atcomsystems.ca/forum Forums General General Telephone & Systems Information Am I making a mistake... VOIP???

I just received some fine advice over on the cabling section of the forum, thanks. I was directed here to continue my investigations. Here is what I am about. I have a new installation, am an "IT" guy, and in need of help!
I will be in need of about 50 "seats", three will be for receptionist/operators, six will need to be fancy for the executives. I will need to have the ability t connect to my 12 other sites, one of which will have about 90 seats and the others will range from two to twelve. These sites will come later as the old systems are replaced but the upgrade path is central to my decision. I need voicemail, limited auto attendant, DID, and will connect to the carrier via T-1 circuit. I am looking at an Avaya IP-Office and a Nortel BCM solution, Cisco is overpriced so no longer a contender.
I work for the state and this is for a District Attoney's office and needs to be comprehensive yet easy to use. I am also limited (maybe) to state approved vendors.
I know this is a rather broad question but look forward to the discussion and am hoping to avoid common mistakes that I may make based on "uninformed assumptions". Thanks in advance for you time and thoughts.
Bill

Besides being over priced Cisco is 100% IP and you don't need it or want it. I'll let the Avaya & Nortel moderators and techs answer for those systems. What you need is a system that can handle digital as well as VOIP and be able to network. Users that are stationary (receptionist/operators) should have digital phones, because of greater reliability and less expense. For the sites that have a large number of phones use a seperate system networked to your main location. Only use VOIP phones for people that are mobile and for sites that have one or two phones. Can you imagine one of your sites with 90 VOIP phones that do nothing when your network is down or your switch is down? Not to mention the E911 concerns.

I understand that VOIP is here to stay but it has a lot of "growing up" to do.

You should also look at the Samsung product line.

I don't deal with Nortel/Avaya VoIP systems so I cant offer you anything specific there. I can give you a few general things to ask based on my experiences with VoIP and the systems that I have done on Asterisk.

I agree with cmdl_guy on having each site work independently of the whole. Always plan on the internet to burp. This could be a moot point depending on where your incoming lines are. Even if you have your own system at the branch offices, it wont do you much good if you have to dial through the downed internet connection. Might not hurt to look into internet failover or a back-up carrier. Point to Point T1 might be a better solution. Although here in the tampa, florida area the reliability of the copper is determined by how hard it rains. Haven't had any loop issues anywhere for about 6-months tho *knocks on wood*. Although today a Cisco IAD was dropping all channels ranomnly.

I'd suggest having a POTS line brought into each location for use as e911. Chances are it will probably get used for burglar alarm and faxing too. It's an easy method to avoid the liability of e911 compliance. Could also be done through your carrier over VoIP. But again, no VoIP, no e911.

I would look into something like G729 to go between branches as well. There is a significant bandwidth savings versus using G711/etc. G711 uses approx. 80kb/s bandwidth where as G729a uses approx. 24kb/s. So a single T1 link could handle around 3x the channels for every single G711 channel. This is limited to what your vendor supports. The figures are ball-park's as it depends on how the voice is packetized and transmitted. Cisco I believe uses approx. 90kb/s per G711 channel. Your mileage may vary.

If you plan to use SIP endpoints/phones over the internet then you will need to spend some time making sure you have STUN or some other firewall-friendly SIP routing set-up. Problem is also solved by having the server on a public IP but this presents it's own issues (mostly security).

If your mind is not totally set on those systems you may want to find a local ESI reseller in your area. They have a great product line that can handle many of your descriptions.

Toshiba offers a great line of systems that combines both digital and IP. Have done a few and is pretty slick. Toshiba even has an IP phone that can have it's own CO line.

I am beginning to get confused. Maybe I should supply some more info. Regardless of the system I purchase the connection to my carrier Verizon will be a full T-1 all 24 channels with a block(?) of 100 DID numbers. There is no Internet involved at this point. My connection between the two large offices will be 54Mb radio link (they are line of site and only a few blocks away) and a T-1 this is for data. I have a 100Mb connection to Verizon at my office for data and all of my other locations are connected by fractional T-1 and have just been upgraded by Verizon/MCI from a frame type circuit to some alphabet soup name I cannot remember. I will not be using these until I can afford QOS service and the are all full 1.5 T-1 so the remote office is a ways away. I do plan to have separate systems in each location sorry if I did not make that clear and a POTS backup as well for each. I do however want to be able to have all share the main number IE: calling the main switchboard and being able to be transferred to another location. (I could be dreaming here)
The network for voice if I choose an IP solution will be separate from the data side and with the exception of a bridge between the two for unified messaging (future upgrade) will not be connected to each other.
My question is how is the reliabilty affected here. Is there something inherently poor in the qaulity because it is IP or is there concerns that the voice quality ids going to suffer by being IP.
As always, thanks for the input!
Bill

Mitel is another contender, based on your described needs. And Panasonic. The main thing I would suggest is, try to find a vendor that can service the majority of your sites. Or a brand of system that has vendors in each location. This will probably reduce the number of possible brand names quickly! Truly, most name brand systems can support your needs. To take a page from the real estate folks, it's service, service, service. And that means things besides fixing broken phones! Things like name changes on phones, speed dial number changes, and just plain , changes. Now it's time to let the other fine folks here throw in their 2 cents worth. And welcome aboard! John C. (Not Garand)

Most key system manufacturers offer the type of TDM/IP hybrid campus set up you are looking for, and they all do basically the same things for you. One thing to keep in mind is whether or not the system is 'evergreen', that is, will the equipment you buy today still be compatible (or even AVAILABLE) two, three or more years down the road when your other offices come on-line.

Another, and frankly more important point, is the reputation and reliablility of the dealer who sells, installs and services your equipment. Your dealer is every bit as important as the equipment you select, so scrutinize this aspect at least as much as the equipment itself.

Check the installer's link at the top of the page for nearby dealers.

If you compress the voice (going non g711) you of course will lose quality, oh and I would re-check those bandwisth figures as they usually don't include the IP header or sip headers in the equation (please note we use SIP trunking in the office because we have bandwidth to spare). Radio link you need to check for latency..I would suspect if it's fairly close it won't be much of an issue. I wouldn't even consider a SIP phone for this application..MGCP is far superior for VOIP. That being said, what would be the problem with using TDM (traditional digital sets) and networking via VOIP between the locations? Putting of course a smaller system at each location so they could be fully independent regardless of the T1's?

G711 u-law is 64kb/s. SIP/IP/Encapsulation/etc will add around 15 or so kb depending on hardware/software used. You get 80kb for a G711 VoIP packet size (roughly). There is some variance as I mentioned before.

G729 Annex-A is 8kb/s. Again, SIP/IP/Encapsulation/Etc will add about 15kb. You then get 24kb/s. Again the same variances apply.

If you go by Cisco standards, located Here Cisco VoIP Rates , then G711u = 87.2kb/s and G729a = 31.2kb/s. So by cisco you will get ~18 channels over a Data T1 with G711u, or ~50 channels with G729.

Faxing will not work on G729 and DTMF will have to be handled out-of-band for reliable use. When you compress you will have a degradation of audio quality. Whether or not the loss is acceptable is debatable. Typically it lies somewhere between a cellphone's audio-quality and U-Law.

If you have plenty of bandwidth then U-Law is great. Otherwise there are some options that can be considered.

I have seen RS-Air used here in florida for an Office-Office microwave link. It used a tower as a repeater and had a latency of somewhere around 60ms. Was available in speeds up to 15mb up/down. Was used to provide a VoIP link between call centers and worked very well till the hurricanes and tornadoes twisted the dishes on the towers.