VOIP call quality issues

[Green_Goblin]

Hi

 

I wonder if anyone could help with a problem I'm banging my head against the wall with at the moment?

 

We have FreePBX virtualized and going out to internet via Smoothwall on a 200Mbps leased line. Recently call quality has been intermittent with some calls experiencing missing audio. QoS is applied up to the router (Mikrotik RB2011).

 

FreePBX is in its own VLAN and connects to internet via firewall rules in Smoothwall. Phones are in the same VLAN and have QoS settings applied.

Before putting phones in same VLAN internal calls were affected but since placing them in the same VLAN as FreePBX they have been crystal clear.

 

I've applied bandwidth management and bandwidth limiting in Smoothwall but this has made little, if any, difference.

 

This was also happening a few months ago but seemed to be resolved. Speedtests showed we were only getting 100Mbps on a 200Mbps circuit and the problem went away when this was remedied, however, current speedtests show we are still receiving 200Mbps.

 

It may just be me but the issue doesn't seem to be strictly limited to heavy bandwidth usage, more how many PCs are being used at the time i.e. on Friday 5 IT suites were in use but, according to Smoothwall's traffic graphs we were only using around 20Mbps incoming and experiencing the issue, yet earlier on in the day we were hitting 150Mbps but the issue was barely noticeable.

 

Any ideas please?

[ibpalle]

Hi Green_Goblin

 

The bandwidth prioritisation on Smoothwall - can you see traffic being recognised and put in the right class on the monitoring tab in diagnostics? Just to confirm it's actually prioritising the traffic. Unfortunately Smoothwall can only prioritise traffic going through it, once it leaves and heads to the internet, it's out of it's hands

 

With the issue showing up even at low bandwidth usage, it does sound like a congestion issue along the path....

[bald_pig]

Hi

 

I wonder if anyone could help with a problem I'm banging my head against the wall with at the moment?

 

We have FreePBX virtualized and going out to internet via Smoothwall on a 200Mbps leased line. Recently call quality has been intermittent with some calls experiencing missing audio. QoS is applied up to the router (Mikrotik RB2011).

 

FreePBX is in its own VLAN and connects to internet via firewall rules in Smoothwall. Phones are in the same VLAN and have QoS settings applied.

Before putting phones in same VLAN internal calls were affected but since placing them in the same VLAN as FreePBX they have been crystal clear.

 

I've applied bandwidth management and bandwidth limiting in Smoothwall but this has made little, if any, difference.

 

This was also happening a few months ago but seemed to be resolved. Speedtests showed we were only getting 100Mbps on a 200Mbps circuit and the problem went away when this was remedied, however, current speedtests show we are still receiving 200Mbps.

 

It may just be me but the issue doesn't seem to be strictly limited to heavy bandwidth usage, more how many PCs are being used at the time i.e. on Friday 5 IT suites were in use but, according to Smoothwall's traffic graphs we were only using around 20Mbps incoming and experiencing the issue, yet earlier on in the day we were hitting 150Mbps but the issue was barely noticeable.

 

Any ideas please?

 

What was your internal network usage like? If you had 5 IT suites accessing a lot of files internally you could have a switch getting congested and dropping packets?

[Green_Goblin]

Hi ibpalle and bald_pig

 

It may just be me but the issue doesn't seem to be strictly limited to heavy bandwidth usage, more how many PCs are being used at the time i.e. on Friday 5 IT suites were in use but, according to Smoothwall's traffic graphs we were only using around 20Mbps incoming and experiencing the issue, yet earlier on in the day we were hitting 150Mbps but the issue was barely noticeable.

 

Sorry, this bit was badly written. I'll try and clarify; I've been testing calls myself and at the point where it breaks up I can be looking at the traffic graph and it may be showing 20Mbps but a second or so after jump up so I guess what I'm wondering is if there is a delay on the info on the traffic graphs or is it really only using 20Mbps at the point of the issue? Similarly there can be high traffic before the issue is noticed but the traffic graph can have dropped down by then.

 

Hi Green_Goblin

 

The bandwidth prioritisation on Smoothwall - can you see traffic being recognised and put in the right class on the monitoring tab in diagnostics? Just to confirm it's actually prioritising the traffic. Unfortunately Smoothwall can only prioritise traffic going through it, once it leaves and heads to the internet, it's out of it's hands

 

With the issue showing up even at low bandwidth usage, it does sound like a congestion issue along the path....

 

Yes, I can see the traffic being put in the right class.

 

What was your internal network usage like? If you had 5 IT suites accessing a lot of files internally you could have a switch getting congested and dropping packets?

 

To be honest, as we've had no complaints of internal call issues and noticed none ourselves I wasn't looking at local switching. We don't have anything installed to test internal network usage since The Dude started crashing my PC. Any suggestions please? We use HP switches.

[ibpalle]

Hi again

 

The realtime display does have some delay - it's a web interface after all. Iy you would like to see a more precise listing, try on the command line using the command 'iftop'

 

iftop -i ethA will show traffic on the designated interface. You can see interface names using the 'ip addr' command.

[Green_Goblin]

Hi again

 

The realtime display does have some delay - it's a web interface after all. Iy you would like to see a more precise listing, try on the command line using the command 'iftop'

 

iftop -i ethA will show traffic on the designated interface. You can see interface names using the 'ip addr' command.

 

Excellent, thank you. I thought that might be the case with the web interface. I'll continue to test and monitor.

 

Other than adding a proxy exception for the VOIP server, bandwidth limiting and bandwidth shaping is there anything else I can do Smoothwall side?

[ibpalle]

Proxy exception for the VoIP server is a good idea but I doubt it will have any effect on VoIP traffic since that only applies to HTTP(S).

 

I'd probably try to setup a rule in bandwidth management to restrict web traffic overall to 90% if the total capacity, leaving 10% wiggle room for other types of traffic when user web browsing is at peak. Percentages can of course be adjusted to suit context.

 

Thats in addition to a high priority rule for the VoIP server. Is VoIP traffic only coming and going to the server - clients are not communicating directly?

[Green_Goblin]

Thats in addition to a high priority rule for the VoIP server.

 

Where would I apply a high priority rule for the VoIP server please?

 

Is VoIP traffic only coming and going to the server - clients are not communicating directly?

 

Not sure I understand the question. Do you mean do internal calls connect directly client-to-client rather than via the VoIP server?

Edited September 23, 2019 by Green_Goblin
Edited for clarity