Re: Newly revised standards-track RFC

[Roger Fajman <[e-mail]>]

>    The presence of Telnet commands within a TN3270E data message
>    (i.e., between the header and the trailing IAC EOR) is not
>    recommended; neither clients nor servers should send such data.
>    IAC-commands should be sent between TN3270E data messages, with no
>    header and no trailing IAC EOR.  If a TN3270E data message
>    containing an IAC-command sequence (other than IAC IAC) is received,
>    it is implementation dependent how the IAC-command sequence will be
>    processed; the processing may be defered until after the current
>    TN3270E data message has processed.  (Any IAC-command sequence that
>    is received within a TN3270E data message that would normally require
>    response must be responded to at some point to avoid the potential
>    for deadlocks. Any IAC-command that does not require a response
>    may just be ignored.)

It might be easier to implement responding to Telnet commands that
appear in the middle of a 3270 data block as if they occurred before
the block, rather than after.  If the block is being buffered up until
it is complete, then the Telnet commands could be processed while the
block is being received.  I think it should be the receiver's option to
process them as if they occurred before or after.  We probably should
also say that it is OK to deny requests in the middle of a block that
would be accepted between blocks.