If you ever deployed any SIP trunk in a multi-vendor enterprise environment, the very first thing you need to decide, what kind of codec I want to use on the SIP trunk. Normally in traditional IP telephony networks the well-known practice is to use compressed codecs like G.729 over the wide area network.  Sometimes Service Providers are strict in the codec choice, you might need to select one of the codecs offered from them. If you select G.729 because this is what your current IP telephony environment supports then later on you might have problem when you would like to connect your Lync/SfB e...