my main service I have the "Register expires" set to 60 seconds, instead of the default of 3600 secs. There is also a "Auto Register When Failover:" not mentioned in the manual which I have now set to yes.

There is a Cisco forum for their ATAs.

Michael Chare
Standard User tarka_the_otter
(newbie) Fri 26-Mar-21 13:13:04
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
Tim - I am also with Airband (but just their Wireless stuff) - and had awful problems with getting router to router VPN links working with their NAT because it was randmonly alternating between two different IP addresses while the connection was still active - even doing a keep alive ping did not stop this it would happily start with one external IP address and then at some point just flip to the other and later flip back etc.

I can't help but think this is a config issues somewhere in the Airband stuff but it plays havoc with anything that needs to connct back - in my case whenever the IP changed my VPN dropped and as remote end was using Dynamic DNS address to allow it would not then let me reconnect until the other end (which I did not control) refreshed or timed out it's DNS cache and looked up the actually IP again.

On the back of persistent moaning Airband gave me a static address. It might be worth checking if your address is also dong this - I setup a powerShell loop sending:

(Invoke-WebRequest -UseBasicParsing ifconfig.me/ip).Content.Trim()

to get my address
Standard User Pheasant
(experienced) Fri 26-Mar-21 21:49:14
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: tarka_the_otter] [link to this post]
 
Change network provider (they sound utterly rubbish. Life’s too short). Keep the VoIP provider.

My Broadband Speed Test
Standard User TimJ
(committed) Sat 27-Mar-21 00:16:17
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: Pheasant] [link to this post]
 
Thanks you for all your replies, Very useful.

The current situation is that searching the openWRT forum I found a post about similar symptoms and their fix was to install nf-natfiler-extra kernel modules, I have now done this, it remins to be seen if it has fixed the problem.

Port5060 have come back saying that VOIP "should" work through the double NAT of my router and CGNAT, but it is not guaranteed. They have suggested as a test connecting the SPA122 directly to Airband PPoE feed, this would show if the problem is my router or CGNAT.

Thanks for the links , I may well resort to studying and understanding the protocol and using tcpdump on the router.
Standard User TimJ
(committed) Sat 27-Mar-21 00:29:04
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: Pheasant] [link to this post]
 
If only there was a choice.

Unfortunately Faster Worcestershire awarded the contrct to install FTTP here to Airband so they have a monopoly.

Adsl is around 2Mbps, in the house there is almost no mobile signal, but up at roof aerial height O can get a Three signal around 20Mbps, I lived with that for 18months and that is still an option.

My FTTP connection was paid for by a Gigabit voucher, so I am committed to Airband for 12 months.

I suspect that their business plan is to make their profit from the grants and vouchers for intalling FTTP, they are not interested in running as an ISP.

Another issue I have with them is that although speed tests come in around 200Mbps and pings to 8.8.8.8 in the 7-8mS I get frequent iPlayer issues, buffering, "something has gone wrong" or just being kicked out of iplayer back to live TV.
Standard User TimJ
(committed) Sat 27-Mar-21 00:35:29
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: tarka_the_otter] [link to this post]
 
Interesting, one evening I was logged to a VPS via ssh and I noticed that my IP there was different to that given by speedtest.net.

You managed to avoid their exorbitant £10 per month charge for a static IP.

They certainly push the aspect of using VOIP on their website so it should work.

Tim
Standard User Pheasant
(experienced) Sat 27-Mar-21 05:16:47
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
It’s worth also directly testing with a soft phone client on a laptop or pc. This eliminates any added complication with the ATA as it’s straight VoIP endpoint to provider. In fact leave the ATA disconnected if testing to the same VoIP provider in this way.

Using a laptop / PC soft client means you can check
1) connection behind the WRT. This takes the ATA out of the loop
2) direct laptop wired network connection to the ONT by setting the pppoe client connection on the laptop. This takes the WRT out of the loop

Soft phone client testing means you can more easily flip between port5060 and another VoIP provider for further testing.

My Broadband Speed Test
Standard User Pheasant
(experienced) Mon 29-Mar-21 11:43:36
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
In reply to a post by TimJ:
Thanks you for all your replies, Very useful.

The current situation is that searching the openWRT forum I found a post about similar symptoms and their fix was to install nf-natfiler-extra kernel modules, I have now done this, it remins to be seen if it has fixed the problem.

Port5060 have come back saying that VOIP "should" work through the double NAT of my router and CGNAT, but it is not guaranteed. They have suggested as a test connecting the SPA122 directly to Airband PPoE feed, this would show if the problem is my router or CGNAT.

Thanks for the links , I may well resort to studying and understanding the protocol and using tcpdump on the router.

