This enables or disables receive-side IP header compression, that is, whether the modem expects and decompresses compressed headers on incoming traffic. Unlike the transmit side, this has no perRoute option, so it is a single global switch, meaning the far-end sender's transmit compression setting and this unit's receive setting both need to agree, or decompression will fail for all incoming compressed traffic at once. If the far-end modem has header compression enabled but this object is set to disable, the local unit will not correctly interpret those compressed headers, causing that received traffic to be dropped or misread.