How many packets are in a single FEC block?

This option describes a 1+1 FEC scheme, which is not the default or common FEC block structure in Cisco SD-WAN.

This option describes a 1+4 FEC scheme, which would generate too many parity packets for typical SD-WAN deployments and is not the standard.

This option describes a 2+1 FEC scheme, which is not the default or common FEC block structure in Cisco SD-WAN.

In Cisco SD-WAN, Forward Error Correction (FEC) typically uses a 4+1 scheme, meaning that for every four data packets, one parity packet is generated. This parity packet allows the receiver to reconstruct one lost data packet within that block, improving application quality over lossy links without requiring retransmissions.

While some parameters of FEC might be tunable or chosen, the question asks about how many packets *are* in a single FEC block, implying the standard or common configuration, which is 4 data packets and 1 parity packet in Cisco SD-WAN.