Logic-layer failures in the ST 2110 domain.
Verify the IGMP Querier. If the switch isn't issuing queries, the IGMP Join from the receiver will time out, and the gateway will never see the request to start the flow.
Check the SFP TX-Power and Admin State . If either is incorrect or disabled, the interface will not pass multicast traffic.
A classic SDP Mismatch . . The receiver is getting packets but cannot interpret the "Map." Check for discrepancies in 1080i vs 1080p or mismatched frame rates in the SDP file.
Usually points to Packet Pacing or PTP Sync errors. If the stream is "Wide" and the receiver expects "Narrow," buffer overflow can cause momentary black frames or flashing.
If your receiver only supports 8-bit but the flow is 10-bit, you'll see purple/green artifacts. Ensure the gateway is set to truncate or the SDP matches hardware capability.
The SFP transceiver's TX-Power (Transmit Power) must be within the acceptable range for the link to work. If the TX-Power is too low or shows "No Signal", the SFP is not transmitting light properly.
Additionally, the port's Admin State must be set to Enabled. If the Admin State is "Disabled" or "Shutdown", no traffic (including multicast) will pass, even if everything else looks correct.
A classic SDP Mismatch
This error means the receiver is successfully receiving RTP packets, but it cannot decode or display the video (or audio) because the incoming stream parameters do not match what the receiver expects according to the Session Description Protocol (SDP).
1. Compare the active SDP being used by the receiver with the actual stream parameters.
2. Use a tool like Wireshark + SDP dissector or a dedicated 2110 analyzer to see what the sender is really transmitting.
3. Check NMOS IS-05 connection management — ensure the correct SDP is being pushed to the receiver.
4. Verify both sender and receiver support the same formats and that the gateway/media gateway is not altering parameters unexpectedly.
SDP mismatches are one of the most frequent issues in ST 2110 deployments. Always treat the SDP as the “contract” between sender and receiver — if they don’t agree, the stream will fail even if packets are arriving.