Ain't It a Bear? (Q16)

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There has been recurring confusion over bearer capabilities and in particular the Information-transfer-capability, Transfer-mode, and Information-transfer-rate fields. Here is some pseudocode to show what to set these fields to. I agree that their utility is somewhat questionable, but at least this will show you some sensible values to use. I left multirate out of this logic to make it easier to understand, but a very robust implementation might want to allow the user or administrator to specify this.

Pseudocode

if audio-only then
    Transfer capability = "Speech"
    Transfer rate = "64 kbit/s"
else (audio-and-video)
    if restricted (to 56kbps ISDN) then
        Transfer capability = "Restricted digital information"
    else (unrestricted, e.g., 64kbps ISDN)
        Transfer capability = "Unrestricted digital information"
    endif
    if second called party number (and placed in SETUP.destExtraCallInfo)
then
        Transfer rate = "2 x 64 kbit/s"
    else
        Transfer rate = "384 kbit/s" (or, I suppose, "1536 kbit/s" or "1920 kbit/s")
    endif
endif

Transfer mode = "Circuit mode" (NEVER "Packet mode"!)