VoIP and WAN Bandwidth

64kbit/s does seem like a fairly sensible ammount, i'll do some digging regarding the number of outgoing calls.

Just looking to hear peoples experience with this really.

Surely you would want QoS configured though because what if someones downloading a file at 200kb/s leaving you with too little bandwidth and poor VoIP
 
Is that 64kbit/s both up and down, or 32k up, and 32k down?

Have you limited the outgoing calls so any more over a certain amount can not be made and they must wait for an available 'line'?

I guess not though since you've not had any problems...
 
That's saying upwards of 90kbit/s, not 64? Or were you refering to the quality when you said 64kbit?

I've got a pretty limited understandinf of VoIP, at what point does a VoIP to normal landline call switch to the PSTN network and stop using your WAN link, or does it never reach the WAN link and is converted to PSTN before it leaves your network?

If that makes any sense at all ha-ha
 
By not using your WAN link for calls outside of your LAN, aren't you missing out on the majority of potential cost savings?

If you had say remote branch offices, you could perhaps use VoIP out to them over a WAN link, but all totally external calls over PTSN?
 
Yeah :)

Well, if remote branches will work then there's no difference between using the WAN for the rest of calls made to entirely external destinations.

If you have a leased line to the ISP, then they handle the switching to the PSTN network from there on, surely it would effectively be the same as calling a remote branch over VPN?
 
Right, I just need to get a little bit more of an understanding around hosting it yourself.

So effectively, you get some hardware in that allows you to convert a VoIP call from IP to PSTN?

Doesn't this mean you are no longer using an internet link for the call though?

Bare with my guys I really don't know too much about this, and most information I find seems to be around home-consumer type VoIP.

Thanks for the help so far :)
 
So you effectively use one 64kbit ISDN line, or a paired 128kbit line for one voice conversation, depending on the codec you select?

I'm guessing in theory then, renting an ISDN line and using that for VoIP should be cheaper than paying for a typical phone call? Or have I misunderstood?
 
Ah I see. I was just thinking to a codec that was posted earlier that had an ethernet requirement of 93kbit/s.

I suppose this all gets a little more complicated it you wanted to secure communications over the ISDN link, is that even possible?

Am I right in thinking that by using the ISDN line for outgoing calls rather than paying BT or whatever, you're monthly telecomms bill could possibly be reduced.
 
bigredshark, i'm going to drop you an e-mail this evening :)

I'm still not too sure I understand all this renting ISDN lines for outgoing calls, can is it really be cheaper than just having an ISP doing this for you?

I like to understand the technology and i'm not too sure what's going on here... Someone do a topology in paint ha-ha
 
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So ISDN is a safe bet and generally more reliable? Is it often cheaper though? I'm assuming you can only use 1 ISDN line per call? So even if you're using a codec that requires 32kbit/s, you'll have to use one 64kbit ISDN line?

I need to do some reading as i'm not entirely sure how someone from the outside calls a VoIP phone. I'm guessing the basics of it are they dial your number, and the CallManager then routes it to the associated IP phone, in a similar fasion to NAT?
 
When you make a call using an ISDN line it establishes a direct circuit to the landline then? Rather than a typical IP connection with your ISP?

So talking about the bottom line... exactly where do these 'cost savings' come from when people talk about VoIP. I guess if the majoriy of your external calls are long range, then renting ISDN lines could effectively be cheaper than paying your usual telecomms bill? Or am I barking up the wrong tree?

I understand it's easier to manage (although probably more difficult to troubleshoot) than a PBX network.
 
I was under the impression that unless you switch it to PSTN or ISDN yourself locally then you'll have to pay to have your service provider do so?

I'm thinking specifically about calls that are made to external landline numbers, not VoIP phones.

I really need to get a better understanding on this ha-ha :D
 
I'm not followijng you.. with the exactly comment lol.

I'm trying to workout if it is supposed to be more cost effective having an ISDN line rather than a typical phone line, which doesn't really seem likely. Although you'll be saving money on any calls to branch offices as they will be VoIP to VoIP calls and will take place entirely over a WAN VPN link.
 
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