Robust Header Compression - Robustness

Robustness

The size of the sequence number (SN) field governs the number of packets that ROHC can lose before the compressor must be reset to continue. The W-LSB algorithm is used to compress the SN in a robust way. The size of the sequence number in 1 and 2 byte ROHC packets is either 4 bits ( −1/+14 frame offset ), or 6 bits ( −1/+62 frame offset ), respectively, so ROHC can tolerate at most 62 lost frames with a 1-2 byte header.