SCN VPN QoS Question 1

[kswinnen]

Hi guys,

A question, I need to setup scn on 3 sites. All of them have IP500 pro.

I want to have a good quality connection towards all the sites.

What's the best way to do it?

Setting up Site-to-Site vpn with Qos, is this going to be enough? What's the minimal bandwidth you need? Do I need to check more influences?

Thanks!

 

[B657]

Hi Kswinnen,

The most important factor here is going to be the quality of the links between the sites.

A business class adsl is going to be contended at 20:1 and will only offer 256k upstream (voice over the scn requires bandwidth in both directions). A call across the SCN will require abouth 30k but as soon as the call goes on to the open internet you can not guarantee any QoS even if you have configured it on your routers, so the call is subject to jitter and latency.

Voice will work over VPN some of the time but there will be occasions where it is of very poor quality, and as soon as the users lose some faith its really hard to get them back on side.

You really need to be looking at MPLS or leased line or possibly SDSL to stand a chance, but clearly there are cost Vs ROI implications here.

That said, as soon as the data links are established the config on the IPO side is pretty straight forward. I think there are tech docs to assist, and i can post a link if you want me to.

You will also need the advanced and voice networking license.

 

[kswinnen]

Hi B657,

Thanks for the quick response to my question!!

Now it's pretty clear to me!

So ADSL is no go!?

Kristof

 

[B657]

Speaking from experience, we have never managed to get it working to a standard that meets the customer requirement and expectation; even if we set the expectation that the quality of the voice is only as good as the quality of the data link.

Personally i would not touch ADSL for this kind of application, but maybe someone out there disagrees.

 

[Albus]

It is possible to have SCN with ADSL lines, but the voice is kept on ISDN using short codes. This gives the benefit of SCN regarding status, dialing, name presentation ect. But there is still superiour voice quality, since it is transported by public ISDN.

The problem here is, if you have a central VM pro. This is only working as voip call. If anyone has a solution to have voicemail on the PSTN instead of the IP-Line, you are highly welcome!

 

[intrigrant]

@Albus, create a dial-up intranet service between the SCN sites and establish a PPP connection over ISDN.
This enables you to have a VoIP connection over the ISDN and VM Pro connections will work.
Nevertheless, Voip over ADSL can be ok but the upload band limit and overbooking are parameters to be taken care of.
I would not use a "home" adsl for Voip, get yourself a commercial DSL line with enough bandwith, no overbooking and no datalimit.


NIHIL NOVI SUB SOLE

 

[Bas1234]

kswinnen...

Maybe this link will help you...

http://members.optusnet.com.au/hagoo/iporesource/applications/VoIP BW Calculator v2.xls

greetzzz....Bas

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It works! Now if only I could remember what I did...
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[Albus]

@intrigrant, Isn't that connection up all the times as soon as it is triggered for the first time? SCN has periodic traffic, so this connection is not only up when voicemail is needed, but more or less permanent.
At least until 4.0 a shortcode for internal numbers at remote SCN sites was not used as soon as at least one channel in the IP-Line for SCN was enabled. This means, that the first call was routed over the VoIP line wich was not desired.