 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| n |
At
any time, TCP sender sets retransmission timer for only
|
|
one
packet
|
|
|
| n |
If
acknowledgement for the timed packet is not received
|
|
|
before
timer goes off, the packet is assumed to be lost
|
|
|
| n |
RTO
dynamically calculated
|
|
|
|
– |
Connection
may be between two machines on same LAN (want
|
|
|
low
RTO value) or two machines on opposite sides of Atlantic
|
|
|
(need
higher RTO value)
|
|
|
|
– |
Network
connection between two machines introduces predictable
|
|
|
and
constant delay per packet (can use tighter bound) or highly
|
|
|
variable
packet delay (use less tight bound to avoid unnecessary
|
|
|
retransmissions)
|
|
|
|
– |
Use
observed time difference between packet sent and
|
|
|
acknowledgment
received to estimate RTO
|
|
