[e2e] keep-alive probe instead of persist probe

[Prakash Khemani]

Can I get away with generating a keep-alive-probe-look-alike in persist
mode rather than the usual persist probe? Will it work with the other
TCP stacks out there?

The persist probe retransmits a old byte of data or generates a new byte
of data.

On the other hand the keep-alive probe is much more light weigth. It is
a pure-ack packet with sequence number equal to (send_unack - 1). If
every stack is going to ACK a keep-alive probe with the current window
value - then it can also double as a persist probe.

Anyway - why do the standards prescribe that the persist probe should
carry data?

Thanks,
Prakash