I have already set the MTU to 3000 on the PC side. On the STM32H743 side, I have set the RXBUFFLEN, MTU, PBUF_POOL_SIZE, and other related memory configurations to 3000. I have configured and enabled Jumbo Frame and disable Jabber disable and Watchdog disable with ETH->MACCR |= (ETH_MACCR_JE | ETH_MACCR_WD | ETH_MACCR_JD | ETH_MACCR_GPSLCE);However, when I ping the STM32 from the PC with 1472 bytes, it is successful, but pings larger than 1472 bytes fail. Why is this happening? What have I not configured correctly?

Visitor II

Question

How to enable jumbo frames on STM32H743IIT6？

I have already set the MTU to 3000 on the PC side.
On the STM32H743 side, I have set the RXBUFFLEN, MTU, PBUF_POOL_SIZE, and other related memory configurations to 3000.
I have configured and enabled Jumbo Frame and disable Jabber disable and Watchdog disable with ETH->MACCR |= (ETH_MACCR_JE | ETH_MACCR_WD | ETH_MACCR_JD | ETH_MACCR_GPSLCE);
However, when I ping the STM32 from the PC with 1472 bytes, it is successful, but pings larger than 1472 bytes fail. Why is this happening? What have I not configured correctly?

Technical Moderator

Hello @TTL, and welcome to ST Community!

Have you configured the maximum frame length (Giant Packet Size Limit, GPSL) in the ETH_MACECR register?

It must be greater than your intended frame size (payload + IP + TCP/UDP + Ethernet header + FCS).

Best regards,

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