This week, we have a semi-rehash of earlier tips (#51 and #67), based on some investigation work that’s been done inside Microsoft’s own IT group.
If you’re going to join a Lync call (especially if you’re using video or app sharing, using a Roundtable/Polycom CX5000 device etc), then best practice is to use a wired network connection. If you’ve a laptop which is on WiFi, then you need think about your connection if you want the call quality to be at its best.
Networking preference
Windows 7 and Windows 8 prefer wireless networks, on the basis that if you’re connected to a WiFi network, then there’s a reasonable chance you’re on a laptop and therefore you’re likely to move around.
Lync really wants a nice, fast, low-latency network connection. In a typical Microsoft office environment, most users have laptops and most will be connected to wireless, meaning the WiFi is going to be pretty 
congested, compared to a wired network at least. And congested, slow(er) networks don’t make for great call quality (as is sometimes evidenced by the network connectivity icon).
The Lync client is network-aware, though, and will default to using the highest-performing network it can. So, if you’ve a laptop that’s on WiFi and plugged into Ethernet, then Lync will use the wired network in preference. There’s one important consideration though – Lync can’t switch an in-progress call between WiFi and wired!
So if you establish a call on Wireless, then see the dreaded red bars that tell you all is not well with your network, simply plugging in a network cable won’t do you any good. You’d have to drop the call and re-establish it to make 
a difference.
To be sure which network you’re using for the call, fire up Task Manager – right-click on the Taskbar and choose Task Manager, or just press CTRL-SHIFT-ESC.
In Windows 7, select the Networking tab, and if you’re using Windows 8 Consumer Preview, look under Performance and you’ll see little graphs of how your networks are doing. This will help you see which network is being used to carry all that data.
A simple way of checking the behaviour is to use the Lync client’s test call facility and see which one spikes…
If the WiFi is taking the brunt, then make sure the wired network is connected OK, then disconnect the call and re-establish it, and you should see the wired network usage jump up.
No real need to disable WiFi, but if you have a switch on your laptop to do that, and you’re a suspicious sort (or untrusting type), then doing so may hurry the process along.