As said try also with a soft phone connected (and with another VOIP service on a trial basis). This way you can connect directly from the Airband ONT port removing your router and ATA from the equation to simplify fault finding

My Broadband Speed Test
Standard User TimJ
(committed) Mon 29-Mar-21 19:18:30
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: Pheasant] [link to this post]
 
As said try also with a soft phone connected (and with another VOIP service on a trial basis). This way you can connect directly from the Airband ONT port removing your router and ATA from the equation to simplify fault finding


Thank you for your suggestions, they are appreciated.

The problem is very intermittent so to be meaningful any test has to be for weeks, and thus has to be compatible with maintaining both incoming landline and full house Wi-Fi.

The initial VOIP setup was using Airband supplied router, this quickly showed the incoming call problem and after a few days we went back to just the landline. I then setup the openWRT router and went back to VOIP. We had about 10 days error free use, but then 3 days with around 50% unconnected calls. ( we get around 3-4 calls per day). Since installing the Nathelper-extra package we have had 3 days of error free service. We also have had 3 evening of buffering free iPlayer/Netflix. After 3 days is this significant?.

If the problem is not fixed I plan as a temporary test I plan to try using the SPA122 as the router. This would eliminate my router.

The Airband fibre comes through the wall and terminated in one of These, I assume this is the same as an ONT, then a cat5e to the router. Would it work if I put a gigabit switch in this line and connected both the router and the SPA122 or slaptop with softphone? I wonder if Airband supports multiple sessions?

I am also concerned about oddities around the public IP. Tarka-the-otter reports IP address changing with time, In late Dec I definitely saw that the external IP when logged into a VPS using ssh showed as 1 different to that shown by speedtest.net.

The last 3 days I have had a script running checking the public IP using both ssh (port 22) and https (port 443), both have remained the same and constant.
Standard User Pheasant
(experienced) Mon 29-Mar-21 21:58:48
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
That sounds quite positive with the Nathelper-extra patch applied. Three days error free is good, but if there are likely periodic NAT address updates in the carrier network, you may not see the change (and hence suffer a potential VoIP issue) unless testing over a longer term. I would want least a week or longer to deem it reliable and if you can push more calls through, even test calls inbound from your own mobiles to push the service.

The Genexis device you linked to is indeed an ONT (aka ONU). It will require a router (or PC) directly connected to its ethernet port to establish a PPPoE authenticated session back to the Airband access concentrator. You can't just connect a switch directly from the ONT (unless that switch is routing/Layer 3 capable but I digress) and then router and SPA etc hanging off the switch.

Either you need an actual router, a PC or another device (like your SPA) that is able to run a PPPoE client first in line. This is effectively your gateway. Then either the same (or separate device) to route/share/distribute the service from the LAN side to all the other devices inside your network. Hope that makes sense.

I don't know too much about how Airband backhaul their network - there are old press articles floating about which suggest they use a mixture a wireless towers - so its certainly not fibre all the way back. There may be more to these intermittent issues than just CGNAT.

My Broadband Speed Test

Edited by Pheasant (Mon 29-Mar-21 22:06:28)

Standard User TimJ
(committed) Tue 30-Mar-21 17:02:44
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: Pheasant] [link to this post]
 
Thanks for your comprehensive reply.

It has now been 4 days and counting, so I am hopeful, but time will tell.

During the initial meetings Airband said that their "cabinet" would be located at the local pub and there would be a Microwave backhaul. This was to speed up installation,but their plan was eventually to move to a Fibre backhaul.

however they installed their "cabinet" immediately adjacent to an openreach FTTC cabinet, and the installation engineer told me we were one of the very few area that had entirely a fibre backhaul.

A traceroute looks like this.
[email protected]:~$ traceroute 9.9.9.9
traceroute to 9.9.9.9 (9.9.9.9), 30 hops max, 60 byte packets
1 OpenWrt.lan (192.168.1.1) 2.478 ms 2.613 ms 2.850 ms
2 10.247.254.1 (10.247.254.1) 9.715 ms 10.939 ms 10.184 ms
3 10.255.255.153 (10.255.255.153) 13.569 ms 14.015 ms 14.009 ms
4 asr1.lr1.thn.air-band.net (185.130.156.78) 13.238 ms 13.511 ms 13.494 ms
5 195.66.225.238 (195.66.225.238) 32.174 ms 32.482 ms 32.959 ms
6 dns9.quad9.net (9.9.9.9) 14.197 ms !X 7.860 ms !X 9.646 ms !X
Standard User Pheasant
(experienced) Tue 30-Mar-21 21:45:26
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP)


[re: TimJ] [link to this post]
 
No worries. 🤞that kernel patch on the WRT has done the job.

Trace route looks absolutely fine. Just an extra hop than what I’m seeing on my setups. Looks like you did the test over WiFi, not that it matters. Looks good.

