[Info-vax] SMTP chunk sizes

[JF Mezei]

On 15-03-24 12:44, Jan-Erik Soderholm wrote:

> What did you do when you saw your findings?

Tested the DSL link's speed.  FTP from VMS to ISP-provided FTP server
was considerably slower than FTP the same file from OS-X to the same
ISP-provider FTP server on the same line, using same router.

Once I saw that OS-X was able to do FTP at more or less line speed (once
you remove known overhead such as ATM , PPPoE and IP/IP headers), I knew
that my DSL line was performing correctly and it was just VMS that
somehow didn't perform. I did not investigate further.

Having said that, the VMS host did run TCPIP Services SMTP and did not
have problems sending email out.

If I am not mistaken, FTP has its own flow control mechanism at
application level, whereas once in DATA phase, SMTP just uses the TCP
flow control mechanism.