Queries on JVB

Hi Experts,

I wanted to understand, if JVB honors the “b=AS:” attribute? If SDP is munged in such a way that the answer from an endpoint going out to JVB has the “b=AS:” attribute set, would JVB honor the indicated bit-rate? If not, are there any other ways to achieve this outcome?

Also, as a related-question, what exactly is the significance of the “x-google-start-bitrate” attribute?

Thanks.