Configuring CAC limit in Asterisk Free PBX

Would it be possible to restrict the inbound and outbound calls in Asterisk chan_sip channel based on bandwidth usage?

Not directly, no. Asterisk’s channel drivers don’t have a concept of bandwidth utilization. You can use GROUP_COUNT to restrict based on numbers of channels.

What if i got a single channel?
Im able to restrict inbound calls by setting call_limit value. Is there a way I can set CAC limit for outbound calls?

If you have a single channel, then why are we inquiring about limiting anything based on channel? If you’ve a single channel and you’ve a bandwidth restriction, pick the codec that’lll restrict your call to a bandwidth compatible with your connection.

call-limit was a chan_sip option.
chan_sip isn’t something that we deal with.