Decide whether the server needs the media
FreeSWITCH can handle media normally, relay it in proxy-media arrangements or negotiate bypass behavior where media avoids the server. These modes have different implications for recording, analysis, transcoding and NAT traversal. Do not enable bypass solely to reduce bandwidth without checking the features that need server-side media access. Draw both legs and the actual RTP destinations. A SIP dialog passing through FreeSWITCH does not prove audio takes the same route.
Verify codec selection per leg
Inspect the accepted SDP and relevant profile or channel codec preferences. If the two legs require conversion, verify that the needed codec modules are present and size the processing workload. A shared codec can avoid some conversion, but application features may still require decoded media. Keep packetization, security and media direction in the comparison. An overly restrictive codec setting can fail a call that would otherwise negotiate successfully. Use a bounded test instead of changing global codec preferences to repair one provider relationship.
Validate the required features
Test two-way audio, hold music, recording, conferencing, DTMF and transfer as applicable. Compare server counters with endpoint evidence and confirm which component terminates SRTP. A protected browser leg and a plain RTP carrier leg have different trust properties. Measure normal and failure behavior under representative load. Document the media mode and its limitations with the call-flow design, especially when a direct path depends on endpoints reaching each other across networks.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.