Owens-Christopher@cs.yale.edu (Christopher Owens) (07/27/89)
A more general question that someone may be able to explain to me. Is it true that doing binary file transfer using MNP error-correcting connections implies the need for hardware (RTS/CTS) flow control? My reasoning: MNP link needs some kind of flow control, since the modem-to-modem link can be arbitrarily slower than the computer-to-modem link. But, if doing binary file transfers, XON and XOFF may appear in the data stream, so XON/XOFF flow control is no good. Therefore, one needs hardware flow control. Is this right? Is there any way around this? thanks, ARPA: Owens-Christopher@cs.yale.edu UUCP: {harvard,cmcl2,decvax}!yale!Owens-Christopher BITNET: Owens@yalecs
njs@scifi.UUCP (Nicholas J. Simicich) (07/27/89)
Yes, this is generally true. The line can be extremely slow, so sending data to the modem can overrun it. I frequently do binary data transfer over a modem that uses error correction, and which does not have flow control (because my computer does not support it). To make this work, you need to use a protocol which requires end-to-end acknowledgements, and your modem must be able to buffer. The maximum amount of unacknowledged data under the protocol must be less than the buffering capacity of the modem. -- Nick Simicich --- uunet!bywater!scifi!njs --- njs@ibm.com (Internet)