Espressif ESP32-S2 Programming Manual page 1185

Chapter 2. API Reference
CONFIG_LWIP_UDP_RECVMBOX_SIZE
Default UDP receive mail box size
Found in: Component config
Set UDP receive mail box size. The recommended value is 6.
UDP receive mail box is a per socket mail box, when the application receives packets from UDP
socket, LWIP core firstly posts the packets to UDP receive mail box and the application then fetches
the packets from mail box. It means LWIP can caches maximum UDP_RECCVMBOX_SIZE pack-
ets for each UDP socket, so the maximum possible cached UDP packets for all UDP sockets is
UDP_RECCVMBOX_SIZE multiples the maximum UDP socket number. In other words, the big-
ger UDP_RECVMBOX_SIZE means more memory. On the other hand, if the receiv mail box is too
small, the mail box may be full. If the mail box is full, the LWIP drops the packets. So generally we
need to make sure the UDP receive mail box is big enough to avoid packet drop between LWIP core
and application.
Range:
• from 6 to 64
Default value:
• 6
Checksums Contains:
• CONFIG_LWIP_CHECKSUM_CHECK_ICMP
• CONFIG_LWIP_CHECKSUM_CHECK_IP
• CONFIG_LWIP_CHECKSUM_CHECK_UDP
CONFIG_LWIP_CHECKSUM_CHECK_IP
Enable LWIP IP checksums
Found in: Component config
Enable checksum checking for received IP messages
Default value:
• No (disabled)
CONFIG_LWIP_CHECKSUM_CHECK_UDP
Enable LWIP UDP checksums
Found in: Component config
Enable checksum checking for received UDP messages
Default value:
• No (disabled)
CONFIG_LWIP_CHECKSUM_CHECK_ICMP
Enable LWIP ICMP checksums
Found in: Component config
Enable checksum checking for received ICMP messages
Default value:
• Yes (enabled)
Espressif Systems
> LWIP > UDP
> LWIP > Checksums
> LWIP > Checksums
> LWIP > Checksums
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