Codec Negotiations in Your CCIE Collaboration Preparation
Codec negotiation is a topic that gets glossed over without much consideration in the studies of most students. There’s really not much to it, right? All we have to do is slap a couple of Regions on two different system endpoints and…voila, we have successfully negotiated a codec! Can it be that simple? Like most answers to rhetorical questions in the tech world, “It depends.” A simplistic approach like the one just described above is a great place to start, but it doesn’t take into account key call flow elements such as early/delayed offer, Audio Codec Preference Lists, or call routing across CUBE, CUCM or CUCME. What if the codec should be different based on the originator of the call? These are all examples of key issues involving codec negotiation that we must wrap our mind around if we are to be successful in our CCIE Collaboration endeavors.
Let’s examine the requirement of routing a call between a 9971 Phone registered to the HQ CUCM cluster (HQ Phone 1) and a 7965 Phone registered to the SB CUCM cluster (SB Phone 1). In this example, consider that a SIP Trunk is configured directly between clusters in order to route Continue reading