Should Skype be reliable in a corporate environment?

Whenever we get these problems, we increase the broadband by 5mbps, which makes things better for a few months, and then we get some more staff, and then it starts again.

My theory is that these inevitable peaks, which you generally won't get on a residential connection, are impacting on Skype audio and video, and while the company IT profile is at it is, making something like Skype work consistently is going to be virtually impossible unless we have a dedicated internet connection for Skype.

Is this a valid theory?

That's pretty subjective troubleshooting. You should spend the time to get hard data about your networks (from the edge to the client), especially during times when the audio/video is poor.

You should also look into deciding how you want to use Skype or any IM tool. Most allow you to set your "quality" so that you can decide to not push HD video when it simply isn't necessary. Those kinds of tweaks might help you.

Skype and other solutions like Lync, Jabber, etc. especially when used across your edge connection with your ISP could be subject to degradation since you can't control QoS worth anything. Internal IM/video collaboration is better, but still can have minor issues even across large bandwidth connections.

Should Skype be reliable in a corporate environment?

In the end, your company has to decide what solution works well for it. Skype itself isn't the issue here, no more than any IM client would be.

I've done quite a bit of research on this over the last month or so.

My conclusion is that unless you use the Skype Tools for Active Directory, or are in a position to use a Proxy server for all your Internet traffic, Skype is not a good corporate solution.

This is because Skype performance cannot be guaranteed in environments using Port Address Translation

http://www.nightbluefruit.com/blog/2014/05/is-skype-an-appropriate-tool-in-corporate-environments/

Quote from Skype Administrators Guide:

2.2.4 Relays

If a Skype client can’t communicate directly with another client, it will find the appropriate relays for the connection and call traffic. The nodes will then try connecting directly to the relays. They distribute media and signalling information between multiple relays for fault tolerance purposes. The relay nodes forward traffic between the ordinary nodes. Skype communication (IM, voice, video, file transfer) maintains its encryption end-to-end between the two nodes, even with relay nodes inserted.

As with supernodes, most business users are rarely relays, as relays must be reachable directly from the internet. Skype software minimizes disruption to the relay node’s performance by limiting the amount of bandwidth transferred per relay session.

ie regardless of what bandwidth you have, when using PAT, you will still be dependent on resources over which you have no control.