This read-write Integer32 (0-2147483647) configures, in bytes, the size of the fax information field used during T.38 fax relay sessions on the gateway. An admin tunes this value to balance packetization overhead against how much fax image data is carried per IFP packet, which affects fax reliability over the IP network. For example, increasing t38FaxInfoFieldSize on a low-loss network can reduce packet overhead per page, while lowering it on a lossy link limits how much fax data is lost if a single packet is dropped.