Technical > Photos of Broadband gear > Analog Voice Gateways

reply to BiggA

Re: Analog Voice Gateways

reply to tubbynet

reply to BiggA
Yes.

reply to cramer
On the new build outs I always tell my customers to drop to cables per user. Even if they don't terminate the second at least get the cable there for future use.

In a retro deployment 99.999% of the time the customer isn't going to pay for the second drop unless it's absolutely needed. To be honest I don't blame them.

reply to BiggA
I've got an upcoming deployment were I am going to use 5 IAD-2431-24FXS and a dozen IP phones. Even though I have the owner running 2 Cat5e to each room there is absolutely no need for IP phones in each room.

There are some situations where IP phones are not just needed. I suspect that he also has a similar situation.

reply to jmich
Everyone sees different things, all the VoIP setups I've seen have segmented the phones from the data, when it comes to having the availability to do so. Obviously some cases there's existing cable and that's not possible.

reply to jmich
Why burn twice as many switch ports when you dont have to?

Switch ports may be cheaper than router ports, but they still have a cost, and youre only trying to save yourself from a situation that *might* be a problem which if it does occur can be rectified easily enough.

:-P

Good point. You may as well use the phone hardware you're paying for.

reply to jmich
I see no reason to separate voice from data in a lot of instances: It simply doubles the risk of network failure: In most cube settings how can someone do a job with a phone if the network is down? I certainly couldn't... (Give me a network only and I am 80% productive. Give me a phone only and I am 0% productive)....
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reply to BiggA

Or you could just keep them on the same network... Just like home users using VOIP do.

reply to BiggA
Tell it to the Vonage crowd. Despite the thing being upstream of their router where it can "apply QoS", people still have call quality issues if the line is moderately used. VoIP within a company LAN, you'd think that wouldn't be a problem, but it can, and does, happen.

In the end, there are as any reasons to keep voice and data as isolated from each other as possible, as there are not to. The best way to learn is having them sneak up and bite you on the a**.

(I see it myself with VoIP over IPSec. Back when TWC was 384k up, you best not do anything while using the phone. Now at 1M up, you just have to be careful not to push it while on the phone. Unless you like a stuttering phone.)

On a 100mbit line, it's unlikely to happen. I don't seem to have issues with my AT&T Microcell when I'm hitting the 'net hard, probably because I have the Microcell god-esque QoS priority in the router.

I do have general upload jamming issues though, so I've cut my torrents, backup, and Google Music down to 1mbps each, but if two or three of them kick on at the same time, or with Dropbox, then everything kind of grinds to a halt on the web browsing side of things.

It's not a question of bandwidth to the internet for many of these campuses, it has to do with QoS and congestion on the internal network. Additionally, the number of lines many of these enterprises have would take a heavy toll in bandwidth (they number in the hundreds, if not thousands). Remember that the average VoIP call takes about 130kbps of bandwidth (counting overhead), or about 80 lines with 10mbps of bandwidth.

I'll give my two cents having designed a network for a higher education campus.

Due to security issues, and the existence of an original PBX, only some lines were replaced with VoIP, notably offices and labs. Classrooms and Emergency phones remained on the PBX due to technology limitations and cost. Each of the VoIP phones needed a new line to be run for every phone since the existing wiring was based off of Cat 3. The network was designed so that voice traffic was independent of the data network to help with latency, security, and network congestion issues. Likewise, the IP cameras on campus are also on an entirely separate network for security reasons. This particular organization uses PoE for the switches at quite an expense, and runs an Avanya PBX system for VoIP, and a Siemens PBX for POTS.

The POTS infrastructure was not transitioned using FXS devices for the simple reason that the existing PBX was in place, and for emergency situations should the core routers fail, the campus would still be able to reach out through conventional means.

The problem with VoIP is that it requires you to have a stable, consistent, and good quality internet connection with little loss. Should your internet connection fail at any time, then you have serious issues about not being able to contact the outside world. "Use your cell phones" is not an acceptable answer to these enterprises.

Why are the bitrates cranked up so high? Cell phones are something like 10kbps.

"Use your cell phones" should be an OK answer, as they will always work. Of course, you could always have a backup internet connection in case one fails...

Standard VoIP bitrates (like G.711) are at least 40kbps, and many are 50 or 64 plus packet overhead. These are land lines that have to be clear to the other end. There's a reason Verizon ran those "can you hear me now?" ads, since 10kbps is terrible quality considering AM radio is 24kbps.

It will never be acceptable to Fortune 1000 companies, especially when people/clients go to call them. Additionally, if you add that much cell traffic, the towers can be overloaded, not to mention the cost of minutes. It just has to work, because that's what you are paid to do. Yes, you always have a backup but even backups fail.

Regular phone systems can bite the dust too, it's not like any of this stuff is super reliable. At least VOIP you could have multiple bandwidth providers as redundancy, as opposed to one phone company where if something blows up.

It's hard to find hard data, but AFAIK, the highest bitrate WCDMA can handle is 23kbps, and WCDMA on the iPhone is higher than landline quality. Admittedly, there's probably a lot of processing going on in the iPhone, but it is able to pull it off.

Not sure if I've ever used a VOIP system, but a good cell phone connection (like AT&T 3G on the iPhone 4S) definitely sounds better than a copper landline. Again, might be processing and massaging, since Apple spends a LOT of time and money on every detail of the thing.

POTS is still more reliable than cell phone service that's for sure. The problem with redundancy I already stated before. I've also previously stated the reason companies keep POTS, mostly due to security and cost.

Higher than land line quality perhaps, but not better than VoIP. Additionally quality is not important in classrooms and for emergencies.

That's subjective and depends on the quality of the line, the distance, the age of the line, the phone handset, and variety of other factors.