Mitel 5000 system, Mitel 5330 IP Phone and VPN tunneling

[Rob F-attotech]

Greetings all.  We have recently installed a Mitel 5000 used along side our aging Inter-tel Axxess system.  We deployed two IP phones to remote users.  So far, one user has reported static and garbled voice quality.  The tech that installed the system suggested the poor QOS is due to the unsecured cloud connection and recommended we look into VPN tunneling to resolve this issue.  When I asked about what VPN appliance they would choose, they had no recommendation.  Is this the path we should be following?  Has anyone here done this successfully?  Many thanks!!!

[NTEDave]

I'm not convinced a VPN will make any difference, if you have one user that works ok and another doesn't it's most likely to be the other users broadband connection, router or similar.

Have you got the user who is experiencing issues to run speed tests on their connection, do they have issues with general internet access?

In answer to your question we have lots of remote phones dotted around using NAT and port forwarding on routers, we also have a chain of shops using Draytek Routers providing VPN connections back to the head office where the 5000 is.

[bhackbarth]

First of all the public internet is "best effort" at best when it comes to 'QoS'.  Some providers will provide better than "best effort" for RTP and SIP packets. But, there's no guarantee the next hop (router down the line will do that, so everything should be considered "best effort" in other words pray the packets get there timely, if at all.  Concealing those packets in a VPN will guarantee you that you will always be stuck at best effort though because the ISP can't see them and prioritize them. Second, security has nothing to do with it as Mitel doesn't send RTP in the clear, so you can't just load software and listen to conversations in progress.

Prioritizing where you can, i.e., the local switch and router, can help with traffic that is competing at your local site. For example, if a couple users start downloading files and saturating the link. Once it leaves your site you're at the mercy of the ISP and that can be a difficult place to be.  A cheap home router in it's default config will send everything best effort, so if you start enough downloads and make calls with the teleworker phone, the garble will start.

[acejavelin]

I am with NTEDave and bhackbarth on this one, if you have a bad link in/out of the cloud, it's a bad link and no amount of hardware or software is going to fix it. In fact, I would bet money that if you install a VPN you will make the problem worse, since a VPN tunnel adds overhead to the connection.

I really doubt any configuration on your end or the far would make any difference if the connection is poor, QoS is lost in the cloud anyway, basically you have QoS everywhere or no where, there is no "QoS here, not here, and then here again".

Best bet... change ISPs to get one that provides better service, or get the existing ISP to "fix" the existing connection, although it might be broken, it might just be the way it is.

[nintendo1889]

First of all the public internet is "best effort" at best when it comes to 'QoS'.  Some providers will provide better than "best effort" for RTP and SIP packets. But, there's no guarantee the next hop (router down the line will do that, so everything should be considered "best effort" in other words pray the packets get there timely, if at all.  Concealing those packets in a VPN will guarantee you that you will always be stuck at best effort though because the ISP can't see them and prioritize them. Second, security has nothing to do with it as Mitel doesn't send RTP in the clear, so you can't just load software and listen to conversations in progress.

Prioritizing where you can, i.e., the local switch and router, can help with traffic that is competing at your local site. For example, if a couple users start downloading files and saturating the link. Once it leaves your site you're at the mercy of the ISP and that can be a difficult place to be.  A cheap home router in it's default config will send everything best effort, so if you start enough downloads and make calls with the teleworker phone, the garble will start.

Excellently-worded response. I saved it in my email templates.

I remember reading a wikipedia article that mentioned the reasoning behind the lack of qos on dsl/cable/residential connections (all I remember is it mentioned dark fiber, the market downturn of 2001, and after 2001 providers stopped prioritizing different types of connections, whereas previously bandwidth was carefully prioritized, and now bandwidth is an all-you-can-eat smorgashbord [btw, you can't just keep throwing bandwidth at a qos problem afaik. It can help, but not solve it]). If anyone knows the article I'm thinking of, please let me know.