I understand that the h323-voice-quality VSA conveys the calculated ICPIF factor, which is supposed to be a positive integer. However, on many occasions, this VSA contains the value "-1" or "h323-voice-quality=-1"(In fact, it appears in some examples of this very web site). What is the meaning in this case? Clearly, it can't be used but there must be some reasoning behind it that I'd like to know. Same goes for the value "0", which is unrealistic when codecs other than G.711 are being used, and for any ICPIF value over 50.
The value should be in from 0 - 34 not -1.This should be calculated from the icpif for the call. Two caveats with
this value. First is that it relies on rtcp (which for example our ip phones do not support). The second is that the call needs to be longer than 10 second in duration. If neither of these conditions are true, you should expect it not to be set; or as shown as -1.
As a workaround try upgradig the IOS to the latest one.