atcomsystems.ca/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones Inconsistent IP phone operation

OK, I am pretty new to VoIP, as many of us here are. I have really only been working with it for the past year or so.

We have a Vodavi XTS in our office and we have a 768K Internet connection being delivered to us via a PRI. We were never successful in getting our router configured to allow VoIP, so we placed a five-port switch ahead of the router and connected our system's IP card there.

We have a remote office that has four IP phones that work off of our XTS. At that end, we have cable modem service and are using a Multitech Routefinder RPF560VPN.

The problem we are having is that the phones are incosistent and I am sure it has to do with QoS. Since we effectively don't have a router at the main office for our IP connection, we are simply using a static IP given to us by the ISP for the card. I am resonably sure that it's the router that handles the Qos, am I correct in this assumption? I am also assuming that certainly, if there's not a device that dictates packet prioritization, someone downloading a big file at the office end can be causing this.

We reach points where the phones need to be reset individually or the card in our system needs to be reset. Either way, it's a daily occurence and I am really having a difficult time explaining to sales reps. why their calls are being cut off or are garbled.

Anybody have a clue how I can solve this. Not really being good with IT issues isn't helping me here, so bear with my ignorance.



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Ed
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How come there's always enough time to go back and fix it a second time?

Ok, since your IP card is in front of the router, there's nothing to regulate the bandwidth you use. Thus if you download a big file from some website with a ton of bandwidth your internet connection will draw as fast as it can and all your ip phones will either lose connection or the voice quality will nosedive. With some routers you could leave your physical connections as they are and just restrict the download maximum on everything connected to the router to a number that leaves enough for the 4 ip phones left over. This seems inelegant to me. I'd figure out the port forwarding necessary to make the IP card work behind the firewall and then reserve bandwidth for internal IP associated with the IP card to push 4 remote phones. On the remote side, you'd need to do the same thing only reserve bandwidth for each phone/IP individually. In a true QOS setting you generally use a vlan and separate the VOIP from the regular data, but that requires far more expensive hardware than many places need. Also remember, even if you did all that I would do, you're still at the mercy of the internet as to packet loss, jitter, and latency. Unless you have a very unusual ISP on both ends, it's incredibly difficult to get them to enable true QOS routing. Umm, I think I've rambled on enough. Hope this at least gives you a direction to follow in asking more questions.

Your best solution:expensive:
a managed network WAN ,with layer 2/3 switches using VLAN's and prioritization for voice on the LAN no routers required.

Medium solution:medium expense/unmanaged network:
routers on both ends of the WAN, and layer 2/3 switches on the LAN
Prioritization of voice and data .these prioritized packets will relate to a TOS/difserv on the WAN.
This will put a packet header at the beginning of every packet.

problem: you must test your ISP to see if they are stripping off the packet header which is your voice prioritization.
there are programs that test this just by pinging the other end.

Work around: limit your bandwidth for data just like the other guy said.

What model router are you using? if it's cisco, you can cap the traffic for other apps using a QoS to prioritize the port used for VoIP

I almost fear writting here, due to my somewhat limited VoIP experience. With that being said. Three things glare 1) XTS IP phone only uses 24k band, 2) You need the router to not dynamically alocate bandwidth, 3)I don't like cable high speed ( have seen too much variance without explaination.

I always tell my customers to first make sure the things plugged in! LOL