My Broadband Speed Test
Standard User TimJ
(committed) Thu 01-Apr-21 08:35:17
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: Pheasant] [link to this post]
 
Well after 4 good days we had another incoming call fail. Usually things correct themselves, but this time it left no dialing tone and incoming calls getting number unavailable. The lights on the SPA122 appeared to show that it was stuch in aloop rebooting. The router log showed that theethernet going to it was continuously going up/down. A power cycle sorted it out.

My monitoring of the public IP and traceroutes did not show any signs of change.
I raised a ticket with Airband, but except for an automated reply nothing, so as expected.

I think my options are, (sorry just thinking out loud)

1) Give up with VOIP and just keep the copper landline, and put up with the cost of £12.60 per month
2) Do we really need to maintain a landline number? It used to be essential due to poor mobile coverage, but we have both recently updated mobiles, and now have reliable WiFi calling.
3) Airband advertise VOIP as an advantage so ask them who they recommend and how to set it up.
4) Tell Airband that we cannot get VOIP to work reliably, VOIP supplier suggest changing to static IP, try to avoid being charged for it. This would also have other advantages.
5) As a test connect the SPA122 directly to the Airband feed and also use it as the house router. This would either clear or implicate the router, but i am now sure what the next stage would be.
6) Try replacing the SPA122 with a softphone on one or both mobiles. If this worked it might be a permanent solution.

Other thoughts I have had are are to run Asterisk on the router or to to create a VPN between the SPA122 and my VPS thus bypassing Airband. But I am not sure that I am technically up to either and that they would probably just complicate the issue and make things worse.

I think that I am leaning toward 4 and or 6.

Thoughts welcome.
Standard User Pheasant
(experienced) Thu 01-Apr-21 09:06:07
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: TimJ] [link to this post]
 
In reply to a post by TimJ:
The lights on the SPA122 appeared to show that it was stuch in aloop rebooting. The router log showed that theethernet going to it was continuously going up/down. A power cycle sorted it out.

To me that suggests you have internal network issues going on - the SPA itself with the reboot loop. Also the flapping Ethernet port on the router needs checking. Neither of those sounds good.

My Broadband Speed Test
Standard User TimJ
(committed) Thu 01-Apr-21 09:32:26
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: Pheasant] [link to this post]
 
The flipping port on the router was due to the SPA reboot loop. But I agree it does suggest a problem with the SPA, but this was immediately after the failed call, so which is cause and which is effect?

Points to using the softphone in place of the SPA, it is also very easy to do.
Standard User Pheasant
(experienced) Thu 01-Apr-21 12:22:35
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: TimJ] [link to this post]
 
Yeah the SPA should come out and test with another device. Even if the SIP registration is at fault it should not cause the SPA to go into a reboot loop. That is not right at all.

SPA's have a bit of a reputation for being a bit flaky. The last generation I used was the old SPA3102 which is going back some years now. I still have the original (and a fresh spare in a box) which was routing PSTN into Asterisk (FXO) and taking then acting as an SIP extension ATA onto a cordless base (FXS).

Since then the landline disappeared, pure SIP trunks, went over to DECT on the domestic phones and used a couple of N300A IP Gigaset's across properties but talking back to an Asterisk box. This trusty old thing has been running solid since 2012 and the version of Asterisk (12) and Centos (6) have both been EOL and are long overdue an upgrade. But it has worked faultlessly over VM cable, 4G, 5G, FTTP, leased line you name it its done it.

My Broadband Speed Test

Edited by Pheasant (Thu 01-Apr-21 12:23:48)

Standard User TimJ
(committed) Fri 02-Apr-21 10:19:09
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: Pheasant] [link to this post]
 
I fully agree going into a reboot cycle is screaming of a hardware problem.

This is embarrassing. A close examination of the SPA showed that the power adaptor is rated at 5V 1A, but the SPA122 spec says power requirement 5V up to a maximum of 2A. It clearly is not the original power adaptor.

Now replaced with a 5V 3A supply, we will try again.....

I am extremely annoyed with myself for getting into this situation and wasting many hours. Thanks all for yout suggestions and help.
Standard User Pheasant
(experienced) Sun 04-Apr-21 07:28:19
Print Post

Re: VOIP and CGNAT compatibility (Airband FTTP) What Next


[re: TimJ] [link to this post]
 
Keep monitoring the ATA after the power supply replacement. That could be a red herring.

It may at be worth looking through the device logs, especially around the time the device has issues. If there are network or registration issues, then this may provide some clues or basis for investigating further.

There some good Cisco expertise on their community forums too. May be worth posting the problem there. As an example:

https://community.cisco.com/t5/atas-gateways-and-acc...

My Broadband Speed Test
Pages in this thread: 1 | 2 | 3 | (show all)   Print Thread

Jump to