[e2e] What happen "after slow start"

cys yschoi at gmail.com
Mon Sep 26 00:32:07 PDT 2005

For high-speed networks, setting initial ssthresh high can be desirable.

Suppose, TCP connection just started

the saturation  point(or steady state): cwnd=100
ssthresh : a large value.

During slow start, if current cwnd=99, TCP doesn't experience packet loss.

but next rtt, cwnd =198 and 98 packets will be dropped.

as far as i know, RTO and 3Dup. Ack are the only ways to detect packet loss.

if we use Reno, multiple packet losses from a window of data will
results in rtx timer expire.

Thus, TCP enters slow start again.

But many documents and TCP tutorials only shows following case.

"Slow start-> pkt loss -> Fast retransmit&Recovery-> congestion avoidance "

"Slow start-> pkt loss -> rtx timer expire-> slow start"

I think the latter case will happen more frequenlty than the former case.

Are there any special treatment for packet loss during slow start?


More information about the end2end-interest mailing list